Stop Sign Gap Assist Systems for Future Traffic Intersection Safety

MOHAVE COUNTY PUBLIC WORKS

Mohave County Installs Eleven Stop Sign Gap Assist Systems for Future Traffic Intersection Safety

In 2023, Mohave County was just one of eight nationwide recipients of federal Advanced Transportation Technology and Innovation (ATTAIN) program grant funds to deploy state-of-the-art technologies to improve traffic safety. The County received $1 million ATTAIN funding, and the County secured $200,000 in Arizona SMART funds that fulfilled the County’s federal grant match requirement.

The combined federal/state funding enabled Mohave County to install one of, if not the first Stop Sign Gap Assist (SSGA) systems in the United States at eleven highway intersections. Each system assembly consists of two video-based traffic detectors, a roadside unit (RSU), and a solar panel for system power on a single pole-mounted assembly.

The SSGA system functions when a camera detects the presence of an approaching vehicle on the intersection primary road. Then, the RSU wirelessly broadcasts on oncoming vehicle alert message to any vehicle equipped with an on-board unit (OBU) that is stopped at the intersection crossroad. Stopped drivers with an OSU equipped vehicle receive said alert message through in-vehicle dashboard or heads-up display.

This Project provides the most direct, real-time warning of conflicting high-speed traffic to drivers of properly equipped vehicles. The automotive industry is expected to incorporate OBUs into new vehicles in the not-too-distant future. The ATTAIN grant and Project is premised on advance installation of this roadside infrastructure ahead of the automotive industry rollout.  As part of this Project, the County will receive ten permanently installed OBUs for its vehicle fleet to facilitate pilot testing of the SSGA system.

Intersections with SSGA systems include: 

1. Pierce Ferry Road at Stockton Hill Road 
2. Pierce Ferry Road at Diamond Bar Road 
3. Shinarump Drive at Estrella Road 
4. Shinarump Dive at Colorado Road 
5. Shinarump Drive at Aztec Road 
6. Shinarump Drive at Oatman Highway 
7. Oatman Highway at Boundary Cone Road 
8. London Bridge Road at Retail Centre Boulevard 
9. London Bridge Road at Fathom Drive 
10. London Bridge Road at Chenoweth Drive 
11. SR 68 at Colorado Road