RECAPTURING CAPACITY BY REMOVING FREEWAY BOTTLENECKS (ABRIDGMENT)

Congestion on urban freeways affects safety, air quality, energy consumption, and motorist delay. In areas where travel demand far exceeds capacity, some level of congestion is inevitable. However, when imbalances in the freeway system exist, bottlenecks restrict the use of available capacity. If these bottlenecks are removed, valuable capacity can be recaptured, congestion reduced, and impacts diminished. Detection of bottleneck locations requires knowledge of traffic volumes and travel speeds and observations of traffic patterns and driver behavior. Bottleneck relief can be found in many cases by restriping lanes, by modifying weaving areas, or by converting some shoulders to driving lanes. Implementation of low-cost improvements, even on an interim basis before permanent improvements, can have an excellent result. Because removal of congestion on one segment of the freeway system may move congestion and impacts to other segments, consideration must also be given to the system implications. In addition, issues such as state and federal policies, public acceptance, and funding for any improvement must be addressed before implementation. However, if these obstacles can be cleared, low-cost improvements to remove bottlenecks will provide significant benefits. In a time of fiscal constraints and with public attention focused on urban congestion, every attempt must be made to get the most efficiency out of our existing freeway systems.