Effectiveness of a headway measuring and recording device was evaluated in terms of its ability to increase drivers' car-following distance. 43 drivers first drove for approximately 3 weeks without headway feedback and then for approximately 3 more weeks with immediate time headway (THW) feedback. Whenever the THW decreased to 1.2 s or less a red warning light came on, and whenever the THW decreased further to 0.8 s or less a buzzer was also sounded. Results show that prior to receiving THW information, drivers drove at shorter headways than after they received the information. The effect of the feedback was to reduce the time spent in short headways by approximately 25% and to increase the time spent in safer longer headways by approximately 20%. The effect was similar for younger and older drivers, for male and female drivers, for urban and highway speeds, and for daytime and nighttime driving. (Author/publisher)
Abstract