Factors Affecting Drivers to Participate in a Carpooling to Public Transport Service
2. Literature Review
3.1. Data Collection
- The first section included questions on general and sociodemographic characteristics, such as home country, gender, age, income, educational level and professional status.
- The second section provided the definition of carpooling and three more questions relative to carpooling, such as the participant’s area of residence (i.e., urban, semi-urban or rural), ownership of a smartphone and previous experience with carpooling services. Respondents without previous carpooling experience were forwarded directly to the following section, whereas respondents with previous carpooling experience were first directed to answer four additional questions to rate their last carpooling experience, their trip purpose, with whom they travelled and the modes they selected to use together with carpooling in their last journey (if any).
- The third section concerned the participant’s travel habits by focusing on a usual journey of theirs.
- The fourth section was available only to passengers concerned the utilization of carpooling and public transport (e.g., rail, tram or metro). In this section, the respondents were introduced to the hypothetical scenario. The scenario stated: “For this journey you are carpooling as a passenger and you are using a mobile app to plan your journey. Through the app you are able to find a driver and arrange a carpooling to take you to/from the rail/metro/tram station to complete the first/last-mile of your journey.” A set of questions followed for passengers.
- The fifth section was available only to drivers (i.e., driving license holders and car owners), and it concerned the reasons why potential drivers would accept to use their personal vehicle the presented scenario. The section started with the statement: “Now as a driver let’s imagine you can use your car to provide carpooling services to other travelers. If the mobile application could suggest you carpooling passengers; you would accept a journey if…”. Nine questions followed (Table 1) that represented nine potential factors for drivers. These questions represent factors that were identified in the literature as significant for passengers and drivers, including the number of passengers to travel with, travel companion, incentives (i.e., parking offer), travel factors (i.e., maximum number of pickup points, delay, time and cost of trip) and ride security.
- The conversational survey targeted EU-based travelers. The survey link was sent to the participants using multiple dissemination channels, including social media (i.e., LinkedIn, Facebook, Twitter), emails and professional newsletters. Participants included transport research institutions, ministries, educational institutes and companies.
3.2. Statistics and Modelling
4.1. Carpooling Drivers
- The maximum number of passengers to offer the journey to did not seem to be equally shared among the three options (one, two and three passengers).
- Drivers preferred to travel with friends (30%), family (29%) and coworkers (28%) compared to strangers (13%). Trust was revealed as an important issue through this question.
- Drivers were reluctant to offer carpooling services during the night and almost equally eager services during the rest of the day.
- The two factors related to parking (“Parking offer” and “Lack of parking”) were both rated with five stars by the majority of drivers, showing that the provision of a parking place is important for the drivers. Discounted parking seems to be a good incentive to convince drivers to join a carpooling application.
- The majority of the drivers preferred to check the passenger’s profile using the carpooling application (45%) and Facebook (40%).
- The majority of the drivers preferred to reduce the cost of their journey by EUR 2–3 (41%), while they were ready to accept an overall delay to their journey of 3–5 min (42%). It seems that the cost reduction should be at least EUR 2 to engage more drivers.
- One pick-up/drop-off point was clearly preferred by 64% of drivers, as it was rated five and four stars.
4.2. Statistics and Exploration
4.3. Statistical Modelling
- A positive coefficient of “Delay” (Number of minutes I would accept to add to my journey) demonstrates that drivers who would accept a longer delay are more likely to use carpooling services to public transport. Most of them would accept a maximum delay of 3–5 min. The overall amount of delay that they would add to their journey is a determining factor that may persuades these drivers to participate in carpooling services. Drivers who would accept a delay of 6 or more minutes are 2.035-times more likely to use carpooling services than drivers who would accept a maximum delay of 5 min or less. Therefore, a carpooling system should attempt to minimize delay to attract more drivers and increase the use of the carpooling service.
- Similarly, the factor “Convenience” (If I could use only one pick-up/drop-off location for all passengers) appeared to be significant. Drivers who answered with four and five stars (i.e., agree and strongly agree) are 2.210-times more likely to join carpooling services than drivers who answered with three or less stars (i.e., strongly disagree, disagree and neutral). Therefore, carpooling is more popular when planning for the minimum number pick-up/drop-off locations for passengers.
- Regarding the location of residence, drivers that answered suburban and rural in the question (Do you live in an urban or a rural/semi-urban area?) are 0.530-times more likely to join carpooling than drivers that answered urban. Therefore, carpooling services with public transport services tend to be more popular among drivers who live in suburban and rural areas, and such services should be initially deployed in these areas.
- For the factor “Security” (ability to check the passengers’ profile), the positive coefficient (1.147) in the question “I could be able to check the passenger’s profile in carpooling application” shows that drivers would prefer to use the carpooling application that they registered with to review the passenger’s profile. Having a carpooling application to check the passengers’ profile is strongly associated (odds ratio = 1.672) with carpooling services.
- The factor “Passenger number” was also found to be significant in the model, showing that drivers who prefer to travel with two or three passengers are 2.175-times more likely to use carpooling services than those that who prefer to travel with one passenger, probably due to security reasons. Therefore, carpooling matching algorithms should be developed to arrange rides with at least two passengers.
