IDOT—Intelligent Transportation System

Military Maneuvers on the Poplar Street Bridge

The Poplar Street Bridge, linking Missouri and Illinois, crosses the Mississippi River just south of the St. Louis Arch. Many modes of transportation depend it. Several highways converge on the bridge, carrying commuters and tractor-trailers, while below seven major railroads use a web of tracks and yards.

To ensure safety and consistent traffic control, the Illinois Department of Transportation (IDOT) hired Wissehr to install a video vehicle detection system to complement its Intelligent Transportation System. The Intelligent Transportation System collects and analyzes information to improve overall traffic flow. The vehicle detection system consists of six cameras, which are located on the bridge and on the elevated approaches on the Illinois side. Using the system, traffic managers can count vehicles and sense traffic speed, starts and stops.

The demanding, dangerous project took Wissehr electricians from the swamps around the footings of the bridge to the farthest heights on its spine. To prepare for this challenge, managers put their military planning theory to work, finding staging areas, lining up radios and other specialty equipment, scheduling railroad flagmen, assessing traffic flow for lane shutdowns and devising contingency plans upon contingency plans. Communicating with many entities such as IDOT, seven railroads and Illinois State Police was a key factor.

After intense planning, the project went smoothly. Tom Wissehr, president, explains, “We used our own excavation services and installed underground 4500 lineal feet of three-inch conduit. We also attached 2700 feet of three-inch rigid conduit to the bridge structures, piers, parapets and beams. To reach the high camera locations, we used large aerial lifts to reach the 120 foot elevation on the main line structure.”

In addition, Wissehr installed 16,000 feet of multi-conductor communications and data cable from the six cameras back to six control cabinets, little substation enclosures that hold all the video and data equipment. Wissehr installed a T-1 line from each substation, connecting all of them to IDOT’s central office in Collinsville.

Drivers can also use the vehicle detection system. To check bridge traffic you leave on your trip or daily commute, visit IDOT’s website. And as you aproach the bridge and click on the cameras, smile...

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