STC and TCC safety project for MODOT
TEMPE, 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
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
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