The project scope of work included the deployment of SCATS adaptive signal control hardware and software, TSP equipment, and presence detection (inductive loops and video detection cameras) at 18 intersections. In addition, new traffic signal controller cabinets, traffic signal heads, pedestrian signals, and pedestrian accommodations meeting ADA (Americans with Disabilities Act) standards were installed as needed.
Prior to the upgrade project, SCATS software was installed on a central server and made operational at the Cobb County TCC (Traffic Control Center). The City of Marietta and the City of Atlanta used regional computers to communicate with the Cobb County server and coordinate cross-jurisdictional control of adjacent traffic signals. TSP was enabled by modifying existing hardware and software used for emergency vehicle priority systems. In the City of Atlanta and Cobb County, additional upgrades were required at 15 intersections where two TSP detectors and a phase selector were installed at each intersection. All 60 CCT (Cobb Community Transit) buses were equipped with TSP emitters.
The following lessons were identified during the design and implementation process.
Identify functional boundaries and needs for cross jurisdictional control required to implement SCATS and TSP. During the planning phase each jurisdiction must agree on the control scheme and identify needs for cross-jurisdictional control at interconnected intersections.
Ensure that adequate infrastructure exists to support communications between the project intersections and the respective traffic control centers. It is important that each jurisdiction has field personnel involved who have a good understanding of the communications required to ensure the system is functional once complete. During the Atlanta Smart Corridor project, it was found that SCATS could use the existing fiber optic media installed for signal control, however, SCATS would need to operate on a separate channel. Depending on the type of existing signal systems, implementation of SCATS may require additional splicing and installation of dedicated fiber. SCATS and ACTRA signal systems, for example, cannot run on the same fiber.
Ensure control cabinets will be large enough to accommodate SCATS detection equipment. Type 336 cabinets do not have enough space for SCATS detector equipment and NEMA (National Electrical Manufacturers Association) cabinets cannot support the level of detection needed. Type 332 cabinets are best for intersections that require SCATS.
Identify back-up personnel for key project responsibilities. Multi-year projects should expect iterative staff changes as a course of business. A secondary representative should be identified for each key project position. Back-up personnel should be aware of the roles and responsibilities, and oversight needed to prevent certain aspects of the project from being overlooked or assumed completed by others.
The project evaluation report indicated that SCATS was successfully implemented and TSP was an effective low-cost improvement to bus operations. Evaluation results indicated the system improved mobility, reduced delay, and resulted in significant productively benefits for corridor travelers.
(Our website has many links to other organizations. While we offer these electronic linkages for your convenience in accessing transportation-related information, please be aware that when you exit our website, the privacy and accessibility policies stated on our website may not be the same as that on other websites.)