Advanced Data Classification Framework for Enhancing Cyber Security in Autonomous Vehicles

Abstract

Autonomous vehicles (AVs) have revolutionized the automotive industry by leveraging data to perceive and interact with their environment effectively. Data safety is essential for supporting AV decision-making and ensuring reliability in complex environments. AVs continuously collect data from multiple sources like LiDAR, RADAR, cameras, and ultrasonic sensors to monitor road conditions, traffic signals, and pedestrian movements. An effective data classification framework is crucial for managing vast amounts of information and securing AV systems against cyber threats. This paper proposes a comprehensive framework for AV data classification, categorizing data by sensitivity, usage, and source. By integrating a review of the literature, real-world cases, and practical insights, this study introduces a novel data classification model and explores sensitivity criteria. The findings aim to assist industry stakeholders in creating secure, efficient, and sustainable AV ecosystems.

1. Introduction

Data, whether in the form of numbers, words, or images, represent a critical asset in any organizational context. Safeguarding the privacy and security of data is imperative, as attributes like accuracy, validity, relevance, completeness, accessibility, and consistency are vital for maintaining data integrity and usability [1]. Data classification, which involves categorizing data based on sensitivity levels throughout the data lifecycle, is central to determining appropriate security measures and evaluating the value of data as a business asset. Factors such as risk, disclosure, creation method, personal user data, and usage patterns guide this classification process [1].

In recent years, the integration of advanced technologies into the automotive industry has ushered in a new era of transportation, marked by the rise of autonomous vehicles (AVs). Data lie at the core of AV functionality, enabling these systems to perceive, interpret, and interact with their environments. Systematic data classification in the context of AVs organizes, categorizes, and labels diverse data types, forming the foundation for intelligent decision-making capabilities. Proper classification ensures AVs can navigate complex environments autonomously, securely, and efficiently, while addressing potential cyber threats that may compromise safety and reliability.

The rapid global adoption of AVs highlights the need for robust security measures to tackle emerging cyber security challenges. Studies predict a compound annual growth rate (CAGR) of 19.56% in the U.S. AV market between 2023 and 2030, driven by technological advancements and consumer demand for innovative transportation solutions [2].

Given this backdrop, establishing a comprehensive framework for data classification in AV networks is a crucial step toward enhancing cybersecurity resilience. Proper classification of the diverse data transmitted and processed within AV environments serves as the first line of defense against such risks. This research aims to address these challenges by undertaking the following:

i.

Identifying diverse data types and sources within the AV environment to gain a comprehensive understanding of their role in AV operations.

ii.

Developing a framework for classifying these data types based on criteria such as sensitivity, relevance, criticality, and their potential impact on AV operations.

Through a thorough review of the existing literature and real-world cases, this study contributes to advancing autonomous driving technology while providing a foundation for cybersecurity professionals to develop robust defense measures to protect AV systems. By classifying multiple data types into well-defined sections, security personnel can focus their efforts on securing specific classified sections collectively, rather than devising individual security measures for each type of data. This approach streamlines the implementation of robust defenses, ensuring more efficient and effective protection of AV systems against evolving cyber threats.

This paper is structured to provide a comprehensive understanding of data classification in autonomous vehicles. A review of related works and the literature is first conducted in Section 2 to highlight existing research and identify gaps in data classification and cybersecurity within AV environments. The vulnerability landscape of AV systems is then analyzed in Section 3 by referencing real-world cyber-attack scenarios, emphasizing the critical need for enhanced data security. In Section 4, data types and sources in traditional vehicles are examined as a foundation, followed by an exploration of the data and sources unique to AV environments, including their functionalities and roles. Data flows within AVs are then analyzed in Section 5 to illustrate the essential role of data in enabling autonomous operations. In Section 6, we provide an overview of autonomous vehicle data flow. The proposed data classification framework for autonomous vehicles is described in Section 7, with data categorized based on sensitivity, usage, and sources to enhance security and operational efficiency. Finally, we provide the conclusions in Section 8.

2. Related Works

While a comprehensive data classification framework explicitly based on usage, sensor type, or sensitivity in autonomous vehicles (AVs) has yet to be fully established, significant strides have been made in related domains, offering valuable insights and foundational approaches.

Several pivotal studies have laid the groundwork for comprehending and subsequently refining the methods of data classification in AVs. In [3], the evolution of assistance systems into the current state of autonomous vehicles is explored. This study introduces a classification approach based on the degree of data sensitivity and presents a software design to assist manufacturers and administrators in addressing data protection challenges effectively.

The role of deep learning algorithms in data classification has also been extensively studied. For instance, Ref. [4] highlights the effectiveness of the YOLOV3 algorithm in improving image classification for AVs. The study emphasizes the importance of advanced deep learning techniques for accurate environmental image classification, which is essential for safe and efficient navigation. It also identifies challenges, such as the need for high computational power and optimized algorithms.

Further, research on machine learning for object classification has introduced methods for categorizing objects in AVs. In [5], a novel approach organizes datasets based on movement characteristics, enhancing accuracy in identifying vehicles and other objects. Similarly, Ref. [6] proposes a collaborative method for connected self-driving cars, using encryption and secure data-sharing techniques to preserve privacy while enabling seamless sensor data exchange for safe object recognition.

The management of personal data in AVs has also been a focal point of research. In [7], the authors emphasize the importance of protecting personal information in compliance with laws such as GDPR. This study outlines strategies for sorting and managing data while safeguarding individuals’ privacy, highlighting the critical balance between functionality and ethical data usage.

These studies collectively address various aspects of data classification and management, including algorithmic advancements, collaborative frameworks, and privacy considerations. Building on this foundational work, our research aims to address the gaps in establishing a comprehensive data classification framework for autonomous vehicles (AVs). While previous studies have provided significant insights into specific elements of data security, we adopted a holistic approach by leveraging an extensive array of academic papers and literary resources.

Data classification in autonomous vehicles (AVs) is an evolving field, focusing on data protection, object classification, and privacy preservation. Studies in the past have highlighted the use of advanced machine and deep learning techniques to enhance AV functionality and safeguard user privacy. Yet, a specific focus on the precise classification of data types within AV network environments, considering factors such as data sensitivity, remains uncharted territory. While the current body of research provides valuable insights into managing and utilizing data in AVs, it stops short of detailing a methodology for categorizing data based on sensitivity or other critical parameters. This research gap highlights the need for a comprehensive data classification framework that integrates data sensitivity, usage, and sensor-specific vulnerabilities.

Previous studies have offered a detailed understanding of various autonomous vehicle sensor functionalities and their use cases within autonomous vehicle environments. These studies provided a foundation for identifying the types of data generated by various sensors, including cameras, LiDAR, and radar systems [8,9,10,11]. Additionally, studies [12,13,14] contributed to a comprehensive understanding of the vehicular network ecosystem, encompassing Vehicle-to-Vehicle (V2V), Vehicle-to-Network (V2N), Vehicle-to-Infrastructure (V2I), and Vehicle-to-Everything (V2X) communications. This knowledge is instrumental in systematically mapping data sources, a crucial step in developing a data classification framework.

