This paper describes the planning and preliminary design of passing lanes in difficult terrain in Southern California. The paper is based on an investigation of approximately 350 miles of two-lane highways in Imperial, San Diego and Riverside counties for the California Department of Transportation District 11. The need for passing opportunities has arisen for several reasons, the most important being the fact that long section of highways are marked as no passing zones leading to extensive delays, driver frustration and increased accidents. Opportunities to pass are exacerbated by increasing volumes and mix of fast and slow moving vehicles (such as trucks and recreational vehicles), resulting in long platoons. Passing lanes are a cost effective solution to improve level of service and enhance safety on two-lane highways. (A)
Abstract