Abstract
United States Route 395 is being evaluated by the Lassen County Transportation Commission (LCTC) for roadway improvements. The focus area for improvements begins north of the junction of SR 70 to the junction of Route 36 west, just south of Susanville. Initial studies assessed the feasibility of upgrading the corridor from a two-lane rural highway to a four-lane expressway. Due to the scale and cost of the proposed upgrade, the objective of this project is to evaluate the potential safety performance of alternative improvements. An alternative identified is the addition of passing lanes and shoulder widening to 11 segments within the corridor. The analysis performed for each of the 11 segments provided insight into the effectiveness of the improvements in terms of collision reduction. Data available from a prior study for the corridor was used to investigate the safety performance of the project. Analysis for the project utilized observed collision frequencies from 2013 to 2018, safety performance function for a two-lane rural highway, the Empirical Bayes Method, and estimated collision frequency. Through guidance from the Highway Safety Manual (HSM), Caltrans literature, and Federal Highway Administration (FHWA) publications, the safety performance for a build and no-build scenario was assessed. The analysis estimates a total reduction in 42.95 collisions for a 10-year period after improvements are applied. The results of the safety performance analysis were considered along with the costs of improvements to support continued efforts in improving US 395.