Convertible Roadways and Lanes. A Synthesis of Highway Practice

摘要

The development of new roadways and the conversion of existing ones that can be adapted for different uses at different times of the day has been one method used by transportation agencies to more cost-effectively accommodate the constantly changing needs of highway travel. Convertible roadways encompass a variety of techniques that afford an agency an added measure of flexibility in how and when it responds to the needs for more on-street parking, additional intersection turning lane capacity, and short-term corridor capacity. Originally, the intent of this report was to synthesize information related to convertible lanes. However, owing to the lack of readily accessible information within that topic, the scope of the synthesis was narrowed to primarily cover reversible roadways and lanes, one of the largest and more well-documented subsets of convertible facilities. Reversible traffic operations are widely regarded as one of the most cost-effective methods to increase the capacity of an existing roadway. The principle of reversible roadways is to configure the lanes of a roadway to match available capacity to the traffic demand. These roadways are particularly effective because they take advantage of the unused capacity in the minor- flow direction lanes to increase the capacity in the major-flow direction, thereby eliminating the need to construct additional lanes. They are most effective when highly unbalanced directional flows are present, such as those that occur during daily peak-period travel times, before and after large events, and during emergency evacuations.