Analysis and Comparative Study of Signalized and Unsignalized Intersection Operations and Energy-Emission Characteristics Based on Real Vehicle Data

: With the development of the economy, urban road transportation has been continuously improved, and the number of motor vehicles has also increased signiﬁcantly, leading to serious energy consumption issues. As critical nodes in the urban road transportation network, intersections have become a focal point of research on vehicle energy consumption. To investigate whether trafﬁc signal lights affect fuel consumption and emissions, this study analyzed the operating characteristics, fuel consumption, and emissions of intersections with and without trafﬁc signal lights using real-world vehicle data. The data from the INTERACTION dataset for both signalized intersection VA and unsignalized intersection MA are used in the study, with a time duration of 3200 s. The VT-micro energy consumption and emissions model was applied to calculate and comprehensively analyze the vehicle ﬂow, fuel consumption, and emissions. Additionally, the study compared the fuel consumption and emissions for different driving scenarios, including straight through, left turn, right turn, and U-turn, within a single trafﬁc signal cycle. The results revealed that at signalized intersections, the average fuel consumption per vehicle was 26.54 L/100 km, NO x emissions were 68.76 g/100 km, and CO 2 emissions were 61.07 g/100 km. In contrast, at unsignalized intersections, the average fuel consumption per vehicle was 46.88 L/100 km, NO x emissions were 149.26 g/100 km, and CO 2 emissions were 107.16 g/100 km. The study indicated that for trafﬁc volumes between 50 and 103 vehicles per 100 s, signalized intersections demonstrated better fuel consumption and emission performance than unsignalized intersections. Signalized intersections could accommodate larger trafﬁc volumes and provide enhanced trafﬁc safety. In conclusion, the ﬁndings of this study are important for urban trafﬁc planning and environmental policies. They provide a scientiﬁc basis for reducing fuel consumption and emissions and improving road trafﬁc efﬁciency. Due to the advantages of signalized intersections in terms of energy consumption and emissions, future urban trafﬁc planning should consider more signal light controls to achieve energy savings


Introduction
The seriousness of environmental pollution has attracted global attention [1][2][3].Climate change, air pollution, and water pollution have become increasingly severe issues [4], forcing governments worldwide to take proactive measures to promote energy conservation and emission reduction.Particularly, petroleum consumption and tailpipe emissions from motor vehicles are significant contributors to environmental pollution [5,6], profoundly impacting air quality and human health [7].Furthermore, with the continuous growth in the number of motor vehicles, their energy consumption has also dramatically increased [8].The energy consumption issue of motor vehicles has become a critical challenge that is difficult to address in urban road traffic systems [9].To tackle this challenge, many countries and cities have been formulating and implementing various policies and measures to reduce the energy consumption and tailpipe emissions of motor vehicles, driving forward the process of energy conservation and emission reduction.
In urban road traffic networks, intersections are one of the key research areas for vehicle energy consumption and emissions.Intersections, due to their unique geographical locations and traffic organization characteristics, often lead to frequent acceleration, deceleration, and frequent stops of vehicles [10].These operational features make the issue of vehicle energy consumption and emissions at intersections more prominent, becoming a crucial focus for optimizing traffic operations and implementing environmental protection measures.In previous research, many scholars have focused on the energy consumption and emissions issues of motor vehicles at intersections.However, for the study of signalized intersection, most studies have been concentrated on topics such as eco-driving strategies at signalized intersections [11][12][13] and the optimization of traffic signal timing [14,15].For instance, Ren et al. [16] developed the CVIS intersection control model based on traffic efficiency and vehicle energy consumption.Li et al. [17] proposed an optimized speed-trajectory control method based on braking energy recovery efficiency to reduce energy consumption caused by frequent braking at signalized intersections.Wen et al. [18] proposed an optimal control method for connected and automated vehicles to pass through signalized intersections, aiming to reduce energy consumption in mixed traffic scenarios with conventional vehicles and connected and automated vehicles.Yan et al. [19] optimized traffic signal-control strategies according to the spatio-temporal characteristics of different traffic scenarios to alleviate urban traffic congestion.In addition, the ecological traffic concept is integrated into the traffic signal control, aiming at reducing traffic exhaust emissions.Boukerche et al. [20] explored traffic signal control through ecological driving technology to improve vehicle fuel efficiency.As for the study of unsignalized intersections, the current research focuses on the decision-making based on game theory [21][22][23] and the establishment of interactive behavior model between vehicles and pedestrians [24,25] without studying vehicle energy consumption and emissions.The original intention of setting traffic lights at intersections is to improve traffic efficiency and ensure traffic safety more effectively.Nevertheless, there have been no studies to explore whether the introduction of traffic lights under similar traffic flow conditions will have a positive impact on environmental protection, and there is a lack of comparative studies on energy consumption and emissions between signalized and unsignalized intersections, as shown in Table 1.

Signalized Intersection Unsignalized Intersection
Previous research Eco-driving strategies [11] Decision-making based on game theory [21,22] Optimization of traffic signal timing [14] Establishment of interactive behavior model between vehicle and pedestrian [24,25] Research gaps There have been no studies to explore whether the introduction of traffic lights under similar traffic flow conditions will have a positive impact on environmental protection, and there is a lack of comparative studies on energy consumption and emissions between signalized and unsignalized intersections.
Energies 2023, 16, 6235 3 of 24 Therefore, studying the energy consumption and emission characteristics of vehicles at intersections and exploring the impact of traffic signal lights on vehicle energy consumption and emissions can help identify solutions to reduce pollution and enhance traffic operational efficiency.This study aims to conduct a comparative analysis of energy consumption and emissions between signalized and unsignalized intersections, which can further aid in understanding the influence of traffic signals on vehicle energy consumption and emissions.The findings of these research efforts hold significant implications for urban traffic planning and environmental policies, providing a scientific basis for reducing traffic energy consumption, mitigating environmental pollution, and enhancing road traffic efficiency.
In the extraction of information such as vehicle speed and position from real vehicle data, multiple algorithms will be involved while simultaneously introducing errors and error accumulation.In data-driven analytical research, this aspect becomes particularly critical, and previous studies extensively explore this domain.Xia et al. [26] proposed a comprehensive automated driving system data acquisition and analytics platform, providing support for trajectory extraction and evaluation for connected automated vehicle.By leveraging deep-learning-based object detection and multi-object tracking algorithms, this platform achieved cooperative perception fusion and fine trajectory reconstruction through post-processing methods.Additionally, the pivotal role of localization was underscored by integrating inertial dead reckoning with 3D LiDAR-based map matching, showcasing the method's robustness against environmental uncertainties and sensor noise, which is verified through urban experiments [27].The pursuit of precise vehicle state estimation continued with a novel consensus-based algorithm introduced by Xia et al. [28], enhancing observability and accuracy for sideslip angle and heading estimation.This algorithm synthesized vehicle kinematics and dynamics, further heightening accuracy and observability in dynamic scenarios.Liu et al. [29] introduced a kinematic-model-based method for vehicle slip-angle estimation, seamlessly merging data from GNSS and IMU sources.Collectively, these studies advanced our comprehension of data processing, localization, and dynamic control.The INTERACTION real vehicle dataset utilized in this study has undergone video stabilization, alignment, detection, data association, tracking, and smoothing processes [30], ensuring data validity and reliability, providing a robust foundation for this analysis.
In summary, real-world vehicle data from the INTERACTION dataset is used, specifically focusing on data from two types of intersections: signalized intersection (referred to as VA) and unsignalized intersection (referred to as MA).The Virginia tech microscopic (VT-Micro) energy consumption and emission model is employed to perform calculations, allowing for a comprehensive analysis of vehicle flow, fuel consumption, and emissions.Furthermore, a comparison of fuel consumption and emissions is conducted for different operational scenarios within a single cycle, including straight-through, left-turn, right-turn, and U-turn movements.
The paper is organized as follows: Section 2 introduces VT-Micro energy and emission model and INTERSECTION dataset.In Section 3, the total operation characteristics and fuel consumption between signalized and unsignalized intersections are analyzed.In Section 4, one cycle operation characteristics and fuel consumption between signalized and unsignalized intersections are analyzed.Finally, the conclusions of this paper are drawn in Section 5, as shown in Figure 1.

