STC In The News

TCC and STC project helps increase intersection safety for MODOT

TEMPE, AZ - 01/10/2013 - Missouri DOT (MODOT) recognized a problem intersection at Pink Hill Road and Missouri Hwy H in Oak Grove, MO. Driving northbound on Hwy H the roadway climbs from a low area up a hill to the intersection. Because of the grade of the hill, vehicles wishing to cross Hwy H or turn onto it from Pink Hill cannot see easily see the approaching cars on Hwy H thus creating a traffic hazard for motorists on both roads.

Previously the intersection had a continuous four-way flasher on a span wire across the intersection. While this provided a warning to motorists, it was not interactive. MODOT approached Traffic Control Corporation (TCC) regarding the design of a sensor based system for improving the beacon operation for vehicles crossing or turning from Pink Hill Rd as well as vehicles traveling northbound on Hwy H.

The location proved challenging in that there was AC power available at some points but not at all of the points where beacons were needed. STC worked with TCC, an Econolite distributor, and MODOT to come up with a solution for the intersection. The new configuration included a three point approach. The main control point is an AC powered point, serves as the system master, includes video detection and an AC flasher circuit for one direction of travel on Pink Hill. Nearby the second point is a solar powered slave flashing beacon facing the opposite direction of traffic on Pink Hill. The third point, located in advance on northbound Hwy H, is both a flashing beacon system and a detector station, is solar powered and serves as an intersection advance flasher.

TCC and MODOT chose to employ an Autoscope video detection system at the Pink Hill Rd stop bars to detect when traffic was present. STC furnished a custom AC powered master system for the intersection based on the Solar Ped-X control package normally used for crosswalks. The enclosure included a two-channel Autoscope video detection system, an Autoscope camera power/signal interface board and a color flat screen monitor as well as connection for AC power and distribution within the enclosure.

The STC equipment included a Solar Ped-X control circuit with a NEMA flasher module to drive a beacon at the intersection. When a vehicle is detected at either stop bar a call is input to the Solar Ped-X controls. When the control logic responds to the call, a run time value is transmitted to the intersection advance flasher to warn motorists heading northbound that vehicles are present at the Pink Hill crossing.

The intersection advance unit employs an RTMS G4 sensor to detect vehicles traveling northbound on Hwy H. When a detection occurs a pending call is generated in the local Solar Ped-X control and detected by the master unit at Pink Hill. When the call is serviced, the flashers at Pink Hill begin flashing to warn motorist of approaching vehicles on Hwy H. The Solar Ped-X system includes retriggerable timers so additional vehicle detections add to the run time value.

The Solar Ped-X control package allows for two-way communications between points via FHSS radio link. This combined with the solar power package allowed the system to be installed more affordably and more timely than an all AC system.

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