Utah Department of Transportation (UDOT) implements dynamic management of portable variable speed limit (PVSL) technology to reduce regulatory speed limits through an active work space.
The Utah Department of Transportation (UDOT) was selected as a recipient of FHWA’s Accelerated Innovation Deployment (AID) Demonstration grant to fund the use of a portable variable speed limit (PVSL) system on four roadway construction projects along I-15 and I-80, with a focus to:
- Encourage significant driver speed reductions within active work spaces where construction personnel are on site
- Adjust speed limits automatically in accordance with speed harmonization principles
- Minimize the length of the active work spaces for which the significant speed reductions are applied to encourage driver compliance with the speed limit
- Increase regulatory speed limits when workers are not present
- Provide a portable system that is easy for construction personnel to use.
This PVSL system used a dynamic variable speed limit (VSL) algorithm to raise and lower the regulatory speed limits. The PVSL system also provided a queue warning algorithm that operated independent of the VSL algorithm to control messages posted on the portable variable message sign (PVMS) trailers to disseminate dynamic information to drivers.
- A vendor was selected and awarded a contract covering the four deployment projects for 30 days each. Equipment rental cost for the PVSL system was between $173 and $329 per day, depending on the deployment scenario. The queue warning system was an additional $194 per day.
- In addition to the cost of renting the equipment, system deployment budgets are required to address equipment mobilization, training, and software configuration. It was determined that a 0.5 full-time equivalent of a field person’s time is needed to ensure the system transitions in parallel with construction activities and the AWS.
Equipment rental cost for portable variable speed limit system: $173 - $329 (per day)