VT-Micro Energy and Emission Model
The VT--Micro energy and emission model is a microscopic dynamic emission and fuel consumption calculation model obtained through the application of linear regression [31].It was proposed by Kyoungho Ahn and Hesham Rakha et al., based on fuel consumption data obtained from nine small cars using chassis dynamometers in a laboratory setting [32].This model considers vehicle speed and acceleration as variable parameters to calculate emissions and energy consumption for each vehicle.Subsequently, the scope of data collection was expanded from nine small passenger cars to include a total of 60 small cars and trucks [33].Cluster analysis techniques were employed to obtain the operating states and energy consumption data for these vehicles, resulting in refinements to the calculation formula of VT-Micro energy and emission model.While the theoretical energy consumption and emission values derived from the VT-Micro model may exhibit some discrepancies from actual values, the trends in energy consumption it reflects are generally consistent with empirical observations.Hence, the VT-Micro energy and emission model is used to conduct a comparative analysis of energy consumption and emissions at signalized and unsignalized intersections.
The basic form of the VT-Micro model is shown as Equation (1).
where, MOEe is the instantaneous energy consumption rate for the nth car.The unit is ml/s.vn is the instantaneous speed of the nth car and the unit is km/h.an is the instantaneous acceleration of the n th car, and the unit is km/h/s.i and j are the power of velocity and acceleration, respectively. , is the correlation regression coefficient when the acceleration is positive value and  , is when the acceleration is negative value.The total fuel consumption and emissions of the n th vehicle in the time T period are respectively recorded as Efuel, ENOx and ECO2, and the specific calculation formula is as shown in Equation (2):

VT-Micro Energy and Emission Model
The VT-Micro energy and emission model is a microscopic dynamic emission and fuel consumption calculation model obtained through the application of linear regression [31].It was proposed by Kyoungho Ahn and Hesham Rakha et al., based on fuel consumption data obtained from nine small cars using chassis dynamometers in a laboratory setting [32].This model considers vehicle speed and acceleration as variable parameters to calculate emissions and energy consumption for each vehicle.Subsequently, the scope of data collection was expanded from nine small passenger cars to include a total of 60 small cars and trucks [33].Cluster analysis techniques were employed to obtain the operating states and energy consumption data for these vehicles, resulting in refinements to the calculation formula of VT-Micro energy and emission model.While the theoretical energy consumption and emission values derived from the VT-Micro model may exhibit some discrepancies from actual values, the trends in energy consumption it reflects are generally consistent with empirical observations.Hence, the VT-Micro energy and emission model is used to conduct a comparative analysis of energy consumption and emissions at signalized and unsignalized intersections.
The basic form of the VT-Micro model is shown as Equation (1).
where, MOE e is the instantaneous energy consumption rate for the nth car.The unit is mL/s.v n is the instantaneous speed of the nth car and the unit is km/h.a n is the instantaneous acceleration of the nth car, and the unit is km/h/s.i and j are the power of velocity and acceleration, respectively.K e i,j is the correlation regression coefficient when the acceleration is positive value and K e i,j is when the acceleration is negative value.The total fuel consumption and emissions of the nth vehicle in the time T period are respectively recorded as E fuel , E NO x and E CO 2 , and the specific calculation formula is as shown in Equation ( 2): Energies 2023, 16, 6235 where, L n is the distance traveled by the nth car in the time T period.E e is the total fuel consumption or emission, in which the unit of fuel consumption E fuel is L/100 km, the unit of NO x emission E NO x is g/100 km, and the unit of CO 2 emission E CO 2 is kg/100 km.In 2014, Li et al. [34], based on the VT-micro model studied by Ahn et al., used the vehicle trajectory data in NGSIM (the main source of the data was the measured vehicle data of Los Angeles Highway 101 on 15 June 2005, 7:50-8:35 a.m.) to further fit the parameters of the model.The correlation regression coefficients corresponding to fuel consumption, NO x emissions, and CO 2 emissions were obtained, respectively, as shown in Tables 2-4.Using Equations ( 1) and (2), combined with the real-time speed and acceleration of the vehicle, the real-time fuel consumption and emission value of each vehicle can be calculated.

Data Introduction
The INTERSECTION dataset is a new dataset of naturalistic vehicle trajectories recorded at German intersections [36].In the dataset, intersection locations with and without traffic signals are screened.By comparing the road geometries and traffic flow, two locations are selected for the study: an unsignalized intersection named "USA_Intersection_MA" Energies 2023, 16, 6235 6 of 24 (hereafter referred to as MA) and a signalized intersection named "TC_Intersection_VA" (hereafter referred to as VA).The animation length and number of vehicles recorded in the two scenes in the dataset are shown in Table 5.The maps are shown in Figure 2.  [36].In the dataset, intersection locations with and without traffic signals are screened.By comparing the road geometries and traffic flow, two locations are selected for the study: an unsignalized intersection named "USA_Intersec-tion_MA" (hereafter referred to as MA) and a signalized intersection named "TC_Inter-section_VA" (hereafter referred to as VA).The animation length and number of vehicles recorded in the two scenes in the dataset are shown in Table 5.The maps are shown in Figure 2.  The signalized intersection has a main road with five lanes and six lanes, and a minor road with three lanes.In contrast, the unsignalized intersection has a main road with five lanes, which subsequently reduces to four lanes in the northbound direction, and a minor road with three lanes.The road geometries are generally similar, but the signalized intersection has a higher traffic volume.The signalized intersection was captured by a fixed camera within the recording range as indicated by the box outline in Figure 2. To facilitate a better and consistent comparison of the characteristics between signalized and unsignalized intersections, the internal area of the unsignalized intersection captured by a drone is also selected.The area does not include the road section leading to the intersection before entering it.
The file "DR_USA_Intersection_MA" consists of 22 Excel data sheets, with each sheet recording approximately 300,800 milliseconds, equivalent to 5 min.However, the file "TC_BGR_Intersection_VA" contains four Excel data sheets, each recording 899,900 milliseconds, which corresponds to 15 min.Each Excel data sheet primarily includes information such as track ID, vehicle types, vehicle sizes, current positions, current velocities, and orientations, as shown in Table 6.A partial data display is presented in Table 7.The signalized intersection has a main road with five lanes and six lanes, and a minor road with three lanes.In contrast, the unsignalized intersection has a main road with five lanes, which subsequently reduces to four lanes in the northbound direction, and a minor road with three lanes.The road geometries are generally similar, but the signalized intersection has a higher traffic volume.The signalized intersection was captured by a fixed camera within the recording range as indicated by the box outline in Figure 2. To facilitate a better and consistent comparison of the characteristics between signalized and unsignalized intersections, the internal area of the unsignalized intersection captured by a drone is also selected.The area does not include the road section leading to the intersection before entering it.
The file "DR_USA_Intersection_MA" consists of 22 Excel data sheets, with each sheet recording approximately 300,800 milliseconds, equivalent to 5 min.However, the file "TC_BGR_Intersection_VA" contains four Excel data sheets, each recording 899,900 milliseconds, which corresponds to 15 min.Each Excel data sheet primarily includes information such as track ID, vehicle types, vehicle sizes, current positions, current velocities, and orientations, as shown in Table 6.A partial data display is presented in Table 7.
At the VA intersection, a complete traffic light cycle lasts for 100 s, as shown in Figure 3.The table data are processed to retain complete traffic light cycles, with each table containing eight complete cycles, resulting in a total of 32 complete cycles, lasting for 3200 s.The traffic flow for each 800 s is 793, 858, 838, and 826 vehicles, respectively, totaling 3316 vehicles.On average, 103 vehicles pass through the intersection in each cycle of 100 s.To make a comparison with the unsignalized intersection while ensuring the animation length remains equal and traffic flow is as similar as possible, 300 s are selected from each table.The 11 tables with the highest traffic flow are chosen, and the final table is truncated to 200 s to match the duration of the VA intersection.For the MA intersection, the traffic flow for every 200 s is 181, 161, 155, 152, 147, 145, 142, 142, 141, and 141 vehicles.The last table with 200 s of traffic flow has 95 vehicles, resulting in a total of 1602 vehicles passing Energies 2023, 16, 7 of 24 through the unsignalized intersection over 3200 s.On average, 50 vehicles pass through the intersection in each 100 s.

