Abstract:
The first edition of the Highway Safety Manual (HSM) provides a quantitative
approach to predict the safety of transportation facilities based on the recently
developed scientific methods. This approach, known as the predictive method, was
developed for several states in the United States. Due to differences in driver
population, weather condition and other issues, the State of Oregon is expected to
calibrate these predictive models before using them. By locality, the existing
predictive methods can be divided into two parts: rural highway predictive method and
urban highway predictive method. This thesis focuses on the calibration project for the
rural predictive models. Therefore, in the first part of this thesis, the author will
illustrate the calibration process and calibration results for the rural facility types,
including rural two-lane, two-way roads and rural multilane highways. Also, after the
calibration project, the author found a new calibration sample size estimation
procedure which is more statistically reliable than the current HSM sample size
determination process. This new statistical estimation method will be explained and
recommended for future calibration projects.