To identify vulnerabilities and attack surfaces, we turned to research that explored real-world scenarios and threats. For instance, researchers highlighted specific attacks on forward-looking cameras, such as laser blinding and spoofing, which underscored the critical need to secure visual data against such disruptions [15,16]. Similarly, El Zorkany et al. in [13] revealed vulnerabilities in Dedicated Short-Range Communications (DSRCs) and IEEE 802.11p protocols, which could be exploited to disrupt traffic management systems. This study emphasized the importance of implementing authenticated and encrypted connections to protect against cyber attacks. Furthermore, the previous study examined Vehicle-to-Infrastructure (V2I) communications, identifying risks like Man-in-the-Middle (MitM) attacks, replay attacks, tampering, and Denial-of-Service (DoS) attacks. These findings underscored the necessity of strong security measures to ensure the confidentiality, integrity, and availability of V2I data, which is essential for Intelligent Transportation Systems (ITSs) [17]. Previous research further detailed threats to V2X communication, such as message spoofing, Sybil attacks, and Denial-of-Service (DoS) attacks, which could disseminate false information, disrupt traffic management systems, and compromise vehicle safety mechanisms [18].

Ibrahum et al. [19] categorized AV attack scenarios into environmental attacks, AV agent-based attacks, and environmental camouflage, using a safety taxonomy matrix to classify risks into Known/Safe, Known/Unsafe, Unknown/Unsafe, and Unknown/Safe areas. While the work focused on adversarial attacks and defenses, their categorical approach offered insights that guided the classification and categorization aspects of our data classification framework for AVs.

None of these past studies directly provided a concrete data classification framework; however, they offered essential insights. These included data sources, vulnerabilities, and attack vectors. These findings identified critical gaps, guiding the development of a robust framework that incorporates data origin, sensitivity levels, and usage patterns. By synthesizing this knowledge, our research proposes a comprehensive framework for data classification that addresses the unique needs of autonomous vehicles, ensuring secure and efficient operation.

3. Real-World Autonomous Vehicle Vulnerability Scenarios

Autonomous vehicles (AVs), which rely heavily on data-driven systems, are increasingly targeted by malicious cyber attacks. Understanding the scope and impact of these attacks on specific data types within AV environments is crucial for strengthening their security. In this section, we explore cyber threats targeting various data in AV environments and vulnerabilities that exist in AVs, drawing from recent instances of attacks along with attacks carried out by researchers in a simulated but real-world environment.

These real-world incidents in Table 1 vividly illustrate the vulnerability of every type of data within autonomous vehicles to cyber attacks, emphasizing the imperative of data classification as a fundamental defense. By systematically categorizing and organizing data according to importance and sensitivity, we establish a robust framework for preventing potential threats.

Table 1. AV vulnerability breach real-world incidents.

Attack On	Nature of Attack	Targeted Data
2022 TeslaMate Vulnerability Exploitation	Security experts exploited a weakness in TeslaMate to gain remote access to over two dozen Tesla vehicles [20].	Car’s API key, enabling actions like unlocking doors, starting the car, and accessing sensitive data.
2023 Jailbreaking Tesla’s Infotainment System	Jailbreak on Tesla’s infotainment system bypassing AMD-based hardware and Linux OS security features [21].	Software-locked features and system configurations, such as seat heater controls and vehicle settings.
2015 Jeep Cherokee Remote Takeover	Remote hack of a Jeep Cherokee’s entertainment system via Uconnect, gaining control over speed, brakes, and steering [22].	Vehicle control data transmitted over the internal network.
2016 Tesla Model S Remote Access	Remote breach of a Tesla Model S to modify mirrors, unlock the trunk, and activate brakes while moving [23].	Vehicle control data and diagnostic data.
2015 BMW ConnectedDrive Vulnerability	Exploitation of BMW ConnectedDrive system flaw to remotely unlock vehicle doors [24].	User authentication data and vehicle access data.
2019 Tesla Model 3 Navigation System Spoofing	Manipulation of Tesla Model 3 GPS signals to feed false positioning data [25].	GPS data.
2016 Nissan Leaf Remote Access	Exploitation of NissanConnect app vulnerability to access Nissan Leaf controls remotely [26].	User control data via mobile application.
2016 Volkswagen Key Fob Cloning	Wireless interception and cloning of Volkswagen key fob signals to unlock vehicles [27].	Key fob signal data.

4. Traditional Vehicle Environment Data and Sources

To understand the complexities of autonomous vehicle (AV) data, it helps to first look at the simpler data used in traditional vehicles. Traditional vehicles rely on basic datasets, providing a clear foundation for appreciating how much more advanced and intricate AV data have become. By comparing the two, we can see the enormous leap in data volume and complexity with AVs. This comparison highlights why precise data classification is essential to ensure robust cybersecurity in these advanced systems.

Table 2 outlines the various data types that traditional vehicles handle, showcasing the broad and specific information essential for their operation. Yet, the leap into self-driving car technology has significantly expanded the landscape of vehicle data. In the upcoming section, this study showcases how autonomous vehicles have introduced a whole new set of data complexities, stepping beyond the foundational data discussed here.

Table 2. Different data types along with their sources in traditional vehicles.

S.No.	Data Classification	Data Source	Specific Data Type	Functionality	Example	Format
i.	Operational Data	Engine control unit	Engine parameters	Monitors and adjusts engine operations	Engine RPM, temperature	Numeric values, dashboard indicators
ii.		Speedometer	Vehicle speed	Displays the current speed of vehicle	55 mph or 85 km/h, etc.	Analog/digital display
iii.		Fuel gauge	Fuel level	Indicates the amount of fuel present	Half tank or full tank or bar indicating fuel level	Analog/digital display
iv.		Battery management system	Battery health and charge level	Monitors the battery’s charge status and health condition	Readings such as 15.5 volts	Numeric value or indicator in dashboard
v.	Diagnostic Data	OBD-II ports	Diagnostic trouble codes (DTCs)	Identifies specific issues within the vehicle’s system	Indicator such as P0171—System too lean	Alphanumeric codes
vi.	Maintenance Logs	Service records	Records of vehicle servicing and repairs	Documents of vehicle maintenance history for upkeep and resale	Oil change at 2000 miles	Text records or numeric values
vii.	Safety and Security Data	Airbag system	Airbag status	Indicates the readiness of airbag system	Airbag ready	Dashboard indicator lights
viii.		Vehicle alarm system	Security status	Monitors unauthorized tampering and entry	Alarm armed	Light or sound alarm indicator
ix.		Tire pressure monitoring system (TPMS)	Tire pressure	Alerts to driver for under-inflated tires	32 psi, 35 psi	Numeric value or indicator in dashboard
x.	User interaction	HVAC controls	Temperature settings	User-set temperature control for vehicle interior	22 °C, 25 °C, 75 °F	Digital interface or manual dials
xi.		Audio system	Radio presets	Allows settings and selection of favorite stations	101.1 FM is preset	Touchscreen selection or buttons
xii.	Regulatory compliance data	Emission control system	Emission data	Monitor exhaust emissions to meet regulatory standards	Passed/failed emission test	Numeric values or text notifications
xiii.		Odometer	Mileage	Tracks vehicle total distance travelled	50,000 miles	Dashboard display of numeric value

5. Autonomous Vehicle Environment Data and Sources

Recognizing the diverse array of data sources and their associated security risks is crucial for safeguarding autonomous vehicles (AVs) against cyber threats. In this section, we identify multiple data sources, examine the corresponding data they produce, and analyze their roles in autonomous vehicle (AV) operation, highlighting their critical importance in ensuring smooth and secure functioning within AV networks.

5.1. Sensors

Sensors are the eyes and ears of self-driving cars, crucial for helping these vehicles understand and move through the world safely.

The sensors shown in Figure 1 collect a huge amount of information from all around the car, including the distance to nearby objects and the speed of surrounding vehicles. These data are highly varied, providing the car with everything it needs to navigate roads, avoid accidents, and interact smoothly with its environment. Each sensor has a specific role, gathering the particular types of data needed for the car to make smart decisions quickly, as depicted in Table 3 below.

