RES 95024X - Laserfiche WebLink

Recommended Improvement Plan ' merits m the gateways serving Tri-Valley are financially infeasible. The Policy of the Tri-Valley Transportation Council is to work closely with neighboring jurisdictions, Congestion Management Agencies, Caltrans, and MTC to resolve capacity problems at the gateways and as needed through the partnership activities and to subsequently adjust our Transportation Plan should funding of mutual acc~:ntable facilities become possible. Freeway Ramp Metering. R~mp metering is a way of controlling the volume of traffic entering a freeway so the system is as efficient as possible. A survey made for the Federal Highway Administration of seven ramp metering systems in the United States and Canada revealed that aver~ :,:~ highway speeds increased by 29 percent after installing r~mp metering and travel times decreased 16.5 percent. At the same time reductions of freeway congestion averaged approximately 60 percent. An analysis of the FLOW system in Seattle (r~mp metering and HOV lanes) revealed that in addition to similar improvements in speed and travel time, highway throughput increased from 12 to 40 percent as a result of ramp metering. An additional bonefit from r~mp mete~ng is a decrease in the accident rate. Reductions from 20 to 58 percent have been achieved through improved merging operations. Without r~mp metering, bottlenecks will develop on the freeway that decrease throughput and lead to longer delays than motorists face at the meters themselves. Ramp meters also encourage the peak spreading that needs to occur t~ !<eep the gateways flowing. This happens because motorists are willing to accept only up to about a 10-minute wait at the meters. Beyond that, they will adjust their trip-making (i.e., choose to travel at a different time or choose a different mode). This peak spreading helps to get the most out of the system when gateway constraints are a reality. Without ramp metering it is projected that the freeway flow will break down and be congested for long pe:iods of time with the on-romps not being able to flow at their designed flow rates. ~ ne on-ramps will be metered by freeway congestion rather than planned rates. Staff believes a metered system will move more people more effectively and equitably than an unmanaged system. The unmetered system is also more prone to be blocked by congestion-induced accidents than a metered system. An additional major benefit of r-rap metering is that it can be com~med with HOV bypass to provide an additional ~:,owerful incentive for carpooling and can help buses increase average speeds. When . imbined with HOV lanes on the freeways, the romp metering-with-bypass system ahows carpools and buses to travel unimpeded through- out the system. Ramp metering has two potential drawbacks: backups on the local street system, and rewarding long-distance commuters. The potential for backups on local streets car: be minimized throu~' :~mp widening and strategic placement of the meters. The risk of rewardnng long-di~; ~ance commutes can be minimized by instituting a system of romp metering for the entire length of a freeway, rather than in isolated locations. Barton-Aschman Associates, Inc. 125 '