Monthly Archives: July 2012

Image credit: Wall Street Journal

by James A. Bacon

Computer-operated vehicles are coming, and they offer the potential to create dramatically safer, less congested roads, asserts Clifford Winston, a Brookings Institution scholar writing in the Wall Street Journal today. “The driverless car represents one of the most amazing breakthroughs in safety and quality of life in recent history.”

The greatest barrier to reaping phenomenal benefits in mobility, suggests Winston, is not the automobile manufacturers, “who have made one technological improvement after another since the car was introduced to consumers more than a century ago,” but the ability of roads, streets and highways to accommodate the new generation of super car.

“Unfortunately, the paved systems on which cars travel have not advanced much in comparison,” he writes. “Without reimagining the way we design and maintain highways, the driverless car will achieve little of its potential.”

With current technology, driverless cars are operated by computer that obtain information on surrounding cars 10 times per second from short-range transmitters, allowing them to respond exponentially faster than human drivers can to changing conditions. The technology will drastically reduce accidents caused by human error, and it will reduce delays by creating smoother traffic flow and rerouting drivers away from congestion.

The technology can vastly expand the capacity of existing roads. Writes Winston:

Driverless cars don’t need the same wide lanes, which would allow highway authorities to reconfigure roads to allow travel speeds to be raised during peak travel periods. All that is needed would be illuminated lane dividers that can increase the number of lanes available. Driverless cars could take advantage of the extra lane capacity to reduce congestion and delays. …

The smaller volume of trucks could be handled with one or two wide lanes with a road surface about a foot thick, to withstand trucks’ weight and axle pressure. But the much larger volume of cars — which apply much less axle pressure that damages pavement — need more and narrower lanes that are only a few inches thick. Building highways that separate cars and trucks by directing them to lanes with the appropriate thickness would save taxpayers a bundle.

While highways need to be reconfigured, streets and roads would need to become smarter. “On local streets, signal timing contributes to hundreds of millions of vehicle hours of annual delay because it is based on out-of-date historical data that inaccurately measure relative traffic volumes at intersections. Without signals based on real-time traffic flows, driverless vehicles may not be able to accurately align their speeds with them.”

Winston foresees using electronic tolls to charge motorists for their contribution to congestion and to motivate them to travel during off-peak periods, use alternate routes or shift to public transit. Artificial intelligence in driveless cars could balance the cost of tolls with travel time savings to optimize motorists’ route choices.

Bacon’s spin: OK, that’s all very exciting. Let’s assume for a moment that these technological marvels really are coming. (Given the extraordinary gains in affordability of computer chips, sensors and wireless technology, I don’t doubt it for a moment.) What do we do about it?

If roads and highways are the limiting factor, not automobiles, then state policies will drive the transition to the better world that Winston envisions. That creates an opportunity for states, such as Virginia, that might want to take the lead in addressing their intractable safety and congestion problems. But making the kind of changes that Winston discusses will take a drastic change in culture and skill sets at the Virginia Department of Transportation.

I would argue that Virginia has woefully under-invested in traffic signalling technology. In the one instance with which I am familiar, it has worked spectacularly successfully on U.S. 29 north of Charlottesville, reducing congestion to the point that there is no longer any justification for building a roughly $240 million bypass. Rather than learning from its success, the political system lumbers onward, pushing through the project in blind denial of the reality that congestion is much diminished. (Stop light synchronization has been applied in Northern Virginia as well, but I do not know how successful it has been.)

Right now, the big technological initiatives in Virginia highways focus on asphalt. One project is studying how novel asphalt mixtures can reduce noise. Another seeks to reduce costs by recycling asphalt in repaving jobs. Those are useful (and I have written about both). But the big strategic gains will come from building smart roads and highways that can interact with the next generation of smart cars.

VDOT needs to start building the skill sets that will allow the department to start thinking intelligently about smart roads. The states needs to begin experimenting more aggressively with smart sensors, signals and traffic algorithms. We need to think how we might transition from our current dumb highways to Winston’s radically redesigned highways without causing mayhem all the way, and how to do so within tight budgetary constraints. We also need to think about unforeseen complications — such as a blown tire that causes a wreck that cascades into a 100-car pile-up. And we need to examine the laws, regulations and policies arising from a century of asphalt-centric roads to see how they might be updated.

The automobile manufacturers will be ready long before state highway departments will be. Let’s ensure that Virginia is one of the first states to exploit the new possibilities.