1 Introduction
By the advent of smart phone, carpooling prevails as an alternative to traditional taxi service. This mode is the practice of more than one passenger traveling in a single car. It is recognized as a solution to traffic congestion, air pollution, and other environmental and resource consequences of automobile dependence (Gheorghiu and Delhomme
[1]). However, the level of using carpooling as a travel mode has been relatively low in comparison with our expectation. In fact, carpooling has received a lot of criticism besides praise (Eriksson, et al.
[2]; Xia, et al.
[3]). To enhance carpooling acceptance, two key points are raised, what is the relationship between the acceptance of carpoolers' traveling behavior reactions
[4], and what are the critical factors impacting on their acceptance?
In literature, Shaheen, et al.
[5] investigated the effects of carpooling with heterogeneity in a dynamic equilibrium model of congestion and found the voluntary carpooling makes all users better off. Li, et al.
[6] presented an updated-LCS-based integer programming model and found the carpooling brings different comfort levels. Moreover, Bachmann, et al.
[7] discussed the difference between passengers and drivers based on established psychological theories. Our goal in this paper is to provide the correlation between travelers' acceptance and their behavior reaction to carpooling and the influence factors of the acceptance. A questionnaire survey was designed to obtain the data mainly in Beijing. Furthermore, a multi-variable regression model was developed to analyze. The main contribution of this paper are as follows. Acceptance is found to be not only related with public's "support" or "attitude" but also be strongly related with travelers' behavior reactions. Specifically, it is confirmed that lower acceptance of carpooling leads to more rejection and less sharing, weakening the effectiveness of carpooling, and vice versa. Additionally, based on previous studies, critical factors that affect the acceptance of the mode are found.
The structure of the paper is organized as follows: the background, the methodologies, a theoretical framework, the questionnaire design and the procedure and samples are presented in Section 2. The descriptive analysis, the correlation of acceptance and behavior reactions are discussed in Section 3. And Section 4 summarizes the significant findings and suggests possibilities for future research.
2 Methodology
2.1 Background: Carpooling in Main Cities, China
Carpooling means people do not need to have their own vehicles, but share vehicles with others. As the innovation of mobile internet and big date technology, carpooling plays an increasingly important role in easing urban traffic congestion and promoting green lifestyle. However, carpooling as a travel mode has been relatively low in comparison with our expectation in China. As for Beijing, the ownership of private car has increased to 3.07 million in 2018. Compared with public transportation, private cars have a very low car loading factor, which even be up to 80%, and the utilization rate is down to 20%. It is necessary to analyze travelers' carpooling acceptance and behavior reaction to enhancing carpooling attractiveness.
2.2 Theoretical Framework
There are two types of reasons influence carpooling's functions in general: One is model related factors and another is human-related factors. The model related factors refer to the criterions and rules in complementing the mode. Human-related factors include socio-economic characteristics and comprehension of individuals which have overlaps in many aspects. Then, the framework may give a good feasibility with regard to the factors related to carpooling. The structure is finally divided into three main parts mentioned below.
The first part refers to travelers' possibly associated impact factors and acceptance: Problem perception: The level to which the respondent becomes aware of the severity of traffic-related problems. Social relationship: The importance of the others' opinions for the individual. More precisely, it is respondents' perception about whether people around he/she should accept the mode and their own attitudes towards it. Knowledge: It refers to respondents' knowledge about the emerging mode. In psychological aspects, a distinction must be generated between whether a person feels well or badly. Perceived effectiveness: The degree to which the respondent thinks the effectiveness of the mode can be reached. Attribution of responsibility: Respondents' considerations about where the responsibility of traffic-related problems should be ascribed to. Perceived cost-benefit: In the context of carpooling, this refers to whether or not the respondent thinks the policy will bring more, equal, or fewer advantages compared to disadvantages in his/her daily life. Social-economic factors: Such as age, job, income, normal travel distance, and so on.
The second part is about travelers' behavior reactions to carpooling, it is demonstrated that travelers' behavior reactions are affected by the level of their acceptance, which will be proved later and classified into the following three aspects:
Willingness to carpooling: Travelers must be influenced by many reasons when they choose or don't choose carpooling such as insecurity, unexpected revenue and psychological barrier with strangers. Travel mode choices on the way to work: Travel mode choices can reflect the willingness of time and revenue car-owners have to implement the carpooling mode. We suppose that it is safe to provide carpooling service, and the passengers are randomly distributed on their way to work. With the increasing number of passengers, the time, distance, the possibility of congestion, and revenue are increasing simultaneously. Travel mode choices on the way off work: There some changes like spare time comparing with the choices on their way to work. The willingness of carpooling on their way off the work is proved to be similar according to further study.
2.3 Procedure and Sample
Based on the work of Jia, et al.