Figure 1. Primary sensors’ integration in autonomous vehicle systems [28]. In the figure, LIDAR represents Light Detection and Ranging, GPS represents Global Positioning System, and RADAR represents Radio Detection and Ranging.

Table 3. Types of sensors and data produced.

S.No.	Sensor Type	Functionality		Data Obtained in AV Environment
i.	Vision camera	Utilized for environmental surveillance—capture detailed surroundings through light on a photosensitive surface via a lens, offering cost-effective means to identify obstacles and produce high-resolution images [8].	Gathers precise visual data of surroundings, such as traffic signals, road markings, and vehicles, crucial for analyzing complex scenarios, reading signs, and making informed decisions based on visual cues.	Visual imagery
ii.	Thermal camera		Identifies thermal patterns, essential for spotting humans and animals in poor-visibility conditions, including darkness, smoke, or fog.	Thermal imagery
iii.	Ultrasonic	Generates high-frequency sound pulses that bounce off objects; the sensor then measures the interval for these echoes to return and factors in temperature fluctuations to accurately gauge distances, enhancing autonomous vehicle navigation [9].		Echo timings and amplitude changes in sound wave data for proximity detection and environmental assessment.
iv.	Sonar (sound navigation and ranging)	Emits sound waves that rebound off objects back to the sensor, utilizing the echo’s travel time to ascertain distance [9].		Sound wave frequencies and echo timings for distance measurement.
v.	Yaw rate	Typically a piezoelectric gyroscopic sensor, employs the Coriolis effect to detect the vehicle’s rotation, pinpointing the angular discrepancy between its intended heading and actual motion, crucial for electronic stability control [9].		Measurements of angular velocity in degrees or radians per second, indicating the vehicle’s rate of rotation.
vi.	RADAR (Radio Detection and Ranging)	Employing the Doppler effect and beam-forming, RADAR sensors accurately identify obstacles’ distance, speed, and direction, excelling in various climates for adaptive cruise control and safety measures [9].		Object detection at long distances, relative velocity, and angle of objects in relation to the vehicle. Quantitative measurements of distance (m or km), speed (m/s or km/h), and angular position (degrees or radians).
vii.	LIDAR (Light Detection and Ranging)	Leverages infrared lasers and a rotating mirror to generate detailed environmental maps by reflecting light from surfaces, offering accurate 3D environmental data, effective in various weather conditions and with materials of semi-porous nature.		High-resolution spatial measurements and 3D mapping data. Point cloud data (PCD) with x, y, z coordinates and object intensity information, enabling detailed 1D, 2D, and 3D environmental and object mapping [8].
viii.	Wheel speed	Employing Hall effect sensors at each wheel to generate frequencies indicating wheel speeds; measuring and providing vital data for enhancing vehicle stability and control dynamics (crucial for ABS and cruise control) [9].		Velocity measurements in kilometers per hour (km/h) or miles per hour (mph) for each wheel, vital for stability control and dynamic adjustments.
ix.	Accelerometers (lateral/longitudinal)	Measure velocity fluctuations across the vehicle’s longitudinal and lateral axes, providing essential data for collision avoidance and vehicle dynamic management systems through precise quantification and analysis of vehicular motion and spatial orientation.		Acceleration data in directions, presented as meters per second squared (m/s²), essential for improving stability and responsiveness.
x.	Infrared (IR)	Detects heat emissions and converts them into thermal images, pivotal for spotting living beings like pedestrians and animals in low-visibility situations by highlighting temperature variations.		Detects heat emissions and converts them into thermal images, pivotal for spotting living beings like pedestrians and animals in low-visibility situations by highlighting temperature variations.

5.2. GPS

GPS in autonomous vehicles (AVs) is a sophisticated component that harnesses satellite signals to deliver comprehensive spatial data, as shown in Table 4, which is crucial for the vehicle’s navigation and decision-making processes. By triangulating signals from multiple satellites, the GPS sensor accurately determines the vehicle’s geographical location, elevation, direction, and speed. This process enables AVs to understand their position within a global context, crucial for mapping routes, adapting to changes in the environment, and ensuring accurate travel paths without the need for constantly updated physical maps [29].

Table 4. GPS data in AVs.

S.No.	GPS Data Type	Data Format	Description
i.	Locational	Decimal degrees	Provides precise longitudinal and latitudinal coordinates, pinpointing the vehicle’s exact global position. Transmitted in structured formats like JSON or XML to the navigation system, indicating the current location.
ii.	Velocity	Meters per second (m/s) or kilometers per hour (km/h)	By tracking changes in position over time, GPS furnishes speed data, offering insights into the vehicle’s current velocity. It is integrated into the AV’s control system and is often communicated through standardized data protocols like CAN messages or API calls in JSON or Protobuf format.
iii.	Directional	Degrees	GPS aids in determining the vehicle’s orientation, indicating its direction of movement. It is processed by the AV’s navigation system and transmitted in structured formats such as JSON or XML.
iv.	Timestamp	UTC (Coordinated Universal Time) format	Each GPS reading is accompanied by an accurate timestamp, crucial for seamlessly synchronizing data from diverse sources in real time. It is integrated into data packets alongside other sensor readings, often using standard time representation formats like ISO 8601, and transmitted through data exchange protocols such as MQTT or HTTP.

5.3. Diagnostic Data

Diagnostic data, as shown in Table 5, encompass information that reveals details about the vehicle’s functional state, condition, and any issues that might influence its efficiency or security. This information mainly originates from the vehicle’s onboard diagnostics (OBD) system, which is responsible for tracking diverse aspects and systems of the vehicle, such as the engine, transmission, electronics, and other essential parts.

Table 5. Diagnostic data in AVs.

S.No.	Diagnostic Data Source	Data Provided	Functionality		Format
i.	Onboard Diagnostic Systems (OBD-II)	Diagnostic trouble codes (DTCs)	Diagnostic trouble codes (DTCs) are standardized alphanumeric codes generated by a vehicle’s OBD-II system to swiftly identify and pinpoint specific operational issues across various systems like the engine, transmission, and safety features, facilitating quicker diagnostics and repairs.		Alphanumeric codes (e.g., P0301, indicating a cylinder 1 misfire)
		Live data	Data collected in real time from the vehicle’s internal monitoring, such as the heat levels of the engine, revolutions per minute (RPM), and data from the oxygen sensor.		Vehicle manufacturers use unique, proprietary formats to transmit data, yet this information can be retrieved and interpreted via standardized OBD-II scanners, converting it into easily understandable formats such as JSON or XML.
		Freeze-frame data	A snapshot of the engine’s conditions at the time a fault is detected, which includes vehicle speed, fuel trim, and engine load.
ii.	Electronic Control Units (ECUs)	Performance metrics	Information regarding the functioning and efficiency of the vehicle’s systems, including aspects like fuel injection timing, throttle positioning, and brake pressure.		Binary or Hexadecimal Signals for intra-vehicle communication, especially over CAN bus systems.
		System health	Data regarding the condition and functionality of the system managed by the ECU, encompassing fault codes and alerts.		Structured data formats (e.g., JSON, XML) for external communication with diagnostic equipment or for telematics transmissions.
		Operational data	Precise operational metrics and configurations, like air–fuel mixture ratios, engine timing adjustments, and the behavior of the anti-lock braking system (ABS).
iii.	Telematics devices	Vehicle usage data	Data on vehicle operation, including mileage, speed patterns, and idle times.	Mileage: Total distance traveled.	Structured data (JSON, XML) for vehicle usage and diagnostic information.
				Speed patterns: Vehicle’s speed over time.
				Idle times: Duration vehicle remains stationary with engine running.

