Crossing a Multi-Lane Street: Irrelevant Cars Increase Unsafe Behavior

Before crossing a road or an intersection, road users have to determine among the surrounding traffic whether or not they have enough time to safely complete their maneuver. Temporal judgments have been investigated for single cars approaching an intersection, however, close to nothing is known about how street-crossing decisions are being made when several vehicles are simultaneously approaching in two adjacent lanes. We conducted a simulator experiment in which observers indicated whether or not they had enough time to complete safe street crossing. Traffic gaps were presented either with a single or two oncoming cars on different lanes, in such a way that in all cases, only the shortest gap was taskrelevant. Nevertheless, street-crossing decisions were found to be also influenced by the task-irrelevant longer gap, observers being more willing to cross the street when having to judge two gaps simultaneously compared to only one gap. Consequences of this unsafe behavior are discussed.