Position of car indicator lights affects safety

March 22nd, 2007 in Medicine & Health / Psychology & Psychiatry

People find it harder to make rapid decisions about which way a car will turn if its amber indicator lights are inside the headlights (i.e. nearer the middle of the car) than if the indicator lights are outside the headlights, according to research published today in the Journal of Applied Cognitive Psychology.

The indicators on cars are critical safety features that enable pedestrians and other road users to predict where a car is likely to go in the next few seconds. The difference in reaction times is enough to make a significant impact on safety.

"Several modern cars position the right indicator to the left of the right headlight and the left indicator to the right of the left headlight, and this study shows that this design feature could reduce their safety," says Andrew Bayliss, who carried out the research.

The research was carried out using two groups of 15 young adults at the School of Psychology at the University of Wales, Bangor where Dr. Bayliss works. They were shown pictures of the fronts of cars and asked to press a button on the left of the keyboard as quickly as they could if the light on the left of the car flashed, and a button on the right if the right light flashed. [See Figure 1 - attached]

The students responded significantly faster to cars where the indicator lights were outside the headlights, than when they were placed inside.

Furthermore, Bayliss believes that the effect could be greater for older people or for people in real world situations that have more distractions than the students faced in the trials.

"Designers obviously want to create good looking cars, but this should not be done at the expense of compromising safety. The position of lights on the car should be guided by safety considerations – not aesthetics," says Bayliss.

Source: John Wiley & Sons, Inc.

"Position of car indicator lights affects safety." March 22nd, 2007. http://phys.org/news93759694.html