5.4. User Input Data

The data input by occupants in autonomous vehicles (AVs) encompasses any information directly provided or communicated by them. This includes various interactions like preferences, adjustments to settings, manual inputs, and voice commands. Such inputs are vital for tailoring the driving experience, ensuring comfort, and, in certain situations, overriding autonomous functions for safety or preference purposes. Table 6 presents various types of user input data along with their sources, functionality, and examples.

Table 6. User input data in AVs.

S.No.	Data Source	Functionality	Specific Data Examples	Format
i.	Touchscreen interfaces	Input preferences, control entertainment systems, adjusting climate settings, navigation	Preferences for seat positions, mirror adjustments, climate control settings, navigation map inputs, entertainment system controls (e.g., playlist selection), etc.	Structured data formats (JSON, XML)
ii.	Voice command systems	Hands-free operation and control of the vehicle’s systems	Voice commands for navigation (e.g., “Navigate to work”), commands for phone calls (“Call Dad”), music track changes (“Play previous song”), etc.	Audio signals (processed by onboard systems or external services for speech recognition)
iii.	Physical controls	Direct control over specific functions using buttons	Manual input for air conditioning intensity, audio volume adjustments, emergency braking activation, driving mode selection (e.g., eco mode, sport mode), etc.	Binary signals (indicating on/off states, levels of adjustment)
iv.	Mobile applications	Remote interaction with the vehicle	Setting cabin temperature before entry, unlocking doors remotely, configuring navigation routes, adjusting vehicle settings (e.g., when the car starts based on schedule, lighting preferences), etc.	Structured data formats (JSON, XML) for communication between the app and vehicle’s systems

5.5. Connectivity Data

Connectivity data play a pivotal role in enhancing intelligent vehicle operations and interactions within the broader transportation ecosystem. These types of data, as shown in Table 7, enable communication between autonomous vehicles and various external entities, including other vehicles, infrastructure, networks, and pedestrians.

Table 7. Connectivity data in AVs.

S.No.	Data Source	Functionality	Specific Data Examples	Format
i.	Vehicle-to-Vehicle (V2V)	Allows AVs to share vital operational data to prevent collisions and optimize traffic flow.	Speed, direction, GPS coordinates, brake status, etc.	DSRC, Cellular V2X (C-V2X)
ii.	Vehicle-to-Infrastructure (V2I)	Provides AVs with real-time information on traffic conditions, road works, and infrastructure statuses.	Traffic signal timing, road condition alerts, infrastructure status, etc.	DSRC, C-V2X, Internet Protocol (IP)
iii.	Vehicle-to-Network (V2N)	Enables access to broader services such as real-time traffic management, weather updates, and online entertainment.	Traffic and weather updates, streaming content for infotainment systems, etc.	Cellular networks (LTE, 5G), Wi-Fi
iv.	Vehicle-to-Everything (V2X)	Enhances situational awareness by integrating data from multiple sources, supporting autonomous driving decisions.	Pedestrian movements, emergency vehicle alerts, environmental awareness data.	DSRC, C-V2X for direct communication; Cellular, Wi-Fi for network-based interactions
v.	Information exchange	Facilitates a broad exchange of data for improved situational awareness and operational efficiency of AVs.	Information exchanged with other vehicles, infrastructure, or networks.	Varies depending on system and network requirements, including DSRC, C-V2X, LTE, 5G, and Wi-Fi

All different V2 (Vehicle-to-Vehicle, Vehicle-to-Infrastructure, Vehicle-to-Network, etc.) systems have unique security threats; however, V2X technology addresses all of these challenges under a unified communication framework. As AV connectivity plays a pivotal role in the current transportation ecosystem, understanding the security threats associated with V2X technology is crucial for ensuring its safe and effective implementation. The primary security challenges for V2X include managing dynamic network topology, ensuring network scalability, addressing heterogeneity across global infrastructures, minimizing communication latency, prioritizing critical data, adapting to future platforms, preventing attacks on both users and systems, and maintaining user trust and privacy through advanced solutions like PKI, pseudonymization, and hybrid techniques [18].

6. Autonomous Vehicle Data Flow Overview

Before classifying data in autonomous vehicles (AVs), it is essential to understand how data flow through their core systems, i.e., Perception, Planning, Control, and Communication. This section shows how the integration of sensors, algorithms, and communication protocols enables AVs to interpret their environment, make decisions, and execute actions. Understanding this data flow establishes the foundation for exploring how data classification enhances security, protects sensitive information, and ensures reliable system performance.

Figure 2 depicts a typical layout of an autonomous vehicle system, highlighting key functions crucial for its operation. The Perception layer gathers data and interprets relevant information from the vehicle’s surroundings using sensors and V2X messages. It includes two parts: environmental perception and localization. Environmental perception identifies and categorizes surrounding objects like obstacles, road geometry, and signs using methods like Multi-Object Tracking and segmentation, with sensors such as LIDARs, cameras, and radars. Localization, or SLAM, builds and updates a map while tracking the vehicle’s position and orientation.

Figure 2. A typical AV system overview [30].

The Planning layer generates optimal paths and actions based on Perception’s data. It employs decision-making algorithms to navigate the vehicle safely and efficiently.

The Control layer executes the planned trajectories by controlling the vehicle’s actuators, ensuring it follows the desired path accurately.

Lastly, the Communication layer enables information exchange between autonomous vehicles and infrastructure, fostering cooperative behavior and enhancing traffic efficiency. This structured framework enables autonomous vehicles to perceive, plan, control, and communicate effectively, ensuring safe and reliable driving in diverse scenarios.

Figure 3 illustrates a multi-layered method through which an autonomous vehicle understands its environment. It begins with the collection of data via a variety of sensors, as presented in Figure 1. These sensors collect visual, spatial, and motion-related information, while the Road Network Definition File (RNDF) offers predefined routes for navigation. The collected data are then processed by specialized units: cameras identify road lanes, LiDAR delineates drivable areas, and radar monitors the velocity and position of nearby objects. Combined with accurate location data from GPS/INS and odometry, this information is processed by the pose estimator, which integrates the data to determine the vehicle’s exact location and direction. Based on this integration, a local map is continuously updated, which the vehicle utilizes for navigation.

Figure 3. Information integration in the Perception framework [31].

Regardless of how data traverses through the system, incorporating data classification at each stage is essential for maximizing security and operational efficiency. At the Perception stage, the immediate classification of incoming data by sensitivity is crucial. For instance, data from GPS and cameras should be considered highly sensitive, necessitating stringent encryption and access controls. As these data progress to the Planning and Control stages, their classification guides how they are processed and safeguarded, ensuring that critical data impacting vehicle functions remain protected. In the Communication stage, correct data classification is key to facilitating safe and secure communication with other systems like V2V and V2I, thereby preserving data integrity and confidentiality, which are vital for the reliable operation of AVs. Embedding data classification into the data flow process underscores the significance of robust data management for the effective and safe functionality of autonomous vehicles.

7. Data Classification Frameworks of Autonomous Vehicles

7.1. Based on Sensitivity

Classifying data based on sensitivity is crucial for determining the appropriate level of security and access controls. Sensitivity classification helps in prioritizing the protection of data according to its importance and potential impact on privacy, security, and operational integrity. The primary bases for classifying data according to its sensitivity include public, sensitive, highly sensitive, and critical data. This framework categorizes data by evaluating its purpose, usage, and the potential risks associated with exposure.