No.
Field Meaning Explain

track_id
The ID of the agent.

frame_id
The frames when the agent appears in the video.

timestamp_ms
The time when the agent appears in the video.The unit is ms.

agent_type
The types of tracked agents.For example, it can be a car, a truck and so on.5 x The x position of the agent at each frame.
The unit is m.6 y The y position of the agent at each frame.
The unit is m.

v x
The velocity of the agent along x-direction at each frame.
The unit is m/s.8 v y The velocity of the agent along y-direction at each frame.
The unit is m/s.

Data Preprocessing
Zhan et al. [30] processed the collected video through three steps: video stabilization and alignment, detection, data association, and tracking and smoothing.The bounding boxes are very accurate, and the paths are smooth.The processed data are shown in Table 7.
The speed in the original table is v x and v y ; that is, the partial speed of the car along the x direction and the y direction.Equation ( 3) is used to calculate the instantaneous speed of the vehicle at a certain moment, and the unit is km/h.
Equation ( 4) is used to obtain the instantaneous acceleration of the vehicle at a certain moment and the unit is km/h/s.Outliers with accelerations greater than or less than 12.6 are discarded.
Equation ( 5) is used to obtain the total distance traveled by the vehicle at all recorded moments, and the unit is mm.

Analysis of Traffic Flow Characteristics at Signalized Intersection
By utilizing Python for data analysis and visualization, it was observed that vehicle movement at intersections can experience delays due to signal light restrictions, resulting in some temporal gaps.For instance, at 320,600 milliseconds, a vehicle with carID 1411 was positioned in the left-turn lane.There were no vehicles obstructing its left-turn path in the adjacent oncoming lanes or intersecting straight lanes, as illustrated in Figure 4a.However, data indicated that carID 1411 could only begin its left-turn maneuver at ts 335,200 milliseconds, as depicted in Figure 4b.During the approximately 14.6-s interval from 320,600 ms to 335,200 ms, carID 1411 and other vehicles waiting to make a left-turn had to remain stationary, waiting for the left-turn signal to turn green.This phenomenon illustrates that due to signal light restrictions, vehicles that could safely make left turns are unable to do so until the left-turn signal is green, resulting in a wasted time of about 15 s.A similar observation is demonstrated in Figure 5.At ts 359,000 milliseconds, carID 1478 had no other vehicles obstructing its left-turn path, yet it remained stationary until ts 390,700 milliseconds when it finally executed the left-turn maneuver, incurring a delay of 31.7 s.

Analysis of Traffic Flow Characteristics at Signalized Intersection
By utilizing Python for data analysis and visualization, it was observed that vehicle movement at intersections can experience delays due to signal light restrictions, resulting in some temporal gaps.For instance, at 320,600 milliseconds, a vehicle with carID 1411 was positioned in the left-turn lane.There were no vehicles obstructing its left-turn path in the adjacent oncoming lanes or intersecting straight lanes, as illustrated in Figure 4a.However, data indicated that carID 1411 could only begin its left-turn maneuver at ts 335,200 milliseconds, as depicted in Figure 4b.During the approximately 14.6-s interval from 320,600 ms to 335,200 ms, carID 1411 and other vehicles waiting to make a left-turn had to remain stationary, waiting for the left-turn signal to turn green.This phenomenon illustrates that due to signal light restrictions, vehicles that could safely make left turns are unable to do so until the left-turn signal is green, resulting in a wasted time of about 15 s.A similar observation is demonstrated in Figure 5.At ts 359,000 milliseconds, carID 1478 had no other vehicles obstructing its left-turn path, yet it remained stationary until ts 390,700 milliseconds when it finally executed the left-turn maneuver, incurring a delay of 31.7 s.As shown in Figure 6, at 55,400 milliseconds, there were no impediments for northboundto-southbound vehicles; however, they only began to pass through the intersection at 60,400 milliseconds, wasting 5 s of passage capacity.As shown in Figure 6, at 55,400 milliseconds, there were no impediments for northbound-to-southbound vehicles; however, they only began to pass through the intersection at 60,400 milliseconds, wasting 5 s of passage capacity.

Analysis of Traffic Flow Characteristics at Unsignalized Intersection
Using Python in conjunction with the 11 tables from the MA intersection, it is possible to visualize the traffic flow at the unsignalized intersection.Analyzing the traffic flow animation reveals that the unsignalized intersection experiences brief congestion.For example, as shown in Figure 7, at 11,500 milliseconds, Vehicle 25 starts queuing and waiting.At this moment, there is heavy traffic in all four directions.It continues to wait until 41,500 milliseconds before vehicles start moving into the intersection.This waiting time lasts for 30 s, and the brief congestion results in relatively longer waiting times compared to when signal lights are present.

