Keywords

1 Introduction

Aggressive driving is considered to be associated with road accidents and it is therefore actively studied in the scope of traffic safety [1]. It manifests as a behavior and as such is related to the inner or psychological state of the driver [2]. There are multiple definitions of aggressive driving. Some focus on whether the aggressive behavior is deliberate [3] or on the driver’s negative feelings [4] or motives. In most cases, behaviors involved in aggressive driving constitute traffic violations such as speeding and tailgating. The consequence of such behaviors may be endured by any road user including other car drivers, pedestrians and cyclists.

Cycling in particular is a desirable means of urban transport because it promotes sustainable mobility. Still, cycling and cyclists remain largely marginalized [5]. A number of motorists do not seem to accept or tolerate the increasing number of cyclists on the road and tend to hold a negative attitude toward them. Cyclists have an equal right to use the road while at the same time constitute a special group of road users with different characteristics and needs [6]. As previously mentioned, aggressive driving is related to the psychological state of the driver. In this context, certain values drivers hold and their attitude toward other road users become relevant. For example, one could expect that a motorist who values equality in general, would likely consider a cyclist’s equal right to use the road.

It must be mentioned at this point that research on the above mentioned topics has been conducted in the School of Civil Engineering and in the School of Rural and Surveying Engineering of the Aristotle University of Thessaloniki during the last years [7,8,9,10,11,12,13]. Specifically, the interaction between drivers, cyclists and pedestrians has been investigated in the road environment of Thessaloniki in order to identify and better understand road users’ behavior. Within the framework of this paper the focus was set on aggressive driving, driver attitude towards cyclists and driver personal values.

2 Methodology

Car drivers participated in a supervised self-completion questionnaire survey that was conducted in 2015 in Thessaloniki [13]. The average completion time was 6 min and a total of 140 questionnaires were completed. The questionnaire consisted of 32 items grouped into four sections: (a) aggressive driving toward other road users, (b) driver personal values and attitude toward cyclists, (c) questions related to cycling in general and (d) general scope and socioeconomic characteristics. The collected data were screened for incomplete cases, outliers and unengaged responses and were analyzed using IBM SPSS 19 software.

In Table 1, every different type of aggressive driving behavior constitutes a traffic violation according to the Greek Highway Code. This is true even for behaviors that might be considered “not so serious” and the respective rule is hardly ever enforced, such as honking the horn immediately at a green light signal or blocking the pedestrian crossing during a red light signal. A short description of each variable along with their binary values is presented. Following in Table 1, description and values of the variables related to driver attitude toward cyclists and driver personal values are presented. The first two items relating to driver attitude toward cyclists were intentionally formulated as faulty generalizations and express a prejudiced opinion. Obviously, not all cyclists behave this way. Items relating to driver personal values originated from the supplementary questionnaire of European Social Survey, a 21-item measure of human values [14]. Also in Table 1, description and values of the variables related to cycling in general are presented. Variables DMCycl and AccCar derived from conditional items of the questionnaire and were filled in by car drivers who stated they also cycle or had been cycling.

Table 1. Description and values of variables denoting aggressive driving, attitude towards cyclists, driver personal values and items related to cycling.
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Finally, description and values of general scope variables are presented in Table 2. Items in this section of the questionnaire included driver’s road safety awareness and information, driving experience as well as socioeconomic items. Household income was presented as an optional question to the participants.

Table 2. Description and values of the general variables.
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3 Descriptive and Inferential Statistics

3.1 Summary Statistics

For the binary variables of the survey the proportion of the drivers who responded “yes” is presented in Table 3. Despite the fact that 77% of the drivers reported to be aware of the increased road accidents in Greece, percentages for the various types of aggressive driving were considerable. It is worth noting that only 59% were aware of the default urban speed limit (50 km/h); a supposedly well-known piece of traffic rules information.

Table 3. Summary statistics of binary variables.
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In regard to driver attitude towards cyclists, considerable percentages that indicate a negative attitude were found and they are presented in Table 4. Especially, in Attitude3: “Cyclists should not be on the road”, a combined 66% of the participants responded either “Fully agree” or “Agree”. On the contrary, drivers responded mostly in favor of the presence of cycle lanes. Attitude4: “Cycle lanes take up car space”, received a combined 73% of either “Disagree” or “Fully Disagree”.

Table 4. Percent frequencies of Education.
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In regard to drivers’ personal values (see Table 4), percent frequencies show that drivers mostly identified as persons who value safety, equality and tolerance. However, percent frequencies for those who like to take risks are also sizeable.

Half the drivers (N = 70) reported they also cycle or had been cycling. The majority of the participants hadn’t had an accident either as car drivers with a cyclist or as cyclists with a car (see Table 4). About one fifth (21%) of the drivers do not consider cycling as a possibility at all (see Table 4). Also, almost half the drivers (49%) reported they had watched a road safety campaign during the previous month.

Summary statistics for the rest of the variables of the survey that are continuous are presented in Table 5.

Table 5. Summary statistics of continuous variables.
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3.2 Bivariate Associations

Associations between variables from the sections of aggressive driving, driver attitude toward cyclists and driver personal values are presented in Table 6. Only significant associations at the .05 level are presented. Since the variables were measured at different levels, phi coefficient was utilized for associations between two binary variables, rank biserial coefficient between a binary and an ordinal variable and Spearman’s rho correlation coefficient between two ordinal variables.

Table 6. Statistically significant bivariate associations between variables denoting aggressive driving, driver attitude towards cyclists and driver personal values.
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4 Conclusions

A considerable proportion of the drivers that participated in the questionnaire-based survey stated that they drive aggressively. The most common behaviors were speeding (56%) and tailgating (68%). In comparison to the literature, a report on aggressive driving in Canada [15] found that roughly 60% of the drivers were driving in excess of the posted speed limit.

The participants of the study claimed that cyclists are dangerous drivers (56%) with no respect for the traffic rules (47%) and should not be allowed to use the road space (66%). These results are in accordance with a previous study that argues cycling remains marginalized [5]. Most drivers (73%) didn’t regard cycle lanes as facilities that take up car space. Concerning personal values, drivers tended to value safety (85%), equality (96%) and tolerance (92%). However, a sizeable proportion (41%) was in favor of taking risks.

The bivariate correlations that are presented in this paper simply provide a useful indication for further investigation into the true nature of the relations between such data. Many interrelationships between items from the questionnaire’s sections of aggressive driving, driver attitude toward cyclists and driver personal values were found statistically significant. The largest effect sizes were found to be those between ValEqual and ValDiffer, rs(138) = .65, p < .00, Attitude1 and Attitude2, rs(138) = .58, p < .00, and ValSafe and ValEqual, rs(138) = .40, p < .00. Furthermore, the statistically significant correlations between the different types of aggressive driving are in accordance with previous research [16], in which it is shown that drivers who engage in one type of aggressive driving behavior are also likely to engage in other types of aggressive driving behavior.