[8], the questionnaire include some modifications. All variables were set by a five-graded scale and the overview of the main questions are shown in
Table 1. The questionnaire survey was issued among both car-owners and non-car-owners online in July 2019 in Beijing. Both car-owners and non-car-owners are considered in this paper. The main purpose is to explore the influence factors of carpooling, to cut the number of solo driving vehicle and encourage more travelers prefer carpooling with others.
Table 1 An overview of the measure of variables |
| Variables | Measurement items |
| Problem perception | 1. Traffic congestion is a general problem in big cities in China.
2. Air pollution caused by the use of private car is a general problem in big cities.
Scales 1~5 (1-strongly disagree, 2-mildly disagree, 3-unsure, 4-mildly agree, 5-strongly agree) |
| Social relationship | 1. Do you think that your family and friends will support you to accept this mode?
2. What are the attitudes of your family and friends own to this mode?
Scales 1~5 (1-strongly disagree, 2-mildly disagree, 3-unsure, 4-mildly agree, 5-strongly agree) |
| Knowledge about mode | 1. Do you know the details of carpooling?
Scales 1~5 (1-know nothing, 2-a little and tried it, 3-tried it occasionally, 4-tried it sometimes, 5-know a lot) |
| Perceived effectiveness | 1. Do you think carpooling has already have an effect on reliving traffic congestion nowadays?
2. Do you think carpooling can relief traffic congestion in the future?
Scales 1~5 (1-have no effect at all, 2-have little effect, 3-have some effect, 4-work well, 5-work very effectively) |
| Attribution of responsibility | 1. To solve the problem of traffic congestion, we should develop public transportation.
2. To solve the problem of traffic congestion, we should restrict the usage of private cars.
3. To solve the problem of traffic congestion, we should encourage carpooling. |
| Perceived cost-benefit | 1. Comparing the advantage and the disadvantage brought by carpooling, your opinions are:
Scales 1~5 (1-absolutely inconvenient, 2-inconvenient, 3-unsure, 4-convenient, 5-very convenient) |
| Socio-economic factors | 1. Sex 2. Age 3. Job 4. Income 5. Normal travel distance
6. Scores to current travel modes (including bus, subway, private car, taxi and carpooling)
Scales 1~5 (1-strongly dissatisfied, 2-mildly dissatisfied, 3-unsure, 4-mildly satisfied, 5-strongly satisfied)
7. Importance to the factors associated with normal travelling/carpooling (including privacy, punctuality, security, comfort, time consuming and travelling cost)
Scales 1~5 (1-strongly unimportant, 2-mildly unimportant, 3-unsure, 4-mildly important, 5-strongly important) |
| Acceptance to carpooling | 1. Currently, what is your attitude to carpooling?
Scales 1~5 (1-strongly oppose, 2-mildly oppose, 3-neutral, 4-mildly support, 5-strongly support) |
| Willingness to carpooling | 1. Car possession 2. Car usage frequency
3. The willingness to provide/accept carpooling service
4. The factors why NOT willing to provide/accept carpooling service (including insecurity, time consuming, revenue and psychological barrier of riding with strangers)
Scales 1~5 (1-have no effect at all, 2-have little effect, 3-have some effect, 4-work well, 5-work very effectively) |
| Travel mode choices on the way TO work | Provided it is safe to provide carpooling service, please choose the best option you want among the four choices/score the 4 choices from 1~5 (higher score stands for higher satisfaction): |
| Options | Carpoolers | Normal time (minutes) | revenue (yuan) | possibility of congestion |
| Route 1 | None | 30 | -5 | 10% |
| Route 2 | One | 35 | 5 | 15% |
| Route 3 | Two | 40 | 12 | 20% |
| Route4 | Three | 45 | 17 | 25% |
| Travel mode choices on the way OFF work | Provided it is safe to provide carpooling service, please choose the best option you want among the four choices/score the 4 choices from 1~5 (higher score stands for higher satisfaction): |
| Options | Carpoolers | Normal time (minutes) | revenue (yuan) | possibility of congestion |
| Route 1 | None | 30 | -5 | 10% |
| Route 2 | One | 35 | 5 | 15% |
| Route 3 | Two | 40 | 12 | 20% |
| Route4 | Three | 45 | 17 | 25% |
3 Results
3.1 Descriptive Analysis of Acceptance and Behavior Reactions
An investigator was selected from different occupation. In total, there were 224 valid responses collected. The statistics with respondents' socio-economic factors are presented in Table 2. It can be seen that the respondents travelling by males is 40.63%. And most of the respondents aged between 18~40 years old, and most of their normal travel distance is less than 10 kilometers. Since the investigators with lower income, would prefer to carpool with others, in Table 1, general staff and students were accounted for the large proportion of the participants, and their income are mostly lower than 5000 RMB/month. The scores to the travel modes are presented in Table 3, which indicates that travelers prefer to choose subway and private car compared with carpooling.