Analysis of Traffic Flow Characteristics at Unsignalized Intersection
Using Python in conjunction with the 11 tables from the MA intersection, it is possible to visualize the traffic flow at the unsignalized intersection.Analyzing the traffic flow animation reveals that the unsignalized intersection experiences brief congestion.For example, as shown in Figure 7, at 11,500 milliseconds, Vehicle 25 starts queuing and waiting.At this moment, there is heavy traffic in all four directions.It continues to wait until 41,500 milliseconds before vehicles start moving into the intersection.This waiting time lasts for 30 s, and the brief congestion results in relatively longer waiting times compared to when signal lights are present.
imation reveals that the unsignalized intersection experiences brief congestion.For example, as shown in Figure 7, at 11,500 milliseconds, Vehicle 25 starts queuing and waiting.At this moment, there is heavy traffic in all four directions.It continues to wait until 41,500 milliseconds before vehicles start moving into the intersection.This waiting time lasts for 30 s, and the brief congestion results in relatively longer waiting times compared to when signal lights are present.The total NOx emissions for each 800 s at the signalized intersection are calculated to be 56,819.88g/100 km, 57,136.75g/100 km, 55,396.08g/100 km, and 58,384.32g/100 km, as shown in Figure 8.The average NOx emissions for each cycle of 100 s is 7116.78g/100 km, and the average NOx emissions per vehicle is 68.76 g/100 km.
The total CO2 emissions for each 800 s at the signalized intersection are calculated to be 48,322.76kg/100 km, 51,994.83kg/100 km, 50,647.47kg/100 km, and 51,475.77kg/100 km, as shown in Figure 8.The average CO2 emissions for each cycle of 100 s is 6326.28kg/100 km, and the average CO2 emissions per vehicle is 61.07 kg/100 km.Using the VA003 file as an example, the fuel consumption and emissions for each vehicle are shown in Figure 9. Vehicles passing through the signalized intersection generate varying levels of fuel consumption.Due to the restrictions imposed by the traffic signals, some vehicles can pass through the intersection without the need for speed changes, resulting in lower fuel consumption and emissions, as illustrated in Figure 10 for carID 3029.However, vehicles that require speed adjustments while passing through the intersection generate higher fuel consumption and emissions, as shown in Figure 10 for carID 2795.This diversity in how vehicles pass through the intersection leads to significant differences in fuel consumption when vehicles traverse the signalized intersection.The total NO x emissions for each 800 s at the signalized intersection are calculated to be 56,819.88g/100 km, 57,136.75g/100 km, 55,396.08g/100 km, and 58,384.32g/100 km, as shown in Figure 8.The average NO x emissions for each cycle of 100 s is 7116.78g/100 km, and the average NO x emissions per vehicle is 68.76 g/100 km.
The total CO 2 emissions for each 800 s at the signalized intersection are calculated to be 48,322.76kg/100 km, 51,994.83kg/100 km, 50,647.47kg/100 km, and 51,475.77kg/100 km, as shown in Figure 8.The average CO 2 emissions for each cycle of 100 s is 6326.28kg/100 km, and the average CO 2 emissions per vehicle is 61.07 kg/100 km.
Using the VA003 file as an example, the fuel consumption and emissions for each vehicle are shown in Figure 9. Vehicles passing through the signalized intersection generate varying levels of fuel consumption.Due to the restrictions imposed by the traffic signals, some vehicles can pass through the intersection without the need for speed changes, resulting in lower fuel consumption and emissions, as illustrated in Figure 10 for carID 3029.However, vehicles that require speed adjustments while passing through the intersection generate higher fuel consumption and emissions, as shown in Figure 10 for carID 2795.This diversity in how vehicles pass through the intersection leads to significant differences in fuel consumption when vehicles traverse the signalized intersection.
ate varying levels of fuel consumption.Due to the restrictions imposed by the traffic signals, some vehicles can pass through the intersection without the need for speed changes, resulting in lower fuel consumption and emissions, as illustrated in Figure 10 for carID 3029.However, vehicles that require speed adjustments while passing through the intersection generate higher fuel consumption and emissions, as shown in Figure 10 for carID 2795.This diversity in how vehicles pass through the intersection leads to significant differences in fuel consumption when vehicles traverse the signalized intersection.When a large number of vehicles gather at a signalized intersection, it can lead to road congestion, as illustrated in Figure 11.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at a signalized intersection, fuel consumption rapidly increases.When a large number of vehicles gather at a signalized intersection, it can lead to road congestion, as illustrated in Figure 11.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at a signalized intersection, fuel consumption rapidly increases.When a large number of vehicles gather at a signalized intersection, it can lead to road congestion, as illustrated in Figure 11.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at a signalized intersection, fuel consumption rapidly increases.The total CO2 emissions for each 300 s at the unsignalized intersection are calculated to be 16,329.96kg/100 km, 20,114.82kg/100 km, 18,476.88kg/100 km, 15,909.17kg/100 km, 14,401.01kg/100 km, 14,560.62kg/100 km, 15,380.11kg/100 km, 14,726.63kg/100 km, 15,734.95kg/100 km, 16,771.25 kg/100 km, and 9418.75 kg/100 km (for the 200 s interval), as shown in Figure 12.The average CO2 emissions for each cycle of 100 s is 5349.50kg/100 km, and the average CO2 emissions per vehicle is 107.16 kg/100 km.
Using the MA20 file as an example, the fuel consumption and emissions for each vehicle are depicted in Figure 13.Vehicles passing through the unsignalized intersection exhibit relatively small variations in fuel consumption.Without the restrictions imposed by traffic signals, there are fewer instances where vehicles experience significant fuel consumption due to prolonged stops.Instead, most vehicles either accelerate directly through the intersection, as seen in Figure 14 for carID 56, or decelerate and pass through after other vehicles, as illustrated in Figure 14 for carID 60 and carID 66.As a result, the fuel consumption generated by vehicles passing through the unsignalized intersection appears to be quite similar.The total CO 2 emissions for each 300 s at the unsignalized intersection are calculated to be 16,329.96kg/100 km, 20,114.82kg/100 km, 18,476.88kg/100 km, 15,909.17kg/100 km, 14,401.01kg/100 km, 14,560.62kg/100 km, 15,380.11kg/100 km, 14,726.63kg/100 km, 15,734.95kg/100 km, 16,771.25 kg/100 km, and 9418.75 kg/100 km (for the 200 s interval), as shown in Figure 12.The average CO 2 emissions for each cycle of 100 s is 5349.50kg/100 km, and the average CO 2 emissions per vehicle is 107.16 kg/100 km.
Using the MA20 file as an example, the fuel consumption and emissions for each vehicle are depicted in Figure 13.Vehicles passing through the unsignalized intersection exhibit relatively small variations in fuel consumption.Without the restrictions imposed by traffic signals, there are fewer instances where vehicles experience significant fuel consumption due to prolonged stops.Instead, most vehicles either accelerate directly through the intersection, as seen in Figure 14 for carID 56, or decelerate and pass through after other vehicles, as illustrated in Figure 14 for carID 60 and carID 66.As a result, the fuel consumption generated by vehicles passing through the unsignalized intersection appears to be quite similar.
exhibit relatively small variations in fuel consumption.Without the restrictions imposed by traffic signals, there are fewer instances where vehicles experience significant fuel consumption due to prolonged stops.Instead, most vehicles either accelerate directly through the intersection, as seen in Figure 14 for carID 56, or decelerate and pass through after other vehicles, as illustrated in Figure 14 for carID 60 and carID 66.As a result, the fuel consumption generated by vehicles passing through the unsignalized intersection appears to be quite similar.When vehicles pass through an unsignalized intersection, they encounter more instances of rapid speed changes.Without signal guidance, vehicles rely more on the drivers' own driving behavior when traversing the intersection.When vehicles meet at the intersection, one may accelerate through, while the other urgently brakes and slows down.These abrupt speed changes result in higher fuel consumption, leading to a higher average fuel consumption for vehicles passing through unsignalized intersections compared to signalized ones.As shown in Figure 15, when carID 56 encounters carID 62, carID 56 accelerates through the intersection, while carID 62 urgently decelerates and waits for carID 56 to pass through the intersection before accelerating again.
When a large number of vehicles gather at an unsignalized intersection, it can lead to road congestion, as shown in Figure 16.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at an unsignalized intersection, fuel consumption rapidly increases.When vehicles pass through an unsignalized intersection, they encounter more instances of rapid speed changes.Without signal guidance, vehicles rely more on the drivers' own driving behavior when traversing the intersection.When vehicles meet at the intersection, one may accelerate through, while the other urgently brakes and slows down.These abrupt speed changes result in higher fuel consumption, leading to a higher average fuel consumption for vehicles passing through unsignalized intersections compared to signalized ones.As shown in Figure 15, when carID 56 encounters carID 62, carID 56 accelerates through the intersection, while carID 62 urgently decelerates and waits for carID 56 to pass through the intersection before accelerating again.When vehicles pass through an unsignalized intersection, they encounter more instances of rapid speed changes.Without signal guidance, vehicles rely more on the drivers' own driving behavior when traversing the intersection.When vehicles meet at the intersection, one may accelerate through, while the other urgently brakes and slows down.These abrupt speed changes result in higher fuel consumption, leading to a higher average fuel consumption for vehicles passing through unsignalized intersections compared to signalized ones.As shown in Figure 15, when carID 56 encounters carID 62, carID 56 accelerates through the intersection, while carID 62 urgently decelerates and waits for carID 56 to pass through the intersection before accelerating again.
When a large number of vehicles gather at an unsignalized intersection, it can lead to road congestion, as shown in Figure 16.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at an unsignalized intersection, fuel consumption rapidly increases.When a large number of vehicles gather at an unsignalized intersection, it can lead to road congestion, as shown in Figure 16.Road congestion inevitably causes vehicles to experience abrupt accelerations and decelerations, resulting in the highest fuel consumption.Therefore, when congestion occurs at an unsignalized intersection, fuel consumption rapidly increases.

