Imagine a big sporting event – say, the Broncos battle for the AFC championship or the USAF Falcons are playing for their conference title. Now imagine a miles-long parade of self-driving cars endlessly circling around the stadium, clogging up roads, and jamming up nearby residential neighborhoods because their human passengers don’t want to pay for parking. So, people program the cars to drive and drive for hours until the humans are ready to leave the game. And if these self-driving vehicles run on gasoline, they could pollute the air more than human-driven cars do now.

That kind of nightmare scenario could emerge unless cities and states adopt sensible rules of the road aimed specifically at steering the new technology so it helps reduce both traffic congestion and air pollution. Yes, self-driving cars could provide a great service to the disabled or elderly populations, but many other consumers will adopt the technology too – and without thoughtful policy the driverless cars may also worsen sprawl and congestion.The lingo in the transportation wonk world is that driverless cars could lead to a “heaven or a hell” scenario.

The bottom line: while self-driving cars – also known as autonomous vehicles or AVs – offer tremendous promise, they also need to be deployed correctly. We, the U.S. public, need to get the policies right or many transportation problems we face today could just get worse.

In fact, cities and states today can start implementing policies to ward off many potential traffic and air quality problems that could arise as self-driving cars (AVs) become more widely used, concluded a just-published report that I co-authored for the Southwest Energy Efficiency Project (SWEEP). Without thoughtful policy and direction, future transportation systems will continue to deliver personal convenience at the expense of system efficiency, with gasoline powered self-driving cars traveling “empty” miles around the block to avoid high parking fees and running errands while we’re at work to save time. Studies referenced in the report conclude that widespread deployment of AVs could reduce energy use and pollution by as much as 90 percent – or could increase it by over 100 percent.

SWEEP recommends that cities and states establish rules that:

If local and state governments adopt sensible rules of the road now, they can set an expectation from the start that AVs will be used in ways that make our air cleaner and our communities more livable. Our leaders shouldn’t wait until bad business models become entrenched because bad habits are hard to break.