Settled in 1799, Hudson, Ohio, is a thriving city of 23,000 that has managed to preserve its historical feel. But modern state highways bisecting the community's historic downtown area have created unique traffic problems.

“Traffic backs up significantly during peak hours,” says Chris Papp, project manager with Hudson's Department of Engineering. And because trust-protected lands reside in the city center, “through lanes can't be added to widen the highways even if the city wanted to.”

An over-capacity intersection also means congestion can impede emergency services. This is a serious problem, since Hudson's Fire Department and Emergency Medical Services (EMS) is located less than a quarter mile from downtown intersections. The city needed a way to clear traffic when emergency vehicles respond to calls.

When fire chief Bob Carter came to Hudson, he suggested using a 3M Opticom infrared (IR) intersection priority control system to provide right of way to emergency vehicles. With this system, emergency vehicles can request and receive green lights by transmitting IR signals from emitters on the vehicles to receiving detectors at intersections. But Hudson's streets have many hills and turns that would get in the way of line of sight. Plus, two railroad viaducts in critical locations would block IR signals to intersections beyond the viaducts.

3M had another idea.

The St. Paul, Minn.-based company had recently introduced its 3M Opticom global positioning system (GPS) intersection priority system. Because the system uses satellite-based radio navigation, line of sight is not needed. The GPS allows the system to transmit location, heading, speed priority, and turn signal status of an approaching vehicle—regardless of obstacles. It also determines time of arrival.

The Opticom GPS initiates an all-red phase and a green light in the direction of travel only at the request of the vehicle. The green light is initiated far enough in advance to clear out traffic in front of the emergency vehicle. As a result, heavily congested intersections without direct lines of sight are cleared to allow for safer and faster responses by emergency vehicles.

The next issue was funding. With 3M's assistance, Hudson obtained an Assistance to Firefighters Grant administered by the Department of Homeland Security. The grant paid for 90% of the system's costs, and Hudson paid the remaining balance with local tax revenues. The total project cost was approximately $225,000, exclusive of administrative costs.

The community equipped its 23 signaled intersections and all its fire and EMS vehicles, including staff cars, with Opticom GPS. And Hudson's police vehicles may also be equipped in the future.

— Lorin R. Robinson is public relations manager with 3M Center, St. Paul, Minn.