Comparison Analysis between Signalized and Unsignalized Intersections
Based on Figure 8 and Figure 12, along with Equations ( 1) and ( 2), it is evident that vehicle fuel consumption, NOx emissions, and CO2 emissions are all influenced by the amount of traffic flow.The total fuel consumption, NOx emissions, and CO2 emissions for vehicles at signalized and unsignalized intersections, along with the averages per cycle of 100 s and per vehicle, are shown in Figure 17.At signalized intersections, the traffic flow is larger than at unsignalized intersections,

Comparison Analysis between Signalized and Unsignalized Intersections
Based on Figures 8 and 12, along with Equations ( 1) and ( 2), it is evident that vehicle fuel consumption, NO x emissions, and CO 2 emissions are all influenced by the amount of traffic flow.The total fuel consumption, NO x emissions, and CO 2 emissions for vehicles at signalized and unsignalized intersections, along with the averages per cycle of 100 s and per vehicle, are shown in Figure 17.

Comparison Analysis between Signalized and Unsignalized Intersections
Based on Figure 8 and Figure 12, along with Equations ( 1) and ( 2), it is evident that vehicle fuel consumption, NOx emissions, and CO2 emissions are all influenced by the amount of traffic flow.The total fuel consumption, NOx emissions, and CO2 emissions for vehicles at signalized and unsignalized intersections, along with the averages per cycle of 100 s and per vehicle, are shown in Figure 17.At signalized intersections, the traffic flow is larger than at unsignalized intersections, sometimes even twice as much.The average traffic flow within one cycle of 100 s is also twice as much at signalized intersections compared to unsignalized ones.However, At signalized intersections, the traffic flow is larger than at unsignalized intersections, sometimes even twice as much.The average traffic flow within one cycle of 100 s is also twice as much at signalized intersections compared to unsignalized ones.However, surprisingly, the average NO x emissions within one cycle at unsignalized intersections even exceed those at signalized intersections.Additionally, the average fuel consumption, NO x emissions, and CO 2 emissions per vehicle are higher at unsignalized intersections compared to signalized ones.Consequently, it can be concluded that unsignalized intersections have lower traffic capacity, higher fuel consumption, and higher emissions compared to signalized intersections.Signalized intersections not only ensure safety but also save energy and produce lower emissions compared to unsignalized ones.

Comparative Analysis of One Cycle Operation Characteristics and Fuel Consumption between Signalized and Unsignalized Intersections
One traffic signal cycle (100 s) at the VA intersection was selected.There were 108 vehicles passing through, including 66 vehicles driving straight, 18 vehicles making left turns, 21 vehicles making right turns, and three vehicles making U-turns.At the MA intersection, within 100 s, there were 61 vehicles passing through, including 37 vehicles driving straight, 20 vehicles making left turns, four vehicles making right turns, and zero vehicles making U-turns.
At the VA intersection, during one traffic signal cycle, the average speed of 66 vehicles driving straight is 33.74 km/h, with an average fuel consumption of 22.35 L/100 km, NO x emissions of 77.21 g/100 km, and CO 2 emissions of 50.93 kg/100 km.The average speed of 18 vehicles making left turns is 16.75 km/h, with an average fuel consumption of 42.33 L/100 km, NO x emissions of 66.14 g/100 km, and CO 2 emissions of 98.44 kg/100 km.The average speed of 21 vehicles making right turns is 13.85 km/h, with an average fuel consumption of 23.13 L/100 km, NO x emissions of 33.75 g/100 km, and CO 2 emissions of 53.96 kg/100 km.The average speed of 3 vehicles making U-turns is 2.34 km/h, with an average fuel consumption of 114.38 L/100 km, NO x emissions of 140.02 g/100 km, and CO 2 emissions of 265.46 kg/100 km.
At the MA intersection, during one traffic signal cycle, the average speed of 37 vehicles driving straight is 12.86 km/h, with an average fuel consumption of 47.39 L/100 km, NO x emissions of 153.97 g/100 km, and CO 2 emissions of 107.48 kg/100 km.The average speed of 20 vehicles making left turns is 12.25 km/h, with an average fuel consumption of 44.91 L/100 km, NO x emissions of 131.34 g/100 km, and CO 2 emissions of 102.95 kg/100 km.The average speed of four vehicles making right turns is 10.89 km/h, with an average fuel consumption of 43.55 L/100 km, NO x emissions of 103.98 g/100 km, and CO 2 emissions of 102.41 kg/100 km.

Analysis of Operation Characteristics at Signalized and Unsignalized Intersections
The average velocity of driving straight, turning left, turning right, and turning around in a period of signalized and unsignalized intersection is shown in Figure 18.As shown in Figure 18, at signalized intersections, the average speed of vehicles driving straight is the highest, followed by vehicles making left turns.The speeds of vehicles making right turns and U-turns are relatively similar, but the U-turn speed is very low.When the green light for driving straight is on, there is usually no safety hazard, so vehicles accelerate through the intersection, resulting in the highest speed.For left turns, vehicles need to enter the waiting area before accelerating through the intersection, while right turns are not restricted by traffic lights, but they must yield to pedestrians, leading to relatively lower speeds.U-turning vehicles typically need to yield to vehicles driving straight and may have conflicts with vehicles making right turns at large turning radii, resulting in a stop-and-go situation and, therefore, lower average speeds.However, at unsignalized intersections, the speeds of vehicles driving straight, making left turns, and making right turns are similar.Without the restriction of traffic lights, these vehicles usually proceed while observing and waiting for no oncoming traffic before quickly passing through the intersection, following the "first come, first served" rule and yielding to vehicles making turns, which results in similar speeds among these vehicles.

Analysis of Operation Characteristics at Signalized Intersection
At signalized intersections, the speed of 66 vehicles driving straight through the intersection is shown in Figure 19.On average, it takes 5.12 s for vehicles to pass through the intersection.Most vehicles accelerate through the intersection, with a few even reaching speeds exceeding 50 km/h, as shown in Figure 20.In this case, the green light is about to end, and carID 551 only takes 2.6 s to pass through the intersection.There are also some vehicles that decelerate to almost zero speed before accelerating through the intersection.This is because they encountered U-turning vehicles ahead, causing a brief congestion, and they had to reduce their speed and wait, as shown in Figure 21.The average vehicle speed is 33.74 km/h.

Analysis of Operation Characteristics at Signalized Intersection
At signalized intersections, the speed of 66 vehicles driving straight through the intersection is shown in Figure 19.On average, it takes 5.12 s for vehicles to pass through the intersection.Most vehicles accelerate through the intersection, with a few even reaching speeds exceeding 50 km/h, as shown in Figure 20.In this case, the green light is about to end, and carID 551 only takes 2.6 s to pass through the intersection.There are also some vehicles that decelerate to almost zero speed before accelerating through the intersection.This is because they encountered U-turning vehicles ahead, causing a brief congestion, and they had to reduce their speed and wait, as shown in Figure 21.The average vehicle speed is 33.74 km/h.At the signalized intersection, the speed of 18 vehicles making left turns through the intersection is shown in Figure 22.On average, it takes 13.4 s for vehicles to make a left turn through the intersection.Most vehicles slow down as they enter the intersection and then accelerate to pass through it.For left turns from the main road, there is a waiting area, so vehicles must come to a stop and wait until there are no oncoming vehicles before proceeding, as shown in Figure 23.For example, carID163 had to wait for 40 s before making the left turn.However, left turns from the minor road directly proceed when the leftturn signal is green, resulting in acceleration through the intersection.The average vehicle speed for left turns is 16.75 km/h.At the signalized intersection, the speed of 18 vehicles making left turns through the intersection is shown in Figure 22.On average, it takes 13.4 s for vehicles to make a left turn through the intersection.Most vehicles slow down as they enter the intersection and then accelerate to pass through it.For left turns from the main road, there is a waiting area, so vehicles must come to a stop and wait until there are no oncoming vehicles before proceeding, as shown in Figure 23.For example, carID163 had to wait for 40 s before making the left turn.However, left turns from the minor road directly proceed when the left-turn signal is green, resulting in acceleration through the intersection.The average vehicle speed for left turns is 16.75 km/h.At the signalized intersection, the speed of 18 vehicles making left turns through the intersection is shown in Figure 22.On average, it takes 13.4 s for vehicles to make a left turn through the intersection.Most vehicles slow down as they enter the intersection and then accelerate to pass through it.For left turns from the main road, there is a waiting area, so vehicles must come to a stop and wait until there are no oncoming vehicles before proceeding, as shown in Figure 23.For example, carID163 had to wait for 40 s before making the left turn.However, left turns from the minor road directly proceed when the leftturn signal is green, resulting in acceleration through the intersection.The average vehicle speed for left turns is 16.75 km/h.At the signalized intersection, the speed of 21 vehicles making right turns thro the intersection is shown in Figure 24.At the signalized intersection, the speed of 21 vehicles making right turns through the intersection is shown in Figure 24.The average speeds for driving straight, making left turns, and making right turns are similar, and the time needed is also similar.The trend for all three movements is to slow down upon entering the intersection and then accelerate to pass through it.The average speeds for driving straight, making left turns, and making right turns are similar, and the time needed is also similar.The trend for all three movements is to slow down upon entering the intersection and then accelerate to pass through it.The average speeds for driving straight, making left turns, and making right turns are similar, and the time needed is also similar.The trend for all three movements is to slow down upon entering the intersection and then accelerate to pass through it.

