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New I-90 speed limit signs
The Washington State Department of Transportation (WSDOT) and Sound Transit are introducing 14 electronic speed limit signs on westbound I-90 as part of a 2009 Two-Way Transit project.
The electronic reader-boards can change speed limit numbers as needed, as well as post traffic updates and weather warnings. Many of the neon glowing signs have already been erected along the I-90 corridor between I-405 and I-5.
In total, there will be 14 variable speed limit signs in seven different locations. The signs are expected to “increase safety, decrease collisions and keep traffic moving during construction on westbound I-90 by alerting drivers to reduce their speed when backups or collisions are on the road ahead,” according to the WSDOT Web site.
The electronic signs are operated by underground sensors that gather data and adjust the speed using algorithms. Drivers’ speeds are also monitored by personnel in the WSDOT traffic management center.
The new electronic signs are common on Washington roads, existing already at Snoqualmie Pass, on U.S. Highway 2 at Stevens Pass and in other locations.
For more information on the I-90 Two-Way Transit program, visit: www.wsdot.wa.gov.