Methodology for estimating the variance and confidence intervals for the estimate of the product of baseline models and AMFs

This manuscript describes a methodology for estimating the variance and 95% confidence intervals (CI) for the estimate of the product between baseline models and Accident Modification Factors (AMFs). This methodology is provided for the upcoming Highway Safety Manual (HSM) currently in development in the United States (U.S.). The methodology is separated into two parts. The first part covers the proposed approach for estimating the variance of the estimate of the product between baseline models and AMFs. The second part presents the method for estimating the variance of baseline models. Several examples are presented to illustrate the application of the methodology.