Iowa Department of Transportation (DOT) officials say the traveling public may notice a new addition to the landscape along Interstate 35/80 in Des Moines near the N.W. Beaver Road overpass. Two new technologies are now working in unison to collect highway data necessary for Iowa DOT decision makers. A wind turbine powering state-of-the-art laser sensors allows for safe, continuous data collection.
Implemented on I-35/80 in September 2008, the data collection technology uses the AxelLight laser sensor, which allows the Iowa DOT to perform challenging traffic studies without cutting into the pavement or needing to cross or venture onto a hazardous roadway to install traffic sensors in the pavement. This is the country's first permanent installation of this technology.
The installation on I-35/80 uses two sensors with parallel beams 6 feet apart that allow traffic data collection and complex vehicle classification in up to four lanes.
Another national first for this data collection unit is the way it is powered. A 20-foot wind turbine was installed in mid-February with a rotor diameter of 46 inches to power the AxelLight laser sensor. Of the Iowa DOT's 160 traditional, non-laser permanent highway data collection sites around the state, 158 are powered by solar panels. The remaining two use AC power sources. According to Iowa DOT, the new AxelLight laser site on I-35/80 was not conducive to solar power due to limited exposure to the sun's rays.
Data collected at the Iowa DOT's permanent sites and nearly 12,000 manual counts conducted each year are used to evaluate future roadway needs, conduct traffic studies, provide information to the public and decision makers, and for many other applications.