Table 2 Respondents descriptive statistics (total=224) |
| Property | Percentage(%) | Property | Percentage(%) |
| Sex | | Job | |
| Male | 40.63 | Administrator | 13.84 |
| Female | 59.38 | General staff | 23.66 |
| Age | | Student | 27.68 |
| < 18 | 2.68 | Individual business | 18.75 |
| 18~25 | 29.46 | Worker/Farmer | 3.13 |
| 26~40 | 28.57 | Others | 12.95 |
| 41~60 | 37.95 | Income (RMB /month) | |
| > 61 | 1.34 | 0~3000 | 37.5 |
| Normal travel distance | | 3001~5000 | 24.11 |
| 0~5 km | 53.13 | 5001~10000 | 24.55 |
| 5~10 km | 33.48 | > 10000 | 13.84 |
| > 10 km | 13.39 | | |
| *RMB: The official currency of China |
Table 3 Scores to current travel modes |
| Option | Scores |
| Bus | 3.46 |
| Subway | 3.67 |
| Private car | 3.76 |
| Taxi | 3.42 |
| Carpooling | 3.47 |
The important factors associated with normal travelling and carpooling are presented in Table 4, be opposite to the factor of comfort, security is always the most important factor, regardless of travel behaviors. Moreover, the scores for carpooling are always lower than that of the normal travelling, which indicates that travelers have a lower desire to carpooling. The descriptive statistics relating to acceptance are presented in Table 5. It can be seen that the "strongly support" and "mildly support" is proximately 67.30%, but quite a few respondents stood neutrally, which means there are still many people uncertain about the effect of carpooling.
Table 4 Importance to the factors associated with normal travelling/carpooling |
| Factor | Grades |
| Normal travelling | Carpooling |
| Privacy | 4.25 | 3.79 |
| Punctuality | 4.50 | 4.02 |
| Security | 4.69 | 4.13 |
| Comfort | 4.17 | 3.79 |
| Time consuming | 4.32 | 4.00 |
| Travel cost | 4.13 | 3.66 |
Table 5 Acceptance of the carpooling mode |
| Attitude | Percentage | Mean | S.D. |
| Strongly support | 14.73 | | |
| Mildly support | 53.57 | | |
| Neutral | 28.13 | 3.79 | 0.73 |
| Mildly oppose | 3.57 | | |
| Strongly oppose | 0 | | |
3.2 Factors Impacting Acceptance
In this section, a multi-variable regression model is employed to analyze the correlation between the influencing factors and acceptance presented in Subsection 2.2. The findings are presented in Table 6, where stands for the standard coefficients and stands for the results of the -test. The independent variables are calculated as in Table 2. The dependent variable "acceptance" is calculated by their scores directly. The overall regression is statistically significant due to a -value of 0.0000.05. Meanwhile, the model is well-fitted with the high level of =0.608. It can be seen that the factors positively influencing travelers' acceptance of the carpooling are sequentially: Social relationship, knowledge, perceived effectiveness, attribution of responsibility and perceived cost-benefit, whilst problem perception has a negative influence in acceptance.
Table 6 Multi-variable regression analysis of the acceptance |
| Predictor variables | | | Sig. |
| Problem perception | -0.118 | -2.44 | 0.015 |
| Social relationship | 0.211 | 3.97 | 0.000 |
| Knowledge | 0.102 | 3.17 | 0.002 |
| Perceived effectiveness | 0.196 | 3.50 | 0.001 |
| Attribution of responsibility | 0.310 | 4.73 | 0.000 |
| Perceived cost-benefit | 0.226 | 4.83 | 0.000 |
| Constant | 0.461 | 1.97 | 0.142 |
Attribution of responsibility, perceived cost-benefit and perceived effectiveness are the important factors, which are positively correlated with the acceptance. Compared with the result in variable "Knowledge" which influences "Acceptance" slightly weakly, it is easy to speculate that even if travelers know little about carpooling, as the understanding on the effect of traffic congestion alleviation, they gradually have a higher acceptance of carpooling. This indicates that most travelers are willing to improve the environment with high sense of responsibility.
Not surprisingly, social relationship is positively correlated with the acceptance strongly. It is understandable that travelers are accustomed to being influenced by public opinions, especially by relatives, because our traditional culture always encourages us to listen to others.
Differently from the original, problem perception in unexpected negatively correlated with the acceptance strongly. Looking through the survey data, it is found that most respondents chose "mildly agree" and "strongly agree" to the two questions. It is suspected that this may be caused by the specific characteristic of carpooling, which is still a kind of private car using. Therefore, with the highly agreeable of prevailing congestion, private car overusing and little knowledge of the mode, carpooling based on private car may not be supported as expected. However, we can speculate by the following variables that they are willing to relief the congestion by carpooling, it is feasible to popularize the exact cognition and utility of the mode.