Analysis of Fuel Consumption and Emission Characteristics at Signalized and Unsignalized Intersections
Using left turns and right turns at the signalized intersection as examples, the average speed, total fuel consumption, and total emission values for each vehicle are shown in Figures 28 and 29.Combining the analysis from the previous speed graphs (Figures 22 and 24), it can be observed that vehicles with slower speeds have higher fuel consumption and emissions.Vehicles with similar driving conditions generally exhibit similar fuel consumption and emission levels.

Analysis of Fuel Consumption and Emission Characteristics at Signalized and Unsignalized Intersections
Using left turns and right turns at the signalized intersection as examples, the average speed, total fuel consumption, and total emission values for each vehicle are shown in Figures 28 and 29.Combining the analysis from the previous speed graphs (Figures 22  and 24), it can be observed that vehicles with slower speeds have higher fuel consumption and emissions.Vehicles with similar driving conditions generally exhibit similar fuel consumption and emission levels.Using straight-through and left turns at the unsignalized intersection as examples, the average speed, total fuel consumption, and total emission values for each vehicle within a 100 s cycle are shown in Figures 30 and 31.Vehicles with similar driving conditions generally exhibit similar fuel consumption and emission levels.However, carID22 and carID29 show significantly higher NOx emissions due to their higher acceleration rates.Using straight-through and left turns at the unsignalized intersection as examples, the average speed, total fuel consumption, and total emission values for each vehicle within a 100 s cycle are shown in Figures 30 and 31.Vehicles with similar driving conditions generally exhibit similar fuel consumption and emission levels.However, carID22 and carID29 show significantly higher NO x emissions due to their higher acceleration rates.

Comparison Analysis between Signalized and Unsignalized Intersections
The average speed, average fuel consumption, and emission levels of vehicles within a single cycle at signalized and unsignalized intersections are shown in Figure 32.The highest fuel consumption and CO2 emissions occur during U-turns.At signalized intersections, left turns have the highest fuel consumption and CO2 emissions, while right turns and straight-through movements are similar in this regard.However, for NOx emissions,

Comparison Analysis between Signalized and Unsignalized Intersections
The average speed, average fuel consumption, and emission levels of vehicles within a single cycle at signalized and unsignalized intersections are shown in Figure 32.The highest fuel consumption and CO2 emissions occur during U-turns.At signalized intersections, left turns have the highest fuel consumption and CO2 emissions, while right turns and straight-through movements are similar in this regard.However, for NOx emissions,

Comparison Analysis between Signalized and Unsignalized Intersections
The average speed, average fuel consumption, and emission levels of vehicles within a single cycle at signalized and unsignalized intersections are shown in Figure 32.The highest fuel consumption and CO 2 emissions occur during U-turns.At signalized intersections, left turns have the highest fuel consumption and CO 2 emissions, while right turns and straight-through movements are similar in this regard.However, for NO x emissions, straight-through movements have the highest levels compared to left and right turns.At unsignalized intersections, the fuel consumption and emissions are generally similar across all movement types.In terms of NO x emissions, straight-through movements have the highest levels compared to left and right turns, possibly due to their longer travel time.It is inferred that the higher emissions during left turns at signalized intersections are caused by the secondary deceleration and stop required in the left-turn waiting zone before accelerating again, leading to increased emissions.Comparing vehicles at signalized and unsignalized intersections within one cycle, regardless of whether they are driving straight, turning left, or turning right, signalized intersections have lower fuel consumption and emissions than unsignalized intersections.Additionally, vehicles spend less time passing through signalized intersections; this type of intersection provides a higher level of safety assurance.Therefore, within the scope of this study, when the average traffic volume ranges from 50 to 103 vehicles in a 100-s cycle, signalized intersections perform better in terms of fuel consumption and emissions compared to unsignalized intersections.

Conclusions
In the INTERACTION dataset, two signalized (VA) and unsignalized (MA) intersections with similar road shapes were selected to study vehicle operation characteristics, fuel consumption, and emissions characteristics.In the signalized intersection, a total of 3316 vehicles passed through during the captured 3200 s.In the unsignalized intersection, a total of 1602 vehicles passed through during the captured 3200 s.The transportation capacity at the signalized intersection is much greater than that at the unsignalized intersection.
At the signalized intersection, the total fuel consumption was 87,968.68L/100 km, the total NOx emissions were 227,737.03g/100 km, and the total CO2 emissions were 202,440.82kg/100 km.At the unsignalized intersection, during the same period, the total fuel consumption was 75,205.00L/100 km, the total NOx emissions were 239,205.59g/100 km, and the total CO2 emissions were 171,824.15kg/100 km.When the traffic flow at the unsignalized intersection is half that of the signalized intersection, the total NOx emissions at the unsignalized intersection even exceed that of the signalized intersection.In more detail, at the signalized intersection, the average fuel consumption per vehicle was 26.54 L/100 km, with an NOx emission of 68.76 g/100 km and a CO2 emission of 61.07 g/100 km.Conversely, at the unsignalized intersection, the average fuel consumption per vehicle was 46.88 L/100 km, with an NOx emission of 149.26 g/100 km and a CO2 emission of 107.16   Comparing vehicles at signalized and unsignalized intersections within one cycle, regardless of whether they are driving straight, turning left, or turning right, signalized intersections have lower fuel consumption and emissions than unsignalized intersections.Additionally, vehicles spend less time passing through signalized intersections; this type of intersection provides a higher level of safety assurance.Therefore, within the scope of this study, when the average traffic volume ranges from 50 to 103 vehicles in a 100-s cycle, signalized intersections perform better in terms of fuel consumption and emissions compared to unsignalized intersections.

