Abstract
The objective of this research is to improve drivers´ decision making in
selecting a lower driving speed for the purpose of decreasing the risk and the severity of
traffic accidents. Our research focused on the speedometer, in other words, on speed
information display. Two working hypotheses were formulated to resolve this issue. One was
that an alert to call for the driver´s attention to a speed information display when the speed
exceeds a predetermined value would decrease driving speed. Another was that a speed
display whose scale is proportional to the square of speed would decrease driving speed.
These hypotheses were tested with a driving simulator study. The experimental results
showed that the average speed decreased by 3% and the maximum speed decreased by 4%
when speed information was displayed on the scale proportional to the square of speed for a
fast-driver group. These results demonstrated the possibility for a speed information display
to improve driver decision in selecting safer speeds to decrease the risk and the severity of
traffic accidents.
Keywords - Speed, display, Information, decision-making, human factors