Population growth in the past two decades in Maricopa County has sparked a roadway construction boom in Phoenix and neighboring municipalities. But despite extensions of roads and highways and additions of more lanes, jampacked roads continue to be the norm. It’s not surprising, says Steve Polzin, a Fulton Schools professor of civil engineering and a former senior adviser to the U.S. Department of Transportation. The problem isn’t only a result of people driving more but of more people driving, he says. That echoes comments of the Maricopa Association of Governments transportation data program manager, who says every growing metro area in the U.S. is experiencing increasing traffic, even as they continue to add lanes to highways and major streets.