Time to Arrival Estimates, (Pedestrian) Gap Acceptance and the Size Arrival Effect

Various studies have found that road users’ acceptance of gaps to cross in front of another vehicle is dependent on the approaching vehicle’s size, with smaller accepted gaps in front of smaller vehicles. At the same time, the so called size arrival effect is well known from research on time to collision / time to arrival estimates, where larger objects / vehicles tend to be judged as arriving earlier than smaller objects / vehicles. However, so far there has been no attempt to connect these two approaches in a single experiment to investigate whether the size arrival effect that is prevalent in time to arrival estimates can explain the variations in gap acceptance. In this experiment, twenty-seven participants observed video clips of approaching virtual vehicles of varying size (truck, bus, van, two different cars and a motorcycle) from a pedestrian’s perspective, and were either required to indicate a crossing decision, or to estimate time to arrival. While, overall, the effect of vehicle size was clearly visible for both crossing decision and time to arrival estimates, there was also a clear exception in the form of the motorcycle, which went with larger accepted gaps than some of the larger vehicles. This exception might be explained by the participants’ subjective rating of perceived threat, which was rather high for the motorcycle. As (with the exception of the motorcycle), vehicle size and perceived threat correlated substantially, it is unclear at this stage to what degree these two factors contribute to perceived time to arrival and crossing decisions.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References;
  • Pagination: pp 44-50
  • Monograph Title: Driving Assessment 2017: Proceedings of the 9th International Driving Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design

Subject/Index Terms

Filing Info

  • Accession Number: 01664192
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 21 2018 1:26PM