Optometry & Vision Science

Skip Navigation LinksHome > August 2005 - Volume 82 - Issue 8 > Motorcycle Accident Risk Could Be Inflated by a Time to Arri...
Optometry & Vision Science:
Original Article

Motorcycle Accident Risk Could Be Inflated by a Time to Arrival Illusion

HORSWILL, MARK S. PhD; HELMAN, SHAUN PhD; ARDILES, PABLO MSc; WANN, JOHN P. PhD

Collapse Box

Abstract

Purpose. Drivers adopt smaller safety margins when pulling out in front of motorcycles compared with cars. This could partly account for why the most common motorcycle/car accident involves a car violating a motorcyclist’s right of way. One possible explanation is the size–arrival effect in which smaller objects are perceived to arrive later than larger objects. That is, drivers may estimate the time to arrival of motorcycles to be later than cars because motorcycles are smaller.

Methods. We investigated arrival time judgments using a temporal occlusion paradigm. Drivers recruited from the student population (n = 28 and n = 33) saw video footage of oncoming vehicles and had to press a response button when they judged that vehicles would reach them.

Results. In experiment 1, the time to arrival of motorcycles was estimated to be significantly later than larger vehicles (a car and a van) for different approach speeds and viewing times. In experiment 2, we investigated an alternative explanation to the size–arrival effect: that the smaller size of motorcycles places them below the threshold needed for observers to make an accurate time to arrival judgment using tau. We found that the motorcycle/car difference in arrival time estimates was maintained for very short occlusion durations when tau could be estimated for both motorcycles and cars.

Conclusions. Results are consistent with the size–arrival effect and are inconsistent with the tau threshold explanation. Drivers estimate motorcycles will reach them later than cars across a range of conditions. This could have safety implications.

© 2005 American Academy of Optometry

Login

Article Tools

Share

Article Level Metrics

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.