Samenvatting
The report contains an analysis of the impact of the 55 MPH NMSL and the 55 MPH Enforcement Program in Massachusetts from 1973-1979. Monthly fatal and injury accident data from 1970-1979 were used in the Box-Jenkins Time Series approach to estimate the number of fatal and injury accidents forestalled on 55 MPH highways. The time series approach relates changes in monthly accidents to the implementation of the NMSL and the Enforcement Program. A significant reduction in fatal accidents was found for the Enforcement Program on Massachusetts Interstate highways. Significant reductions in fatal and injury accidents were found for the NMSL on Interstate and Federal-Aid Primary highways.