This report (volume I) describes the development of a computerized system to facilitate the prioritizing of roadside fixed object treatments. The system was developed for the traffic engineering branch of the North Carolina division of highways. Volume ii, under separate cover, is a user manual for the system. The system is designed to perform economic analyses of various fixed object improvements on an area wide (or roadway segment) basis, such as determining the effect of removing all trees within 30 feet of the edge of pavement on rural, two-lane, secondary roads in the piedmont area. Inputs to the economic analyses include: (1) a determination of the frequency and severity of the most affectable accidents for a given hazard/treatment combination, (2) the expected reductions in fatal, injury, and property damage only accidents associated with implementation of the treatment, and (3) initial costs, maintenance costs, and repair costs over the service life of each treatment. Through the economic analysis, the net discounted present value and benefit/cost ratio is computed for each candidate fixed object treatment, and a priority ranking is developed based on comparisons of net present value. Analyses were concerned with the following fixed object hazards: (1) utility poles (2) trees (3) exposed bridge rail ends (4) substandard bridge rail (5) bridge piers (underpasses) (6) rigid sign and luminaire supports (7) guardrail ends and (8) median-involved accidents.
Samenvatting