5. Discussion and Conclusions
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
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|Max number of passengers I could share the journey with||Passenger number||Single choice|
|Travel preference in terms with whom I would rather travel||Travel companion||Multiple response|
|Time of the day to offer the journey||Daytime||Multiple response|
|I could get a free or discounted parking at my destination||Parking offer||1–5-star rating *|
|There is a shortage of parking for my car at my destination||Lack of parking||1–5-star rating|
|Ability to check the passengers’ profile||Security||Multiple response (max. 2)|
|Amount by which I could reduce my journey’s cost||Journey cost||Single choice|
|I could use only one pick up/drop off location for all passengers||Convenience||1–5-star rating|
|Number of minutes I would accept to add to my journey||Delay||Single choice|
|Age||Less than 18||56||17.1|
|More than 65||56||17.1|
|Master’s degree or higher||191||58.4|
|Prefer not to say||5||1.5|
|Occupation||Employed full time (40-more hours/week)||208||63.6|
|Employed part time (max 39 h/week)||15||4.6|
|Unemployed and looking for a job||3||0.9|
|Unemployed and not looking for a job||4||1.2|
|Unable to work||3||0.9|
|Prefer not to say||6||1.8|
|Past carpooling experience||Yes||176||53.8|
|With family members||279||28.0|
|Passenger number||1 Passenger: 31%|
2 Passengers: 39%
3 Passengers: 30%
|Travel companion||Strangers: 13%|
|Parking offer||1 star: 5.5%|
2 stars: 7%
3 stars: 10.4%
4 stars: 25.4%
5 stars: 51.7%
|Lack of parking||1 star: 17.7%|
2 stars: 11.6%
3 stars: 22.9%
4 stars: 18%
5 stars: 29.7%
|Security||Carpooling app: 45%|
Governmental ID: 15%
|Journey cost||EUR 1: 9.2%|
EUR 1–2: 15%
EUR 2–3: 40.7%
EUR 4 or more: 35.2%
|Convenience||1 star: 0|
2 stars: 8%
3 stars: 27.5%
4 stars: 26.6%
5 stars: 37.9%
|Delay||3 min: 13.1%|
3–5 min: 42.2%
5–8 min: 25.4%
8–12 min: 19.3%
|Variable||Description||Fishers’s Exact Test (p-Value) for Carpooling Drivers/Non Drivers|
|Security||Dummy: not using an app (0); using an app (1)||0.000|
|Delay||Dummy: 0–5 min (0); 6 and more (1)||0.001|
|Residence||Dummy: rural and suburban (0); urban (1)||0.034|
|Convenience||Dummy: Strongly disagree, disagree, neutral (0); agree, strongly agree (1)||0.049 *|
|Passenger no.||Dummy: 1 passenger (0); 2 and 3 passengers (1)||0.000|
|B||S.E.||Sig.||Odds Ratio||95% C.I.|
|Summary of statistics|
|Cox and Snell’s R2||0.124|
|1||Trust is revealed as an important issue-drivers prefer to travel with friends (30%), family (29%) and coworkers (28%).||Provide the ability to check the potential passengers’ ID through the application and other means, such as Facebook and other social media profiles and/or governmental ID.|
|2||Drivers are reluctant to offer carpooling services during the night, and almost equally eager during the rest of the day.||Drivers should be able to state if they are willing to provide services during night time; if not, no penalty of any kind should be imposed.|
|3||Drivers would prefer to check the passenger’s profile by using the carpooling application and Facebook. Having a carpooling application to check the passengers’ profile is strongly associated with carpooling services.||The provided service should be available through a smartphone application.|
|4||Expected reduction of travel costs: EUR 2–3.||The provided services should prove in some way that the specific type of travel will ensure the reduction of cost by at least EUR 2–3 compared to the alternative mobility option. Monetization of external costs such as time could be considered to achieve this objective.|
|5||Accepted increase in travel time: 3–5 min.||Trip time for carpooling drivers should not be increased more than 3–5 min. Young and older drivers accept higher time increases.|
|6||One pick-up/drop-off point is preferred.||Provision of services entailing only one pick-up and drop off point.|
|7||Preferred number of passengers is 2.||The same trip should be provided to no more than 2 passengers at the same time, so the maximum number of passengers in the car is 3 including the driver. In the case of a female driver, a special care should be provided to arrange rides optimally with 2 passengers.|
|8||Reception of parking discounts or free passes “could do the trick”, especially for middle-aged people.||The application should provide various financial incentives to increase the number of people eager to provide carpooling services. Such incentives include booking of parking spots, parking discounts and/or free passes in parking lots.|
|9||Young and older drivers could accept a higher increase in travel time more easily.||The overall ride time should not be more than 15 min. So provided services should be designed and scheduled to minimize in-vehicle time.|
|10||Carpooling services with public transport services are more popular to drivers that live in non-urban areas.||Provide alignment of carpooling services with PT schedules.|
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Mitropoulos, L.; Kortsari, A.; Ayfantopoulou, G. Factors Affecting Drivers to Participate in a Carpooling to Public Transport Service. Sustainability 2021, 13, 9129. https://doi.org/10.3390/su13169129
Mitropoulos L, Kortsari A, Ayfantopoulou G. Factors Affecting Drivers to Participate in a Carpooling to Public Transport Service. Sustainability. 2021; 13(16):9129. https://doi.org/10.3390/su13169129Chicago/Turabian Style
Mitropoulos, Lambros, Annie Kortsari, and Georgia Ayfantopoulou. 2021. "Factors Affecting Drivers to Participate in a Carpooling to Public Transport Service" Sustainability 13, no. 16: 9129. https://doi.org/10.3390/su13169129