The Iowa Department of Transportation switched on four new overhead message boards Wednesday above interstate traffic in the Des Moines area. D-O-T area maintenance manager Lance Starbuck says the lighted, changeable signs will let motorists know when foul weather could be causing trouble ahead. He says they’ll give messages about pavement temperature, winter driving conditions and tells when snow removal equipment is being used.While they’re common in big cities, Starbuck says these are the first signs of their type to be used on Iowa roads for weather warnings. He says this pilot project could be expanded statewide, depending on how motorists react to the service. Starbuck says the signs can be easily changed, depending on weather conditions.The signs can be programmed from the office or from home by a D-O-T supervisor after hours. The Highway Patrol will also be able to access them. Iowa D-O-T spokeswoman Dena Gray-Fisher hopes motorists who see the signs on Interstates 35, 80 and 235 around Des Moines will make comments about them.The four signs cost 153-thousand dollars each. Gray-Fisher says signs above interstates elsewhere in Iowa are being used to notify motorists of other potential hazards but -not- weather data.