To: Lane3 who wrote (8964 ) 3/16/2001 10:05:45 PM From: Gordon A. Langston Respond to of 82486 7.4 Motor-vehicle manufacturing regulations A major package of legislative regulation concerning the "safe" design of new passenger vehicles to be sold in the USA came into effect in 1966. This included the obligatory installation of seatbelts for all vehicle seats, a steering column that would collapse in a crash instead of piercing the driver's chest, penetration-resistant windshields, a dual braking system, and padded dashboards. The effect of these mandatory construction features upon subsequent accidents was studied by an economist at the University of Chicago.[15] Comparing the pre-regulation period 1947-1965 with the 1966-1972 period, in which there were more and more regulated vehicles in use, he came to the conclusion that the newly-legislated vehicle-manufacturing standards had not led to a reduction in the number of fatalities per km driven. While the legislation may have brought about a reduction in fatal accidents to car occupants per km of mobility, it did not reduce the total death rate so defined. It may, in fact, have led to an increase in the death rate of non-occupants, such as bicyclists and pedestrians, per motor-vehicle distance of mobility. A similar shift in risk from drivers to pedestrians has been reported in Australia.[16] The Chicago study was published in 1975, and has been attacked ever since by many other authors who maintained that the vehicle-manufacturing standards have had a reducing effect upon the traffic death rate per unit distance driven by motor vehicles. There have been others who found evidence supporting the controversial findings.[17] In fact, in 1989, the issue was still not settled.[18] You may already have concluded, and correctly so, that this debate is, at best, only marginally relevant to the question of the validity of risk homeostasis theory. There is nothing in that theory that says that the accident rate per km driven cannot be reduced by technological interventions, regardless of whether they are mandated or not. What we are interested in is the accident rate per hour of exposure to the roads and per head of population. As regards the post-regulatory years 1966-1972, one definitely cannot detect in Figure 5.5 a lower per capita traffic death rate than in the preceding years 1947-1956. On the contrary, it was noticeably higher. What you can see in Figure 5.5 is that the increase in the traffic death rate per capita from 1961 to 1965 did not continue between 1966 and 1972. Was this due to the vehicle-manufacturing standards that came into effect in 1966? This would seem rather unlikely. Note that the period 1966-1972 falls within the 1960-1982 time frame that has shown a high correlation between the rate of employment and traffic fatalities, as was discussed in Section 5.4. That correlation was very high and leaves little room for anything else that may have exerted an independent influence. The effect of the 1966 legislation on the per capita death rate in traffic, if it occurred at all, must have been quite marginal. [PREVIOUS CHAPTER] [NEXT CHAPTER] Copyright © 1994 Gerald J. S. Wilde, Ph.D. since FEB-10-96. pavlov.psyc.queensu.ca