As school buses roll once again, an Iowa company that’s helped clear the air is looking to grow. Dave DeValois says Mirenco offers retrofit options that make diesel engines work cleaner and more efficiently. DeValois says the computerized system called DriverMax tackles the heavy soot that comes from diesel tailpipes.DriverMax electronically controls the flow of fuel into the engine to prevent that soot from forming, while current products mostly “trap” or filter the exhaust. The Five Seasons Transit system in Cedar Rapids is using DriverMax. Mirenco’s also partnered with the state to measure the emissions of five-thousand schoolbuses, in a program called BEEP — Bus Emissions Education Program. They use an opacity meter to measure light blocked by the tailpipe smoke, and report to the schools on buses that have been tested and which have problems they’ll want to correct. DeValois says they figure they’ve prevented seven TONS of soot from going into Iowa’s air with the schoolbus program. Another Mirenco product almost ready for market will combine GPS technology with a computerized memory of the bus’s route, for a kind of ultimate cruise control. They call it “look ahead” technology, since the computer records the engine’s speed along a route, and after you’ve been along the road once it’ll automatically slow you down when heading downhill or into a curve, a safety feature but also great for saving fuel. That “Econo-Cruise” technology’s been tested in cooperation with the federal transportation agency. Another Mirenco product, Programmable Speed Control, limits how fast drivers can go in a public vehicle like a school or transit bus, but also smoothes the rate of acceleration to improve fuel economy. Located in Radcliffe, Iowa, Mirenco is reaching worldwide markets since beginning to market its technology in 1997.