This study was intended to quantify the benefits and costs resulting from lane widening, shoulder widening, shoulder surfacing, sideslope flattening, and roadside improvements. Detailed traffic, accident, and roadway data were collected on 4,951 miles of two lane roads in seven states. An accident predictive model and statistical tests were used to determine expected accident reductions related to various geometric improvements. Construction cost data from several states were used to develop a cost model for numerous types of roadway and roadside projects. This volume contains the final report and four appendixes. The final report contains detailed information on data collection and data analysis and conclusions and recommendations. The appendixes contain detailed information on the literature review, photographs used for the rural and urban roadside hazard scales, and economic analysis inputs.

This guide presents information for estimating the costs and safety benefits which would be expected due to various improvements on specific sections of rural, two-lane roads. Such improvements covered in this guide include lane widening, shoulder widening, shoulder surfacing, sideslope flattening, and roadside improvements. This guide will be useful to those involved with the design of 3R-type projects, particularly for improvement projects which will be constructed on existing vertical and horizontal alignment and within the existing right-of-way. The accident relationships with roadway geometrics and cost data contained in this guide resulted from research conducted for the Federal Highway Administration. FHWA research report FHWA/RD-87/008 entitled "Safety Effects of Cross-Section Design for Two-Lane Roads, Volume I, Final Report" contains the major results and conclusions of the study. FHWA research report number FHWA/RD-87/009 subtitled "Volume II, Appendixes" contains details on the data base and the data analysis

"This study was intended to quantify the benefits and costs resulting from lane widening, shoulder widening, shoulder surfacing, sideslope flattening, and roadside improvements"--Abstract.