RURAL ROADS SPEED INCONSISTENCIES DESIGN METHODS. PART 1. OPERATING SPEEDS AND ACCIDENT RATES ON TWO-LANE RURAL HIGHWAY CURVED SECTIONS: INVESTIGATIONS ABOUT CONSISTENCY AND INCONSISTENCY IN HORIZONTAL ALIGNMENT

The document contains reviews of international speed concepts and accident characteristics in different countries, a methodology for use in the analysis of speed and accident data, an analysis of variables affecting oprating speeds and accident rates with the corresponding prediction equations, and investigations about reasonable boundaries for good, fair, and poor design practices. The research was undertaken to determine by regression analysis the influence of design parameters and traffic volume on operating speeds and accident rates, as related to an established data base of 261 road sections of two-lane rural State Routes in the State of New York. Of the several parameters considered, the most successful parameters for explaining much of the variability in operating speeds and accident rates were found to be degree of curve or posted recommended speed.