The Iowa Department of Transportation is using a mix of new and old technology to count traffic in a busy area along Interstate 80-35 in Des Moines. D.O.T. spokesperson Karen Carroll says the high-tech laser system counts the vehicles.
Carroll says the system puts two lasers across the road and counts traffic as the vehicles cross the lasers. She says they decided on this system because it would be costly to have to shut down and tear up the road to install the traditional loops under the roadway that measure traffic. Caroll says its’ called the " AxleLight " laser system and is able to tell the type of vehicle by the number of wheels and the distance between each wheel.
Carroll says the system does all the calculations for them and they can access the information at the D.O.T. in Ames from a cell modem. Carroll says the laser system has been used for temporary traffic counts, but this is believe to be the first permanent used of the system in the country.
She says the traffic studies are important to the D.O.T.. Carroll says the data is used for a variety of things, including mandate reporting to federal officials for use in determining funding that comes to the state. Carroll says the information is also used in designing and planning roadways. While the laser system is state-of-the art, Carroll says they had to turn to an old method to power the system.
Most of the D.O.T.’s monitoring stations in the state are powered by solar cells, but this location was too shady, and they decided to install a wind turbine to create the needed power. Carroll says the turbine is approximately 46 inches in diameter, which is much smaller than the massive wind turbines going up to produce large amounts of electricity. She says this turbine produces enough power to run the laser system and is working very well so far.
Carroll says motorists driving along the Northwest Beaver Road overpass in Des Moines won’t notice the laser beams across the road and likely won’t notice the wind turbine either.