Conclusions
In the INTERACTION dataset, two signalized (VA) and unsignalized (MA) intersections with similar road shapes were selected to study vehicle operation characteristics, fuel consumption, and emissions characteristics.In the signalized intersection, a total of 3316 vehicles passed through during the captured 3200 s.In the unsignalized intersection, a total of 1602 vehicles passed through during the captured 3200 s.The transportation capacity at the signalized intersection is much greater than that at the unsignalized intersection.
At the signalized intersection, the total fuel consumption was 87,968.68L/100 km, the total NO x emissions were 227,737.03g/100 km, and the total CO 2 emissions were 202,440.82kg/100 km.At the unsignalized intersection, during the same period, the total fuel consumption was 75,205.00L/100 km, the total NO x emissions were 239,205.59g/100 km, and the total CO 2 emissions were 171,824.15kg/100 km.When the traffic flow at the unsignalized intersection is half that of the signalized intersection, the total NO x emissions at the unsignalized intersection even exceed that of the signalized intersection.In more detail, at the signalized intersection, the average fuel consumption per vehicle was 26.54 L/100 km, with an NO x emission of 68.76 g/100 km and a CO 2 emission of 61.07 g/100 km.Conversely, at the unsignalized intersection, the average fuel consump-tion per vehicle was 46.88 L/100 km, with an NO x emission of 149.26 g/100 km and a CO 2 emission of 107.16 g/100 km.The average fuel consumption, NO x emissions, and CO 2 emissions per vehicle at the unsignalized intersection are all higher than at the signalized intersection.This leads to the conclusion that the capacity, fuel consumption, and emissions at the unsignalized intersection are inferior to those at the signalized intersection.The signalized intersection ensures both safety and energy conservation while also having lower emissions compared to the unsignalized intersection.
One traffic-signal cycle (100 s) at the VA intersection and the same 100 s at the MA intersection are selected to study.There were 108 vehicles passing through at the VA intersection, and there were 61 vehicles passing through at the MA intersection within 100 s.Comparing vehicles at signalized and unsignalized intersections within one cycle, regardless of whether they are driving straight, turning left, or turning right, at signalized intersections have lower fuel consumption and emissions than at unsignalized intersections.Additionally, vehicles spend less time passing through signalized intersections, suggesting that signalized intersections not only improve road traffic efficiency but also reduce energy consumption and emissions.Therefore, within the scope of this study, when the average traffic volume ranges from 50 to 103 vehicles in a 100-s cycle, signalized intersections outperform unsignalized intersections in terms of transportation capacity, energy consumption, and emissions.
In our subsequent research, we aspire to conduct experiments for data collection and utilize algorithms to process and obtain vehicle speed and position information.We intend to explore the potential errors that may arise during the application of various algorithms, including computer vision, optical-flow estimation, object tracking, object detection, deep learning, vehicle calibration, sensor fusion, and Kalman filtering.Our goal is to analyze the impact of these errors and their cumulative effects on the final results.

Figure 1 .
Figure 1.A diagram of the methodology of this paper.

Figure 1 .
Figure 1.A diagram of the methodology of this paper.

Figure 3 .
Figure 3. Signal light-change diagram for the VA intersection.2.2.2.Data PreprocessingZhan et al.[30] processed the collected video through three steps: video stabilization and alignment, detection, data association, and tracking and smoothing.The bounding

Figure 3 .
Figure 3. Signal light-change diagram for the VA intersection.

Figure 4 .
Figure 4.The timestamp of carID 1411 at the VA intersection.Each blue dot represents each agent.The bounding box is the border of the agent and represents the length and width of the agent.Same in the figures below.(a) The safe passage time for carID 1411.(b) The actual passage time for carID 1411.

Figure 4 .
Figure 4.The timestamp of carID 1411 at the VA intersection.Each blue dot represents each agent.The bounding box is the border of the agent and represents the length and width of the agent.Same in the figures below.(a) The safe passage time for carID 1411.(b) The actual passage time for carID 1411.

Figure 4 .Figure 5 .
Figure 4.The timestamp of carID 1411 at the VA intersection.Each blue dot represents each age The bounding box is the border of the agent and represents the length and width of the agent.Sam in the figures below.(a) The safe passage time for carID 1411.(b) The actual passage time for car 1411.

Figure 5 .
Figure 5.The timestamp of carID 1478 at the VA intersection.(a) The safe passage time for carID 1478.(b) The actual passage time for carID 1478.

Figure 6 .
Figure 6.The timestamp of carID 323 at the VA intersection.(a) The safe passage time for carID 323.(b) The actual passage time for carID 323.

Figure 6 .
Figure 6.The timestamp of carID 323 at the VA intersection.(a) The safe passage time for carID 323.(b) The actual passage time for carID 323.

Figure 7 .
Figure 7.The timestamp of carID 25 at the MA intersection.(a) The start waiting time for carID 25.(b) The actual passage time for carID 25.

Figure 7 .
Figure 7.The timestamp of carID 25 at the MA intersection.(a) The start waiting time for carID 25.(b) The actual passage time for carID 25.

3. 2 .
Analysis of Energy and Consumption Characteristics 3.2.1.Analysis of Energy and Consumption Characteristics at Signalized Intersection Using the VT-Micro energy and emission model Equations (1) and (2), the total fuel consumption for the four files at the signalized intersection is calculated to be 21,012.19L/100 km, 22,594.39L/100 km, 22,001.61L/100 km, and 22,360.49L/100 km, as shown in Figure 8.The average fuel consumption for each cycle of 100 s is 2749.02L/100 km, and the average fuel consumption per vehicle is 26.54 L/100 km.Energies 2023, 16, x FOR PEER REVIEW 11 of 26 3.2.Analysis of Energy and Consumption Characteristics 3.2.1.Analysis of Energy and Consumption Characteristics at Signalized Intersection Using the VT-Micro energy and emission model Equations (1) and (2), the total fuel consumption for the four files at the signalized intersection is calculated to be 21,012.19L/100 km, 22,594.39L/100 km, 22,001.61L/100 km, and 22,360.49L/100 km, as shown in Figure 8.The average fuel consumption for each cycle of 100 s is 2749.02L/100 km, and the average fuel consumption per vehicle is 26.54 L/100 km.

Figure 8 .
Figure 8.Total vehicle flow, fuel consumption, and emissions per VA file (per 800 s).

Figure 8 .
Figure 8.Total vehicle flow, fuel consumption, and emissions per VA file (per 800 s).

Figure 9 .
Figure 9. Energy consumption and emissions per vehicle in VA003 file.Figure 9. Energy consumption and emissions per vehicle in VA003 file.

Figure 9 . 26 Figure 10 .
Figure 9. Energy consumption and emissions per vehicle in VA003 file.Figure 9. Energy consumption and emissions per vehicle in VA003 file.Energies 2023, 16, x FOR PEER REVIEW 12 of 26

Figure 11 .
Figure 11.Congestion at signalized intersections.3.2.2.Analysis of Energy and Consumption Characteristics at Unsignalized Intersection Using the VT-Micro energy and emission model Formulas 1 and 2, the total fuel con-

Figure 11 .Figure 11 .
Figure 11.Congestion at signalized intersections.3.2.2.Analysis of Energy and Consumption Characteristics at Unsignalized Intersection Using the VT-Micro energy and emission model Formulas 1 and 2, the total fuel consumption for the 11 files at the unsignalized intersection is calculated to be 7182.28L/100

3. 2 . 2 . 26 Figure 12 .
Figure 12.The average NOx emissions for each cycle of 100 s is 7443.48g/100 km, and the average NOx emissions per vehicle is 149.26 g/100 km.

Figure 12 .
Figure 12.Total vehicle flow, fuel consumption, and emissions per MA file (per 300 s and MA20 is 200 s).

Figure 13 .
Figure 13.Energy consumption and emissions per vehicle in MA20 file.

