This document explores a methodology designed to predict the safety performance of various elements considered in the planning, design, and operation of nonlimited-access rural multilane highways. Chapter I provides an introduction, covering the background and the research objectives and scope of this project. Chapter II documents the literature review on existing statistical models, Accident Modification Factors (AMFs), and other predictive methodologies relevant to this study. Chapter III summarizes the results of a survey conducted in this study. Chapter IV describes the characteristics of the data collected in this project. Chapter V describes the model development and accident prediction methodology. Chapter VI summarizes the modeling results for estimating the safety performance of rural multilane highways. Chapter VII provides a summary of the work accomplished in this project and proposes recommendations for further work. The appendices document additional models from related research for consideration, Highway Safety Manual Chapter 9, the survey instrument, Cumulative Residuals (CURE plots), crash severity models, a methodology for estimating the variance of the product between baseline models and AMFs, and the Joint NCHRP 17-25/17-29 Expert Panel assessment.