Can Information About an Approaching Bicycle’s Characteristics Influence Drivers’ Gap Acceptance and TTA Estimates?

Abstract

E-bikes, which have the potential to reach higher speed levels than conventional bicycles, but look basically the same, are suspected to be at a higher crash risk than such conventional bicycles. Other road users might misjudge the time remaining before the approaching bicycle arrives (time to arrival, TTA) and accept unsafe gaps (e.g. for turning manoeuvres) as a result of this combination of higher speed and well-known looks. Researchers have therefore suggested to make drivers aware of the higher speed of e-bikes, and give e-bikes a distinct appearance. Goal of this experiment was to investigate the effects of such a unique appearance, coupled with clear instructions about the capabilities of ebikes, on gap acceptance and TTA estimates. Participants were presented with video sequences of approaching cyclists clearly identifiable as either riding a conventional bicycle or e-bike, and were required to either indicate the smallest acceptable gap for a left turn in front of the cyclist, or to estimate TTA in two different experimental blocks. The results showed no difference in accepted gap size between the two appearances of the cyclist, whereas there was a minor effect on TTA estimates. Overall, the results imply that simply informing other road users about e-bikes (in conjunction with a re-design that gives them a unique appearance), might not be sufficient to elicit a more conservative behavior.