SCIENCE FILE : Science in Brief : Optical Illusion May Prompt Drivers to Change Lanes, Scientists Say

The urge to change lanes while driving may be caused by an optical illusion that convinces people the cars in the other lane are going faster, scientists report in today’s Nature. The basic problem is that cars spread out when they’re going quickly and bunch up when they slow down, said Donald Redelmeier of the University of Toronto. So when you pass a bunch of slower cars in the other lane, it happens fairly quickly. But if you are passed by the same cars while your lane slows temporarily, they go by one by one.

Computer simulations showed that a driver can spend more time being overtaken by cars in the other lane than in passing them, even though both lanes travel at the same average speed. That leads to the illusion that the other lane is moving faster, the researchers said.

Compiled by Times medical writer Thomas H. Maugh II