CCTV | DMS | HAR | RWIS | VSL | Dynamic Speed Displays | Ramp Meters| Curve Warning Systems| Intelligent Work Zones | ICWS

Planning Guidance for the Installation and Use of Technology Devices for Transportation Operations and Maintenance

ENTERPRISE Transportation Pooled Fund Study

VSL Guideline 1 - Maximize Capacity

Purpose: To maximize capacity by maintaining uniform travel speeds that are optimal for the current volume of traffic, and prevent the system from becoming ‘unstable’ and reaching congested conditions.

Engineering judgment should be used to assess potential implications that may result from installation of VSL. This planning guidance does not mandate the use of VSL.

1. The typical peak hour volume of the freeway corridor exceeds 1,100 vphpl.

AND

2. The route segment has a history of reduced travel speeds of 40 mph or less for a least one hour on typical days (55 mph posted speed).

AND

3. There is a regularly occurring speed differential of at least 10 mph of travel speeds below the posted speeds between the upstream and downstream locations of the segment (e.g. a downstream bottleneck location has typical speeds that are slower than an upstream location). (1)

Reference:

1. MUTCD. 2009.