STC In The News

STC and TCC safety project for MODOT

Sensor Activated Flashing Beacon Systems - Solar Traffic ControlsTEMPE, AZ - 05/03/2013 - Missouri DOT (MODOT) is working to improve safety for motorists along Highway 50 near Lee's Summit, MO. The route consists of two lanes westbound, two eastbound with a large median between them (about 3-4 lanes wide).

Highway 50 has posted speed limits of 65mph just east of town; several side roads allow local traffic access. Previously, the intersections did not feature any signals but have now been outfitted with warning beacons. The beacons are placed so they warn traffic on the side roads of higher speed traffic approaching. Each side road access point has an advance detection station and a flashing beacon. Traffic Control Corporation and Solar Traffic Controls teamed up with a MODOT engineering team led by Dave MacDonald (RET), to create a solution for the project.

Using RTMS and STC Flashing Beacons
Located in advance of each side road is an RTMS ( sensor which employs side-fired radar to detect vehicles passing the detection point. Once a detection occurs, the sensor station control logic locks it in as a call and radios a run time value to the flashing beacon control logic which starts the warning beacons flashing. There were four detector locations; three of the four did not have access to AC power.

The fourth location did have AC power but was about 600 feet away across an open field. The solar-powered detection points included a self-contained solar power system designed to power the equipment year round based on the solar data for the location, the equipment load and the projected duty cycle for all the equipment. A user interface allows the setting of the run time for each road's flashing beacon as the distances from detector to flashing beacon varied at each of the four locations. Each detection station also included a self-test function to allow DOT personnel to test the equipment without the sensor present.

With the availability of AC at one detection point, STC designed an AC equivalent to the solar-powered detection stations. The two systems function similarly except for the incoming power source.

There is an associated flashing beacon for each detection station. Three of the four flashing beacons are solar-powered; the fourth is AC-powered from a nearby service point. All the solar-powered beacons use the STC 12-inch amber DC lamp which has an optical output greater than 990 Cd on center (ITE is 910) to ensure an adequate optical output. Both flashing beacon stations and the detector stations use a modified version of the STC Solar Ped-X control package which includes a 1W FHSS radio link.

Please note: This project was started to minimize the incidence of accidents from traffic entering the highway from side roads. An accident in the recent past led to a need to address the issue. By warning drivers on the side roads of the approaching high speed traffic via the flashers it is hoped fewer accidents will occur. For more information please contact Ken Kohl at the TCC St. Louis area office via the company's main website at

Celebrating our 12th year designing and manufacturing solar-powered traffic control systems. For more information on STC's products and services, please stay here on our website or send an email to or call 480.449.0222.


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