Motorcycle accident risk could be inflated by a time to arrival illusion

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.

A new breed of doctor? Lessons learned and changes made to library services for the MBBS program at the University of Queensland

November 2000 saw the graduation of the first cohort from the new MBBS Program at The University of Queensland. The fully integrated problem-based curriculum has provided many challenges and opportunities for The University of Queensland Library such as servicing an extensive remote student population, information technology issues and customer demand. In October 2000 all four years of the MBBS Program completed a survey on related issues such as the library's collection, web-based resources, information skills and evidence-based medicine. This paper focuses on the results of the survey, and the future directions of the library to ensure that the new doctors graduating from this program gain the essential attributes of life-long learning, information management and evidence-based principles.