Figure 12 .
Figure 12.Total vehicle flow, fuel consumption, and emissions per MA file (per 300 s and MA20 is 200 s).The total NO x emissions for each 300 s at the unsignalized intersection are calculated to be 23,913.26g/100 km, 26,522.91g/100 km, 25,807.78g/100 km, 22,916.62g/100 km, 20,033.96g/100 km, 21,032.22g/100 km, 21,262.30g/100 km, 21,135.09g/100 km, 20,398.04g/100 km, 23,325.24g/100 km, and 12,858.19g/100 km (for the 200 s interval), as shown in Figure 12.The average NO x emissions for each cycle of 100 s is 7443.48g/100 km, and the average NO x emissions per vehicle is 149.26 g/100 km.The total CO 2 emissions for each 300 s at the unsignalized intersection are calculated to be 16,329.96kg/100 km, 20,114.82kg/100 km, 18,476.88kg/100 km, 15,909.17kg/100 km, 14,401.01kg/100 km, 14,560.62kg/100 km, 15,380.11kg/100 km, 14,726.63kg/100 km, 15,734.95kg/100 km, 16,771.25 kg/100 km, and 9418.75 kg/100 km (for the 200 s interval), as shown in Figure 12.The average CO 2 emissions for each cycle of 100 s is 5349.50kg/100 km, and the average CO 2 emissions per vehicle is 107.16 kg/100 km.Using the MA20 file as an example, the fuel consumption and emissions for each vehicle are depicted in Figure13.Vehicles passing through the unsignalized intersection exhibit relatively small variations in fuel consumption.Without the restrictions imposed by traffic signals, there are fewer instances where vehicles experience significant fuel consumption due to prolonged stops.Instead, most vehicles either accelerate directly through the intersection, as seen in Figure14for carID 56, or decelerate and pass through after other vehicles, as illustrated in Figure14for carID 60 and carID 66.As a result, the fuel consumption generated by vehicles passing through the unsignalized intersection appears to be quite similar.

Figure 13 .
Figure 13.Energy consumption and emissions per vehicle in MA20 file.

Figure 15 .
Figure 15.Signal light-change diagram for the VA intersection.

Figure 15 .
Figure 15.Signal light-change diagram for the VA intersection.Figure 15.Signal light-change diagram for the VA intersection.

Figure 15 .
Figure 15.Signal light-change diagram for the VA intersection.Figure 15.Signal light-change diagram for the VA intersection.

Figure 17 .
Figure 17.The fuel consumption, NOx emissions, and CO2 emissions for vehicles at signalized and unsignalized intersections.(a) The total sum.(b) The average per cycle of 100 s.(c) The average per vehicle.

Figure 17 .
Figure 17.The fuel consumption, NOx emissions, and CO2 emissions for vehicles at signalized and unsignalized intersections.(a) The total sum.(b) The average per cycle of 100 s.(c) The average per vehicle.

Figure 17 .
Figure 17.The fuel consumption, NO x emissions, and CO 2 emissions for vehicles at signalized and unsignalized intersections.(a) The total sum.(b) The average per cycle of 100 s.(c) The average per vehicle.

Energies 2023 , 26 Figure 18 .Figure 18 .
Figure 18.The average velocity at signalized and unsignalized intersections.4.1.1.Analysis of Operation Characteristics at Signalized IntersectionAt signalized intersections, the speed of 66 vehicles driving straight through the intersection is shown in Figure19.On average, it takes 5.12 s for vehicles to pass through the intersection.Most vehicles accelerate through the intersection, with a few even reach-

Figure 18 .
Figure 18.The average velocity at signalized and unsignalized intersections.

Figure 20 .
Figure 20.The timestamp of carID 551 at the VA intersection.(a) The start time for carID 551.(b) The end time for carID 551.

Figure 20 .
Figure 20.The timestamp of carID 551 at the VA intersection.(a) The start time for carID 551.(b) The end time for carID 551.

Figure 21 .
Figure 21.The scenario where vehicles driving straight encounter U-turning vehicles in front of them.

Figure 22 .
Figure 22.The velocity-time plot of 18 cars turning left.

Figure 21 .
Figure 21.The scenario where vehicles driving straight encounter U-turning vehicles in front of them.

Figure 20 .
Figure 20.The timestamp of carID 551 at the VA intersection.(a) The start time for carID 551.(b) The end time for carID 551.

Figure 21 .
Figure 21.The scenario where vehicles driving straight encounter U-turning vehicles in front of them.

Figure 22 .
Figure 22.The velocity-time plot of 18 cars turning left.Figure 22.The velocity-time plot of 18 cars turning left.

Figure 22 .Figure 23 .
Figure 22.The velocity-time plot of 18 cars turning left.Figure 22.The velocity-time plot of 18 cars turning left.

Figure 23 .
Figure 23.The timestamp of carID 163 at the VA intersection.(a) The start waiting time for carID 163.(b) The start crossing time for carID 163.

Figure 23 .
Figure 23.The timestamp of carID 163 at the VA intersection.(a) The start waiting time for carID 163.(b) The start crossing time for carID 163.

Figure 24 .
Figure 24.The velocity-time plot of 21 cars turning right.

Figure 24 .
Figure 24.The velocity-time plot of 21 cars turning right.On average, it takes 4.82 s for vehicles to make a right turn through the intersection.Most vehicles slow down as they enter the intersection and then accelerate to pass through it.Right turns usually involve conflicts with pedestrians, and the right-turn signal is typically steady green.When encountering pedestrians, vehicles slow down and wait until the pedestrians have crossed before accelerating through the intersection.The average vehicle speed for right turns is 13.85 km/h.Out of the 21 vehicles making right turns, only carID 362 had a speed exceeding 25 km/h.4.1.2.Analysis of Operation Characteristics at Unsignalized Intersection At the unsignalized intersection, the average time needed to pass through the intersection is 16.84 s for driving straight, 15.36 s for making left turns, and 14.27 s for making right turns.The speeds of vehicles passing through the intersection for driving straight, making left turns, and making right turns are shown in Figures 25-27, respectively.Energies 2023, 16, x FOR PEER REVIEW 20 of 26

Figure 25 .
Figure 25.The velocity-time plot of 37 cars going straight at MA intersection.

Figure 25 .
Figure 25.The velocity-time plot of 37 cars going straight at MA intersection.

Figure 25 .
Figure 25.The velocity-time plot of 37 cars going straight at MA intersection.

Figure 26 .
Figure 26.The velocity-time plot of 20 cars turning left.

Figure 27 .
Figure 27.The velocity-time plot of 4 cars turning right.

Figure 26 .
Figure 26.The velocity-time plot of 20 cars turning left.

Figure 25 .
Figure 25.The velocity-time plot of 37 cars going straight at MA intersection.

Figure 26 .
Figure 26.The velocity-time plot of 20 cars turning left.

Figure 27 .
Figure 27.The velocity-time plot of 4 cars turning right.

Figure 27 .
Figure 27.The velocity-time plot of 4 cars turning right.

Figure 28 .
Figure 28.The fuel consumption and emission plot of 18 cars turning left at signalized intersection.

Figure 28 . 24 Figure 28 .
Figure 28.The fuel consumption and emission plot of 18 cars turning left at signalized intersection.

Figure 29 .
Figure 29.The fuel consumption and emission plot of 18 cars turning right at signalized intersection.

Figure 29 .
Figure 29.The fuel consumption and emission plot of 18 cars turning right at signalized intersection.

26 Figure 30 .
Figure 30.The fuel consumption and emission plot of 37 cars driving straight at unsignalized intersection.

Figure 31 .
Figure 31.The fuel consumption and emission plot of 20 cars turning left at unsignalized intersection.

Figure 30 .
Figure 30.The fuel consumption and emission plot of 37 cars driving straight at unsignalized intersection.

Figure 31 .
Figure 31.The fuel consumption and emission plot of 20 cars turning left at unsignalized intersection.

Figure 31 .
Figure 31.The fuel consumption and emission plot of 20 cars turning left at unsignalized intersection.

Energies 2023 , 26 Figure 32 .
Figure 32.The velocity, fuel consumption, and emission plot of one cycle at signalized and unsignalized intersection.

Figure 32 .
Figure 32.The velocity, fuel consumption, and emission plot of one cycle at signalized and unsignalized intersection.

Table 1 .
Previous research and research gaps.

Table 2 .
Correlation coefficient of fuel consumption MOE e (The unit is L/s).

Table 3 .
Correlation coefficient of NO x emission MOE e (The unit is mg/s).

Table 6 .
Field names and meanings of dataset.

Table 7 .
Partial data display.
Energies 2023, 16, x FOR PEER REVIEW 8 of 26 The fuel consumption and emission plot of 37 cars driving straight at unsignalized intersection.
g/100 km.The average fuel consumption, NOx emissions, and CO2 emissions per