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

ENTERPRISE Transportation Pooled Fund Study

Variable Speed Limit (VSL)

For purposes of the ITS device guidance process, VSL shall mean a sign capable of displaying different speed limits to travelers (in which the speed limit is either a recommended or mandatory limit) that are either manually activated or controlled by a combination of detectors and algorithms to select appropriate speeds.

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.

Four (4) guidelines have been identified to capture the most common uses of VSL. While there are other purposes and uses for VSL, the guidelines developed to date have focused on the following four. If you have a suggestion of additional VSL guidelines please contact us.

VSL Guideline - 1:

Maximize Capacity

VSL Guideline - 2:

Safe Stopping Distances

VSL Guideline - 3:

Safe Travel Speeds for Conditions

VSL Guideline - 4:

Work Zones