7.1.1. Public Data

This category comprises data that can be freely shared without significant privacy or security concerns. Public data in the framework encompass generic, non-identifiable information such as broad traffic patterns, environmental models, and aggregated usage statistics, which pose minimal privacy risks [32].

7.1.2. Sensitive Data

Data and information falling under this category could potentially compromise user privacy or reveal operational details if exposed. Sensitive data encompass data that can indirectly reveal user habits or geographic trends, such as identifiable landmarks, location-based data, and specific diagnostic alerts [33].

7.1.3. Highly Sensitive Data

This classification involves data with a substantial risk of privacy violation or operational interference if improperly disclosed. High-sensitivity data encompass directly identifiable information and data in the framework, such as license plates, advanced vehicle stability data, and health diagnostics, which can pose privacy or security risks if misused.

7.1.4. Critical Data

Representing the most sensitive category, critical data include information directly impacting personal safety, operational integrity, and security. Unauthorized access to this data could lead to severe privacy breaches, safety risks, and security vulnerabilities. Critical data encompass data such as personal, secure, or safety-critical information, including biometric identifiers, precise geolocations, and vehicle operational faults that, if compromised, could lead to severe harm [34].

The classification process evaluated every type of data collected by the sensors against these four categories, considering the functional purpose and potential risks associated with exposure. Each data type from every sensor was assessed for its intended application and potential impact if compromised, adhering to a validation process informed by scientific studies and regulatory guidelines. The validation process relied on published studies such as [32], which confirmed the minimal privacy implications of public data. Sensitive data classifications were grounded in research exploring the privacy risks of location-based and contextual data [33]. High-sensitivity data validation relied on studies highlighting the risks of identifiable data such as license plates or vehicle stability metrics [35]. Critical data classifications were supported by findings on the security and privacy challenges posed by personal and safety-critical data under regulations such as GDPR [34].

The novel classification table developed using this framework maps each sensor’s specific data types to these sensitivity levels, ensuring a use-case and importance-based process. This framework, grounded in the scientific literature and regulatory guidelines, establishes a robust foundation for managing data sensitivity in AV systems, enabling developers to implement targeted and effective data protection measures.

Classifying data based on sensitivity (Table 8) is indispensable in the current autonomous vehicle (AV) scenario for several compelling reasons. In the complex ecosystem of AVs, where vast amounts of data are constantly being collected, processed, and shared, the stakes for data security and privacy are exceptionally high. Sensitivity data classification enables stakeholders to implement a layered security approach, ensuring that the most critical data—be it related to vehicle operation, personal user information, or safety mechanisms—receives the highest level of protection. This helps in pinpointing which data require stringent encryption, who should have access to these data, and what kind of breach detection mechanisms are necessary.

Table 8. Sensitivity-based classification framework.

S.No.	References	Data Source	Specific Data	Data Classification on Sensitivity Basis
				Public	Sensitive	High	Critical
i.	[8,10,36]	Vision camera	Visual imagery	Traffic patterns, unidentifiable scenes	Landmarks, identifiable scenes	License plate numbers	Faces, linked personal data
ii.	[11,37]	Thermal camera	Thermal imagery	Environmental heat maps	Sensitive-area heat maps	Human and animal detection	Individual identification in secure areas
iii.	[9,10,38]	Ultrasonic sensors	Echo timings, amplitude	Generic proximity alerts	Specific proximity alerts	Close-range obstacle data	Detailed environmental mapping
iv.	[9]	Sonar	Sound wave frequencies	Broad object detection	Fine object detection details
v.	[9]	Yaw rate sensors	Angular velocity	Basic vehicle dynamics	Advanced stability data	Critical rollover risk indicators
vi.	[8,9,10,11]	RADAR	Detection, speed, direction	General object and traffic flow	Detailed traffic dynamics	Precise vehicle tracking	Highly accurate immediate surroundings
vii.	[8,10,11]	LIDAR	3D spatial data	Basic environmental models	Detailed environmental obstacle mapping	Precise 3D reconstructions
viii.	[9,39]	Wheel speed sensors	Velocity measurement			Wheel speed data
ix.	[40]	Accelerometers	Acceleration patterns	Basic movement analysis	Sudden movement events		Detailed handling and control data
x.	[28,41]	GPS	Location, speed, time	General route data	Precise location and speed	Historical route and preference data	Precise geolocation data
xi.	[42,43]	OBD-II	DTCs, lice data, freeze-frame data	General vehicle condition	Specific diagnostic alerts	Detailed vehicle health and diagnostics	Critical operational faults
xii.	[44]	ECUs	Performance metrics, system health, and operational data	Basic operational status	Performance warnings	Detailed performance diagnostics and configurations	Key security configurations and data
xiii.	[45]	Telematics devices	Vehicle usage data	Aggregate statistics	Individual usage data	Detailed driving patterns and locations	Personal habits and precise locations
xiv.	[46]	Voice command systems	Audio input signals	Generic commands	Custom commands		Identifiable voice prints and commands
xv.	[47]	Mobile applications	Remote interactions		Non-sensitive adjustments	Lock/unlock cabin temperature	Geolocation, personal settings
xvi.	[12,13,14,17,18]	V2V, V2I, V2N, V2X	Communications data	General traffic and infrastructure information	Traffic flow, infrastructure status	Personal data exchanges, specific route data	Emergency vehicle alerts, precise location data
xvii.		Information exchange	Shared data	General traffic information		Operational vehicle data	Sensitive operational and personal data
xviii.	[48]	Infrared sensors	Heat signatures and thermal images	Broad heat detection		Pedestrian detection in low visibility	Identifiable heat signatures in secure areas
xix.	[49]	Physical controls	Binary signals	Status indicators	Manual adjustments (volume, A/C)	Manual control overrides	Emergency activations and controls
xx.	[50]	Touchscreen interface	User inputs and settings	Basic settings	General preferences (media control)	Navigation preference	Saved personal and sensitive locations
xxi.	[51]	User profile	Personal settings, preferences	Basis user preferences	Detailed personal settings	User behavioral data	Complete profile with historical data

Moreover, in the event of a cyber attack, a clear understanding of data sensitivity allows for a rapid assessment of potential impacts, prioritization of responses, and effective mitigation of damage. Sensitivity classification not only safeguards the integrity and functionality of AV systems against malicious exploits, but also upholds the trust and confidence of users by protecting their privacy. In an era where data breaches can have dire consequences, ranging from personal privacy violations to life-threatening safety risks, the meticulous classification of data based on sensitivity is not just a security measure, it is a fundamental pillar supporting the safe advancement of autonomous vehicle technology.

7.2. Based on Usage

This study classifies autonomous vehicle (AV) data by its usage—into operational, analytical, and regulatory categories.

7.2.1. Operational Usage

Operational data are directly involved in the real-time operation and oversight of autonomous vehicles (AV).

7.2.2. Analytical Usage

Analytical data focuses on enhancing AV systems, optimizing vehicle performance, and improving user interactions. It involves incorporating machine learning models to refine decision-making, leveraging usage data to anticipate maintenance needs, and fostering continuous advancements in AV technology.

7.2.3. Regulatory Usage

This classification encompasses data essential for meeting legal and regulatory obligations, including incident logging for investigation, safeguarding user data, and adhering to traffic regulations, emphasizing the vital role of identifying and overseeing regulatory data to ensure alignment with legal mandates and safeguard the interests of both users and the broader community.

