Roadway intersections are fascinating things. At the core, they are the connecting piece between two byways where you find two similar, but competing interests at play—the right to pass through and the desire for minimal disruption to travel. These competing interests create opportunity for crashes when one person assumes, or sometimes simply takes, the authorization to move through the intersection ahead of the other. In short, roadway intersections are subject to human fallibility.
Over the past century, we have created many types of systems to regulate intersections, yet crashes still occur. Human fallibility persists.
According to the Federal Highway Administration (FHWA), 40% of all crashes and 21% of all fatalities are related to intersection incidents. In Arizona, on average there is a vehicle collision every four minutes. But where there is a problem, you will likely find an engineer or a team of engineers and researchers hard at work to solve it. This is where we began in Maricopa County in 2007.