3.3 The Correlation Between Acceptance and Behavior Reactions
This section first focuses on the willingness to carpooling. The respondents were divided into two groups: Car-owners and non-car-owners, and the ratio is presented in Table 7. From the descriptive statistics presented in Table 8, it can be seen that a large proportion of car-owners are unwilling to provide carpooling service and non-car-owners turn reverse. The reasons of car-owners' unwillingness are list in Table 9, and the major one is psychological barrier of carpooling with strangers and the second is much time consuming. Since most of the car-owners have a higher-level job with higher income and more strict limited time, it is consistent with the common sense. As to non-car-owners, their concern focuses on insecurity, which means the accident presents a significant effect on carpooling behavior.
Table 7 The condition of respondents about car-owning |
| Option | Percentage |
| Car-owners | 68.3 |
| Non-car-owners | 31.7 |
| Car usage frequency (only car-owners) | |
| Never | 0.65 |
| Hardly | 1.96 |
| Sometimes | 20.26 |
| Often | 60.13 |
| Always | 16.99 |
Table 8 Willingness to provide (car-owners)/accept (non-car-owners) carpooling |
| Option | Percentage |
| Car-owners | |
| Yes | 36.6 |
| No | 63.4 |
| Non-car-owners | |
| Yes | 78.87 |
| No | 21.13 |
Table 9 Scores to reasons why people don't want to provide/accept carpooling service |
| Car-owners | Grades | Non-car-owners | Grades |
| Insecurity | 3.76 | Insecurity | 4.13 |
| Time-consuming | 3.93 | Time-consuming | 3.67 |
| Revenue | 3.53 | Revenue | 3.73 |
| psychological barrier of riding with strangers | 4.09 | | |
Secondly the willingness of car-owners under different circumstances was investigated in Table 10. In conclusion, whenever is on or off their way to work, the respondents prefer to catch less clients. Despite of this, their willingness to catch more people don't increase when they are on their way off work, possibly because of tiring work at daytime. And the revenue to car-owners is more unimportant compared with time consuming and other possible reasons, which has a corresponding to the former conclusion in Subsection 3.3.
Table 10 Travel mode choices on the way to/off the work |
| Route | Percentage (%) |
| To work | Off work |
| 1 | 49.02 | 37.91 |
| 2 | 32.68 | 30.72 |
| 3 | 13.73 | 19.61 |
| 4 | 4.58 | 11.76 |
4 Conclusion and Discussion
In this study, a connection between the acceptance and effectiveness of carpooling was confirmed firstly. Since the acceptance is not merely an indicator of travelers' attitudes, and it is also the key factor relating to travelers' behavior reactions. Thus, it is a critical point for us to improve travelers' acceptance. In a word, the benefits are as following.
(a) As to car-owners, higher acceptance indicates there will be more switch to provide carpooling service. On the other hand, higher acceptance suppresses negative impacts of carpooling on car-owners who use their cars less, and they may turn to choose to provide carpooling service with a substantial revenue, which may relief the congestion of public transportation.
(b) It will be a new mode to non-car-owners. In previous time, they have to catch the public transportation earlier, taking the late hazard. However, carpooling can provide a reservation service and a more comfortable environment as long as they are willing to use it.
(c) Authorities like government and companies can make it as a new profit mode based on a larger range of travelers who have higher acceptance. With the development of internet, carpooling itself has a bigger possibility to be promoted.
Secondly, several factors which impact on the acceptance is found, and then some suggestions are proposed as follows.
(a) Since their specific characteristics, individuals' social relationship, attributions of responsibility and knowledge can't be changed directly. However, we can use different ways such as public education, it can improve the awareness of carpooling's effectiveness in traffic congestion. The critical point here is to let both car-owners and non-car-owners understand the emergency to find a feasible way to overcome the problem in a more environmental and energy-saving way.
(b) The finding that the problem perception is a negative factor implied that the mode should be understood by public more correctly. This mode can only be implemented efficiently when it is properly understood otherwise it will be thought redundant even be against.
(c) The benefits, such as the effectiveness of carpooling in reliving traffic congestion is a priority for earning the public's acceptance. Therefore, the regulations of carpooling should be carefully designed, such as the revenue and the compensation when it fails to avoid bad effectiveness.
(d) A general suggestion is to combine carpooling with both car-owners and non-car-owners. The car-owners willingness can directly impact the usage of unnecessary private cars. If they can accept this way to replace their private car sometimes (such as restrict days), the effectiveness may quickly show. Another suggestion is to encourage non-car-owners to use carpooling instead of using public transportation in some occasions in order to relief the congestion.
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Table 1 An overview of the measure of variables
