The extent of the 1982 traffic accident casualty reduction in British Columbia has been evaluated and found to be beyond what could be expected from chance fluctuation alone. The greatest changes were found in casualty-producing accidents involving young drivers, especially during the nighttime. These accidents were seemingly independent of alcohol use. Given this initial determination, the possible external causes for the decrease have been examined with the result that economic factors alone can be shown to account for a large part of the effect, although for a significant portion of the change, there is as yet no ready explanation. The most important conclusion arising from the analysis is that should economic conditions improve, a concomitant rise in traffic casualties can be expected unless mitigated by significant safety program interventions.