Fog Detection, Traveler information and Dynamic Traffic Control System

Orth-Rodgers & Associates, Inc. (ORA), has completed a design-build project of a 10-mile ITS network for the Pennsylvania Turnpike Commission which includes 10 dynamic message signs (DMS), 25 variable speed limit signs (VSLS), and 9 road weather information systems (RWIS). Responsibilities included project oversight of all facets including design of hybrid communication network including both fiber optic cable and spread spectrum radio, field device selection and location, development of a PS&E package, bidding and contractor selection and contract negotiation, construction management and inspection services, as well as participating in the software development.

By utilizing the RWIS data, specifically from the visibility sensors, the system monitors visibility conditions triggering system esponses when a visibility threshold is crossed. With a change in visibility, the system notifies the traffic operations center (TOC) of the change and automatically responds with a strategy of appropriate messages for the DMS and speed limits for the VSLS based on those conditions. The TOC operator has both speed data and camera images to use as a verification tool to override the automatic response, should the operator choose to do so. The TOC can control both the DMS and VSLS independent of the Fog Detection System for use in incidents or maintenance activities. ORA was the prime contractor for this $5.7M design-build project. The system was activated in November 2005.