Abstract
The impact of metrication of highway speed and distance signs incanada was evaluated using concealed roadside radar on four different road types. Vehicles were classified into commercial and passenger categories. On the day following metrication there was a decrease in mean speed of all vehicles (n . 2424) Of about 1.9 Km/h and an increase in speed variability by an average of 28% compared with premetrication norms (n . 9413). Follow-up surveys indicated that within 2 weeks following metrication, drivers had returned to premetrication velocities for all sites surveyed.(A)