Having delineated the three principal usage categories—operational, analytical, and regulatory—we established a systematic approach to classify each autonomous vehicle (AV) data type. This approach is anchored in functional role analysis, which examines the purpose and timeframe in which each data source is utilized (i.e., immediate operation, long-term system improvements, or legal compliance). Building on the data sources identified in Section 5 of this paper, we mapped these sources and their respective data to the three usage categories by scrutinizing their real-world functions.

• Data essential for real-time control or critical to immediate vehicle operation are designated as operational data.
• Information primarily used for post-processing or long-term improvements is designated as analytical data.
• Datasets necessitated by legal, safety, or compliance requirements are deemed regulatory data.

After completing the initial mapping of data to the three usage categories, a literature review was undertaken to validate the role (primary usage) and urgency of each data source. This review confirmed whether the data in question were critical for immediate operational decisions, instrumental for post-processing and long-term analytical insights, or mandated by regulatory frameworks for compliance and legal accountability. Following the methodology described above, each data source was scrutinized based on the following:

i.

Immediate Impact on Vehicle Behavior: Data that inform instantaneous control decisions, such as sensor data for collision avoidance, were classified under operational usage.

ii.

Long-Term Insight Generation: Data used for offline machine learning, performance analysis, or predictive maintenance, such as aggregated sensor logs, were categorized as analytical.

iii.

Legal and Compliance Obligations: Data required for incident reporting, privacy compliance, emissions checks, or insurance documentation, such as event data recorders and audit logs, were classified under regulatory usage.

Classifying AV data based on use, as in Table 9, helps identify what data need the most protection. By understanding whether data are used for operating the vehicle, for analysis, or to comply with laws, risks can be better managed. This classification guides us in applying the right security measures to the right data, ensuring sensitive information is safeguarded and reducing the chances of cyber threats.

Table 9. Usage-based classification framework.

S.No.	Data Source	Specific Data	Data Classification Based on Usage			Primary Usage
			Operational	Analytical	Regulatory
i.	Vision camera	Visual imagery	✓	✓		Primarily operational for real-time navigation and obstacle detection, with analytical applications in traffic pattern analysis [8,10,36].
ii.	Thermal camera	Thermal imagery	✓	✓		Used operationally for detecting living entities in low visibility and analytically for environmental condition assessment [11,37].
iii.	Ultrasonic sensors	Echo timings, amplitude	✓			Operational use for proximity sensing and parking assistance [9,10,38].
iv.	Sonar	Sound wave frequencies	✓			Employed operationally for object detection and distance measurement underwater or in dense environments [9].
v.	Yaw rate sensors	Angular velocity	✓	✓		Operationally critical for stability control, with analytical use in vehicle dynamics analysis [9].
vi.	RADAR	Detection, speed, direction	✓	✓		Operationally used for collision avoidance and adaptive cruise control, with analytical applications in traffic flow optimization [8,9,10,11].
vii.	LIDAR	3D mapping data	✓	✓		Primarily operational for creating high-resolution environmental models, with analytical uses in roadway and infrastructure mapping [8,10,11].
viii.	Wheel speed sensors	Velocity measurement	✓	✓		Operationally used for anti-lock braking systems (ABSs) and traction control, with analytical applications in vehicle performance monitoring [9,39].
ix.	Accelerometers	Acceleration patterns	✓	✓		Used operationally for crash detection and vehicle stability, and analytically for driving behavior analysis [40].
x.	GPS	Location, speed, time	✓	✓	✓	Operationally vital for navigation and route planning, with regulatory implications for emergency response and compliance [28,41].
xi.	OBD-II	DTCs, lice data, freeze-frame data	✓	✓	✓	Provides operational diagnostics and vehicle health monitoring, with regulatory compliance in emissions testing [42,43].
xii.	ECUs	Performance metrics, system health, and operational data	✓	✓	✓	Operationally crucial for managing vehicle functions, with regulatory aspects tied to safety and emissions standards [44].
xiii.	Telematics devices	Vehicle usage data	✓	✓	✓	Operationally enables remote vehicle management, with analytical use for usage patterns and regulatory use in fleet management [45].
xiv.	Voice command systems	Audio input signals	✓	✓		Operationally facilitates hands-free controls, with analytical uses in customizing user experience [46].
xv.	Mobile applications	Remote interactions	✓	✓		Operationally allows for vehicle control remotely, with analytical use in personalization and user experience enhancement [47].
xvi.	V2V, V2I, V2N, V2X	Communications data	✓	✓	✓	Operationally essential for enhancing situational awareness and safety, with regulatory implications for traffic management [12,13,14,17,18].
xvii.	Information exchange	Shared data	✓	✓	✓	Used operationally for dynamic vehicle-to-environment interactions, with regulatory applications in data sharing standards compliance [12,13,14,18].
xviii.	Physical controls	Binary signals	✓			Primarily operational for immediate manual inputs affecting vehicle behavior [49].
xix.	Infrared sensors	Heat signatures and thermal images	✓	✓		Operationally used for detecting warm objects in poor visibility conditions, with analytical use in security applications [48,52].
xx.	Touchscreen interface	User inputs and settings	✓	✓		Operationally enables user customization of vehicle settings, with analytical applications in user preference learning [50].
xxi.	User profile	Personal settings, preferences		✓	✓	Analytically used to enhance user experience, with regulatory aspects concerning data privacy [51].

7.3. Based on the Overall Sensitivity of the Data Source

In the ongoing development of autonomous vehicle (AV) technologies, precise management and understanding of the collected data are imperative. A systematic classification of data based on its sensitivity is essential for preventing privacy infringements and mitigating cybersecurity threats. By categorizing data into four distinct levels, i.e., public, sensitive, highly sensitive, and critical, appropriate security measures can be tailored to each level. This stratification not only optimizes the allocation of security resources, but also ensures that the confidentiality and integrity of the data are preserved according to the data’s relative importance and the severity of potential risks.

To devise this classification, we conducted a comprehensive review of the existing literature on attack vectors in AV systems, examining both specific points of vulnerability and the consequences of potential breaches. By analyzing past incidents and theoretical threats discussed in academic and industry research, we identified how each data source could be exploited and the extent of potential harm. The analysis considered the nature of the attack, the attack surface vector, and how attacks on it affect AV systems, including whether the result halts the system, threatens life, breaches privacy, or causes simple inconvenience. Drawing upon these findings, we categorized the data sources into four key tiers of sensitivity. Each tier reflects both the likelihood of an attack and the degree of potential damage—ranging from the exposure of operational details to critical risks that could compromise vehicle safety or result in significant privacy violations.

In Table 10, we have categorized the primary data sources for AVs as detailed in Section 5, assigning each to the most appropriate sensitivity category. While acknowledging that some data sources may generate information at various sensitivity levels, this classification primarily focuses on the highest level of risk associated with the data if it were compromised. This methodical approach aids in prioritizing security efforts and safeguarding sensitive information effectively.

Table 10. Source-based classification framework.

