Analysis of Urban Freeway Operations and Modifications

摘要

This report includes three separate research efforts--one analysis of operational characteristics and two case studies of specific improvements. The first study was an analysis of the operation of auxiliary lanes under high volume conditions. A case study of a ramp reversal in Houston is presented next. The final portion of the report is a case study of a ramp pair in San Antonio that was grade-separated to eliminate a short, heavily-congested weaving section. Based on historical information, this study makes some fairly broad assumptions regarding operational effectiveness. While the grade separation is shown to be highly successful in reducing weaving accidents, the study indicates that accident reduction alone is not likely to produce sufficient savings to justify the construction cost and, therefore, operating, travel time and delay costs must be jointly considered.