Self-driving cars could clear light rail’s troubles

Driverless cars may be the future of car safety. The technology could also replace light rail cars, the authors say.
Driverless cars may be the future of car safety. The technology could also replace light rail cars, the authors say. AP

The failure to come to an agreement with Duke University has profoundly discouraged many advocates for mass transit in Durham and Chapel Hill. Even if Duke issues can be worked out, escalating costs are almost inevitable.

In past columns published in The News & Observer, we have expressed our unease over the usefulness and economic feasibility of the original light rail project, which envisioned 500-passenger trains, with 45- ton carriages, traveling on a 19 mile route that would leave large portions of our community outside walking distance to a station. However, despite our criticisms of the details of this project, we have always been sympathetic to the goal of mass transit for all.

We think that a rethinking of the project’s technology could reduce costs, increase the population served, and meet Duke’ University concerns about interfering with its medical center. We propose that large, building-shaking trains be replaced with 6-9 passenger self-driving vehicles, propelled with plug-in technology (just like a Volt or Tesla automobile). Such vehicles would shake Duke medical buildings much less than an existing delivery truck, and the internal battery would not generate electro-magnetic interference. They would also have many other advantages.

These vehicles could take the proposed fixed guideway along congested 15-501, but could also go off the guideway to serve individual neighborhoods all over Durham and Orange Counties. While we may some day have fully self-driving vehicles, at least at first the self-driving transit would take fixed routes over existing streets, at an urban speed of 20-25 mph. This is possible even with current technology. These vehicles would much better serve the elderly and handicapped, who could not easily walk even the half-mile catchment area around proposed LRT stations.

But then there is the way to save real money. First, there would be no need for elaborate stations, just shelters on existing streets. Second, it has not been widely reported, but the state Department of Transportation has plans to add a lane in each direction along 15-501, even with the LRT. We propose that new lanes be reserved for the new transit vehicles, as well as private-self guided vehicles, which would pay a toll. The new vehicles could also go on the shoulder of I-40 and the Durham Freeway, much as some busses now do. Third, smaller, lighter vehicles would greatly change the controversial maintenance facility (ROMF). In fact, it might make possible new locations, and the (money saving) option of separating vehicle storage from vehicle maintenance. Fourth, the “compact neighborhood” idea, with high density around stations, need not be abandoned. In fact, the systems’ flexibility would allow some new clusters of dense development—for example at the corner of 15-501 and Garrett Rd., which has property ripe for redevelopment, as well as existing moderate income housing.

But wouldn’t our proposed technology be much slower than the LRT? For many users, trip time would be shorter, as they would not have to make a bus-to-train transfer. But there is another advantage, which we think is a distinctive one. As we have recently been learning from high end Tesla and other electric vehicles, electric engines make possible almost mind-blowing acceleration. So, a vehicle that moved at, say, 25 mph on a city street could quickly reach twice that speed or more once on the fixed guideway. This would both save time, and give a distinctive “feel” to the system.

We would like to close with the “elephant in the room.” This is the bedrock belief among light rail advocates that “people will not take busses, but people will take trains.” What we propose is neither a bus nor a train.. The high-tech bus transit system developed in Brazil (and diffused elsewhere in South America) has been affectionately called the “Ligeirinho “ (little quick one). Given the size and potential acceleration of what we propose, this would not be a bad name for a technologically advanced transit system here in the Triangle.

If Durham wishes to be a progressive city, it should shed its nostalgic love affair with 19th century steel tracks and be creative about its 21st century urban transit system.

Eric Ghysels is Edward Bernstein Distinguished Professor of Economics at UNC, Robert Healy is Professor Emeritus of Environmental Policy at Duke.