Interaction between Cyclists and Motor Vehicles : the role of infrastructure design and vehicle characteristics

The aim of the project was to examine interactions between motor vehicle drivers and cyclists at intersections and the impact of infrastructure design and motor vehicle characteristics on interactive behaviour. The project activities included literature reviews on cycling infrastructure at intersections, vehicle driver behaviour and cyclist behaviour; questionnaires among motor vehicle drivers and cyclists across different cities in Sweden; field observations to investigate what cues cyclists use to interpret the intention of motor vehicles they interact with at signalised intersections; on-site interviews with cyclists to explore their strategy in an encounter with a motor vehicle; and a cycling simulator study to examine the behaviour of cyclists when approaching an intersection and the factors that may influence their decisions. The findings confirm that the way the cycling infrastructure is designed at intersections contributes to how cyclists and motor vehicles interact. Placing cyclists and motor vehicle drivers close (where they are visible to one another) at intersection areas increases the level of presence-awareness for both road users and consequently it increases safety. Though cyclists may feel more uncomfortable (exposed and unsafe) with this solution, they tend to be more careful and attentive. This finding from the literature was confirmed by the field observations showing that mixed traffic, i.e. “no cycle facility” at the intersection is the safest solution and the cycle lane solution is the least safe one. However, the on-site interviews with cyclists revealed that the large majority of the respondents preferred the infrastructure solution with a separated bicycle path. This is a typical case where objective safety and subjective safety stand in opposite relationship. The findings also revealed that one-directional cycle tracks enhance interaction at intersections, since motor vehicle drivers only expect cyclists from one direction. However, cyclists not following the rule and riding against the prescribed direction create problems and conflictive situations. Cyclists and the way they use the road infrastructure were found to be highly heterogeneous; the availability of cycling infrastructure at an intersection does not guarantee that cyclists use it as expected by designers and perhaps by motor vehicle drivers, as the infrastructure solution in some cases might not provide the shortest path for the cyclist. The uncertainty in cycling behaviour was found to be more at intersections with no cycling infrastructure. Confidence level among cyclists was found to affect their interaction with motor vehicles which tends to be hard for motor vehicle drivers to predict as different cyclists behave differently depending on their confidence in traffic.The majority of the interviewed cyclists said that when arriving at an intersection just after a motor vehicle they usually pass it on its right side. This was seen in observations on sites with cycle lane or cycle path but not on sites with mixed traffic. Also, if the motor vehicle was a heavy vehicle (bus or truck), somewhat fewer cyclists passed it on its right side. Also the cycling simulator study revealed that the most significant difference of longitudinal stop position was between the condition of a narrow lane without cycle lane marking and a truck standing at the stop line and the condition of wide lane with cycle lane marking and a car standing at the stop line, where the average stop position of the cyclist was behind the truck in the first condition and next to the car in the second condition. This finding corresponds to the test cyclists’ verbal expressions of the importance of “being visible and avoiding the blind spot”. The increased caution associated with the presence of a truck is motivated and in line with previous studies. At sites with mixed traffic (no cycle facility), compared to with cycle lane or cycle path, the cyclists’ scanning behaviour was more complete. At sites with cycle path, the cyclists looked for eye contact with the driver of the motor vehicle to a much larger extent than cyclists at the other two types of sites. Cyclists at sites with mixed traffic (no cycle facility) were more active in their visual search behaviour than cyclists at the other two types of sites. Also, those cyclists who passed the motor vehicle on its right side were more active in their visual search behaviour than those who did not pass the motor vehicle. The share of critical situations indicates that sites with mixed traffic (no cycle facility) is the safest solution and cycle lane solution is the least safe one. (Less)