S.No.	Data Source	Rationale for Sensitivity Level Classification	Sensitivity Level
i.	Vision camera	Vision sensors collect comprehensive visual data, which often contain identifiable elements like faces or vehicle registration plates. Unauthorized access to this information could result in privacy violations and the misuse of personal data. Even minor manipulations to the visual feed, such as painting inconspicuous lines on the road, can radically alter an end-to-end driving model’s perception and steering decisions, thereby confirming the high sensitivity of the vision camera to adversarial inputs [15]. Furthermore, research has shown that attacks on the forward-looking camera (e.g., laser blinding or spoofing) can severely compromise safety-critical functions like lane-keeping and traffic sign recognition. This sensor’s data are deemed highly sensitive [16].	Highly sensitive
ii.	Thermal camera	Thermal cameras capture heat patterns that can pinpoint human presence or actions, particularly in situations with limited visibility. Although they do not directly disclose identities, the way they are used can lead to privacy issues if handled improperly. It is highlighted in studies by researchers that manipulating the thermal feed—by exploiting heat signatures or patterns—can disclose personal information (e.g., human presence) and undermine safety-critical decisions in autonomous vehicles [53].	Sensitive
iii.	Ultrasonic sensors	Ultrasonic sensors gather precise data on proximity, which can be analyzed to deduce the operational habits and actions of autonomous vehicles (AVs). While these data are not personal, they can expose critical details about the strategies, operations, and routes of the vehicles. Jamming and spoofing can severely disrupt short-range obstacle detection. For instance, researchers have proved that by positioning a malicious transmitter a few meters from the vehicle and emitting continuous ultrasonic noise in the 40–50 kHz range, attackers can blind the parking sensors so that the system fails to detect real obstacles, thus risking collisions during low-speed maneuvers [16].	Sensitive
iv.	Sonar	Sonar systems, by capturing detailed echo information from the environment, can potentially chart areas in ways that expose secure sites or sensitive operational configurations if the data were to be compromised. Because reliable short-range obstacle detection is essential for parking and low-speed maneuvers, the authors show that by continuously emitting ultrasonic noise in the 40–50 kHz band or injecting carefully timed echo-like pulses to cause distance misreading (failing to detect real obstacles or introducing false ones), SONAR-based sensors (similar to ultrasonic/parking sensors) are ‘sensitive’ in the AV sensor security framework [16].	Sensitive
v.	Yaw rate sensors	These sensors primarily record data concerning the vehicle’s angular velocity, which is crucial for stability control, but has little direct impact on privacy or security under typical circumstances. As demonstrated by researchers in [54], the MEMS gyroscope (functionally serving as a yaw rate sensor) fundamentally measures the vehicle’s angular velocity to maintain stability control, and under typical conditions, it poses minimal direct concerns for privacy or security.	Public
vi.	RADAR	RADAR systems gather information on the distance and speed of objects, which could be used to monitor the movements of autonomous vehicles or interfere with object detection systems, thus compromising operational safety and integrity. Radars are seen to be prone to jamming and spoofing attempts: in the cited research, researchers demonstrated that injecting spurious signals into the 76–77 GHz band can overwhelm detection algorithms and disrupt crucial functionalities like adaptive cruise control and collision avoidance, thereby classifying radar data as sensitive [16].	Sensitive
vii.	LIDAR	LIDAR produces accurate 3D models of the AV’s surroundings, potentially encompassing critical geographic and infrastructure details. Researchers highlight that LiDAR can be jammed, blinded, or fed spurious laser pulses, causing the system to perceive ghost objects (replayed echoes) or miss real hazards, effectively undermining its 3D mapping of the environment [55]. If accessed without authorization, these data could enable breaches of physical security or targeted disruptions of autonomous vehicle navigation systems.	Highly sensitive
viii.	Wheel speed sensors	According to researchers, wheel speed sensors primarily provide essential operational data for vehicle dynamics without revealing sensitive personal or location information, thus classifying them as public data, although they are vulnerable to spoofing attacks that can disrupt safety systems like ABS [39]. Hence, this sensor delivers operational information like wheel speed, which is crucial for understanding vehicle dynamics but generally lacks sensitive details unless combined with additional data to deduce location or behavioral patterns.	Public
ix.	Accelerometers	Accelerometers capture acceleration data, which are mainly used in vehicle dynamics and control systems. Accelerometers are shown to be prone to acoustic spoofing, where attackers inject sound waves at the sensor’s resonant frequency (e.g., via speakers or transducers) to produce false acceleration readings that disrupt the vehicle’s navigation and control [55]. These data, if compromised, are not typically sensitive, but could become so if combined with other sensor data on driving patterns or routes.	Public
x.	Infrared	Infrared sensors play a vital role in detecting thermal differences, aiding in the identification of living organisms under diverse conditions. Infrared sensors have a critical role in enabling key autonomous functionalities, such as traffic signal following and lane-keeping, which are indispensable for the safe and efficient operation of autonomous vehicles, and hence are categorized as sensitive [52]. If not properly safeguarded, these data could be utilized for surveillance activities by malicious parties.	Sensitive
xi.	GPS	GPS data inherently impact user privacy due to their accuracy in pinpointing locations. In [55], the authors illustrate how GPS—being unauthenticated by design—can be jammed or spoofed with stronger, bogus signals. This is a particularly critical vulnerability since miscomputations of vehicle location undermine key autonomous driving decisions and cascade into further safety risks. If accessed without authorization, GPS information can facilitate real-time tracking and substantial breaches of privacy, underscoring the necessity for robust security measures.	Critical
xii.	OBD-II	Diagnostics provide comprehensive data on a vehicle’s operational condition and any malfunctions. Unauthorized access to this information could expose specific performance vulnerabilities, thereby constituting a security threat. The analysis conducted by researchers reveals that wireless OBD-II dongles are a pervasive security weakness in Automotive IoT ecosystems, and the exposure of detailed diagnostic data and the ability to manipulate vehicle functions without robust authentication mechanisms significantly heighten the risk of both privacy breaches and physical safety threats in autonomous vehicles [56].	Sensitive
xiii.	ECUs	Electronic Control Units (ECUs) regulate vital vehicle functionalities such as engine management and braking systems. Research paper [44] highlights the sensitivity and critical importance of Electronic Control Units (ECUs) in autonomous vehicles by detailing their integration with sensors and actuators to ensure optimal performance, efficiency, and safety. If ECU data are compromised, it could result in unauthorized control over these operations, presenting direct risks to the safety of passengers.	Highly sensitive
xiv.	Telematics devices	Telematics devices manage extensive datasets encompassing location, driver behavior, and vehicle utilization patterns, and the compilation of such data introduces significant privacy and security challenges, requiring robust protective measures, thereby making them highly sensitive [45].	Highly sensitive
xv.	Voice command systems	Voice command systems handle voice commands and may unintentionally record sensitive personal discussions or commands. Researchers demonstrate that voice command systems in autonomous vehicles are highly sensitive because they can be exploited through hidden voice commands embedded in white noise or ultrasound frequencies, enabling unauthorized control and the inadvertent recording of sensitive personal discussions, which underscores the critical need for robust security protocols to prevent eavesdropping and the misuse of captured data [57].	Sensitive
xvi.	Mobile applications	Mobile applications directly connect to autonomous vehicles’ systems and users’ personal devices, accessing a broad spectrum of personal and operational data. This connectivity positions them as prime targets for cyber-attacks, which aim to extract personal information or gain control of vehicle functionalities. According to researchers, mobile applications connected to autonomous vehicles are highly sensitive as they can be exploited through malicious applications, such as compromised proprietary apps in BMW’s ConnectedDrive, to access personal data or control vehicle functions, thereby necessitating robust security protocols to prevent eavesdropping and misuse of the captured data [58].	Highly sensitive
xvii.	Vehicle-to-Vehicle (V2V)	V2V communication enables the transmission of operational data among vehicles, including sensitive details related to vehicle dynamics and strategic operations. Vehicle-to-Vehicle (V2V) communication is highly sensitive in autonomous vehicle environments due to its crucial role in traffic safety and the extensive attack surfaces it presents, including vulnerabilities in Dedicated Short-Range Communications (DSRCs) and IEEE 802.11p protocols that could be exploited to disrupt traffic management systems, thereby necessitating robust security measures—such as authenticated and encrypted connections—to protect against cyber attacks that could manipulate vehicle functions and compromise the integrity of Intelligent Transportation Systems [13].	Highly sensitive
xviii.	Vehicle-to-Infrastructure (V2I)	V2I communication shares data with traffic management and infrastructure systems, potentially involving sensitive details about traffic flows and infrastructure conditions. Researchers have highlighted the critical importance of securing Vehicle-to-Infrastructure (V2I) communications, which share sensitive traffic and infrastructure data, by identifying vulnerabilities such as Man-in-the-Middle (MitM) attacks, replay attacks, tampering, and Denial-of-Service (DoS) attacks, thereby underscoring the necessity of robust security measures to ensure the confidentiality, integrity, and availability of V2I data to maintain the safety and efficiency of Intelligent Transportation Systems (ITSs) [17]. Safeguarding this information is essential to preserve the integrity of operations.	Sensitive
xix.	Vehicle-to-Network (V2N)	V2N communication participates in extensive network communications that reach beyond the individual vehicle, thereby increasing exposure to a variety of cyber threats. Vehicle-to-Network (V2N) communications are highly sensitive because, as [59] demonstrates, they share critical traffic and infrastructure data that are vulnerable to specific attacks such as frame injection, replay attacks, and Denial of Service (DoS), which can result in the unauthorized control of vehicle functions, the theft of drivers’ private information, and the disruption of Intelligent Transportation Systems (ITSs), thereby necessitating robust security measures to ensure the confidentiality, integrity, and availability of V2N data.	Sensitive
xx.	Vehicle-to-Everything (V2X)	V2X communication facilitates extensive data interactions among vehicles, infrastructure, and other connected entities, creating a sophisticated network. Vehicle-to-Everything (V2X) communication in autonomous vehicle environments is highly sensitive due to its susceptibility to attacks such as message spoofing, Sybil attacks, and Denial-of-Service (DoS) attacks, which can lead to the dissemination of false information, the disruption of traffic management systems, and the compromise of vehicle safety mechanisms, ultimately resulting in increased accident rates, a loss of user privacy, and the degradation of Intelligent Transportation Systems’ (ITSs’) integrity [18].	Highly sensitive
xxii.	Physical controls	Physical controls incorporate user input via manual interfaces such as the steering wheel, brake, and accelerator pedals. Typically, the data generated from these controls do not include sensitive information and are classified as public. However, when these physical controls are integrated with security systems capable of overriding operational commands for safety purposes, the associated data become sensitive due to the potential implications for vehicle safety and user privacy.	Public
xxiii.	Touchscreen interface	The touchscreen interface serves as a direct conduit for user interaction, enabling the input of preferences and critical settings. This is classified as sensitive because it consolidates the control of critical systems such as ADAS and IVIS, relies on capacitive technology prone to errors and environmental interference, lacks robust tactile feedback to prevent accidental activations, and serves as a single point of vulnerability that, if compromised, could grant unauthorized access to safety-critical and connected vehicle functions, posing significant security risks [50].	Sensitive

