A safety expert from the Iowa Department of Transportation is warning motorists to be on the lookout for farm vehicles.They’re part of what drives Iowa’s economy, but combines and tractors pulling wagons move at a slow and steady pace. D-O-T safety specialist Scott Falb says accidents happen when the slow vehicles share the roadways with people who’re in a hurry. He says the harvest season combined with an early sundown makes it harder to see slow moving vehicles.Falb says drivers don’t realize the difference in speed between their cars and farm vehicles.Most slow-moving vehicles travel at speeds of 25 miles-an-hour, while many rural roads have speeds of 55-miles-an-hour. He says farmers need to be on the lookout too as most accidents occur when vehicles are making a left turn. He says farmers can be proactive in preventing accidents.Farmers should pull off to the side when there are long lines of traffic behind them and it is safe to get out of the way. Falb says quickly spotting the vehicles and slowing down is the best way to avoid a crash.