This paper contains a description of a process for identifying sections of rural New Mexico Interstate, primary, and secondary highways with significant fixed-object accident experience. Data bases for the analysis are the computerized accident record and roadway inventory systems for the 3-fiscal-year period from 1980 to 1982. The rate quality control method is used as the statistical technique to identify those sections of roadway that are most in need of examination. Accident and inventory information are combined to calculate critical accident rates for sections of roadway on each of the three systems. Calculated critical rates are then compared with the actual rates on each section, and a listing of sections arranged by criticality (the difference between the actual and critical rates) is obtained. This listing is used by New Mexico State Highway Department personnel to prioritize locations for implementing safety improvements" The procedure is applicable to the analysis of other subsets of accidents as well. Data quality is critical for the proper application of the technique; factors other than accident experience, in addition, must be considered in the cost-effective development of accident reduction countermeasures.

National statistics<!.> indicate that over 63 percent of fatal traffic accidents involve only a single vehicle. Even when pedestrian and pedalcycle accidents are excluded, single-vehicle accidents still account for over one-half of all traffic fatalities. The most frequently cited" first harmful event" for single-vehicle fatal accidents on a national level is collision with a fixed object (48 percent of all single-vehicle fatalities), followed by collisions with pedestrians and pedalcyclists (29 percent) and overturning accidents (17 percent). Rural highways, which account for 44 percent of the nationwide total vehicle miles of travel (VMT), account for 56 percent of the single-vehicle fatal accidents. Despite the emphasis on clear roadsides for Interstate high-ways, occupant fatalities in single-vehicle accidents remain the largest component of the fatality toll on these facilities.