Every data source identified and tabulated in Table 10 is essential for the operation and functionality of autonomous vehicles (AVs), and classifying these sources based on their sensitivity is crucial for implementing the right security measures.

The proposed framework not only establishes a foundation for developing new security measures, but also enhances the adaptability of existing systems by addressing inter-disciplinary challenges in autonomous vehicle safety. For instance, Auto-CIDS, developed by Sorkhpour et al. [60], employs Deep Reinforcement Learning (DRL) and unsupervised algorithms to autonomously detect threats like Denial-of-Service (DoS), fuzzy, and spoofing attacks. Similarly, Anthony et al. [61] developed a high-accuracy IDS for autonomous vehicles using non-tree-based machine learning techniques, achieving up to 99% accuracy on real-world datasets to address threats like Denial-of-Service and spoofing attacks. While these studies focused on intrusion detection, their work aligns with our proposed data classification framework. Integrating a robust data classification framework could further enhance the ability to prioritize critical data, optimize resource allocation, and strengthen real-time threat detection in dynamic vehicular networks.

Koopman and Wagner [62] highlight the complexity of ensuring AV safety due to the need to validate adaptive systems and manage cross-disciplinary safety concerns, such as resilience in unstructured environments and fail-over mission planning. Incorporating this data classification framework into these safety measures can further refine such systems by enabling the prioritization of critical data, thereby optimizing response strategies and fortifying real-time decision-making against dynamic cybersecurity threats.

This systematic method improves the cybersecurity stance of AV systems and helps stakeholders focus their security efforts, ensuring that the most sensitive data are protected with the most robust measures to effectively reduce potential risks. Such classifications lay the groundwork for a robust security framework that supports the dependable and secure functioning of autonomous vehicles.

8. Conclusions

Data classification in AVs is required as a foundational step toward achieving a harmonious balance between innovation and security. It serves as a critical mechanism for identifying and prioritizing data according to its sensitivity and usage, ensuring that the most critical information is accorded the highest level of protection. This classification process is instrumental in mitigating the risks associated with data breaches, cyber attacks, and unintended privacy violations. By establishing clear demarcations between different types of data, stakeholders can implement customized security measures, comply with regulatory requirements, and foster public trust in AV technology.

In this study, we proposed a novel data classification framework designed to categorize AV data into meaningful brackets, such as public, sensitive, highly sensitive, and critical data. The introduced data classification framework, which categorizes AV data into public, sensitive, highly sensitive, and critical brackets based on sensitivity, usage, and source, is the key result of this study. Categorizing data on different bases is vital as AVs become more integrated into our daily lives, carrying an ever-increasing load of sensitive information. This ensures that every piece of information is treated with the highest regard based on its importance and vulnerability. Also, instead of treating every single piece of data individually and creating separate security measures for each, this classification framework groups similar types of data into a singular bracket. This approach simplifies the development of security measures by enabling a group rather than individualistic treatment of data, enhancing both efficiency and practicality. By focusing efforts on the most sensitive and vulnerable data categories, this framework provides a structured pathway for mitigating the risks associated with data breaches, cyber attacks, and privacy violations.

Looking ahead, there are several opportunities to expand upon this foundational framework to address emerging challenges and evolving technologies. Validation through simulations and real-world applications is a crucial next step. Applying the framework in realistic AV environments using testbeds or simulation platforms will help assess its practical effectiveness and robustness. Analyzing past cybersecurity incidents, such as the Tesla and Jeep attacks, can provide a tangible basis for evaluating its ability to address specific vulnerabilities. Additionally, quantitative assessments through simulation-based testing can offer critical insights, strengthening the framework’s applicability and showcasing its potential in mitigating security risks across AV systems.

The integration of machine learning and emerging technologies offers promising avenues for further development. Machine learning algorithms can dynamically classify data, enabling real-time adaptability to evolving threats and operational contexts in complex AV ecosystems. Such integration would enhance scalability and ensure the framework remains robust in addressing new challenges. Similarly, as technologies like 5G networks and quantum-resistant cryptography gain prominence, the framework must evolve to accommodate their unique security implications. Research in this area will ensure the framework remains forward-looking, aligning with the technological advancements shaping next-generation AV systems.

By addressing these future directions, this framework can evolve into a comprehensive solution capable of safeguarding privacy, enhancing vehicle reliability, and fostering trust in autonomous technologies, paving the way for a secure and connected future. This framework is a step toward that vision: a world where technology moves us forward with confidence to data security.