Nearly 20 years ago, I attended a conference on road pricing. The piece I wrote about it (PDF) for Infosecurity magazine suggests it was in late 2007, three years after transport secretary Alistair Darling proposed bringing in a national road pricing scheme. The idea represented a profound change; until a few years earlier, congestion had always led to building more roads. In 2003, however, London mayor Ken Livingstone implemented instead the congestion charge – and both traffic and pollution levels had dropped.
So this conference explored the idea that road pricing would cut traffic to match road capacity, taking us off the vicious spiral of increasing road capacity and watching traffic rise to choke it. Darling’s proposal was for a satellite tracking following a 2004 feasibility study. In 2007, however, prime minister Tony Blair effectively dropped the idea after 1.8 million people signed a petition opposing it.
This week’s announcement of road pricing for electric vehicles is rather differently motivated, but reawakened my memory of the 2008 discussion. Roads must be paid for somehow, and, as foreseen by the the Institute for Fiscal Studies in 2012 the rise of electric vehicles inevitably eats away revenues from fuel taxes. EVs have many benefits: they can be powered without fossil fuels; their engines emit no carbon or other pollutants; and they are quieter. However, they weigh 10% to 30% more than internal combustion engine vehicles, and tire wear remains a significant pollutant.
Back in 2005 there were three main contenders for per-mile road pricing: automated number/license plate readers; tag and beacon; and time-distance-place. At the time, versions of these were already in use: the first was in place to administer London’s congestion charge; the second, effectively an update to paying at the tollbooth, was in place on turnpikes in the American northeast and in the UK at Dartford Crossing; the third was being used in Germany’s HGV system, which collects tolls for the kilometers driven on the country’s autobahns. In a 2007 paper, Cambridge researchers David N. Cottingham, Alastair Beresford, and Robert K. Harle analyzed the technologies available.
Whatever you call them, limited-access highways – autobahns, motorways, interstates, thruways – are a relatively simple problem because there are relatively few entry and exit points. Tracking, as transponders read by automated tollbooths have made possible, remains a privacy concern. Such a scheme was deemed unworkable for London, where TfL counted 227 entry points to the most congested area, and barriers would simply create new chokepoints. For this reason, and also because it estimated that 80% of cars entering the congestion zone are infrequent users, TfL opted for a system of cameras that read license plates on the fly and an automated system to send out penalty notices if someone hasn’t paid. This system also seems difficult to imagine scaling to a national level; every road, street, and back alley would have to have ANPR cameras. In the US, where Flock cameras are collecting ANPR data at scale, law enforcement and immigration authorities are already exploiting it in anti-democratic ways, as 404 Media reports.
In 2008, TDP, a much more likely approach for a nationwide system of per-mile pricing, would have required a box to be installed in every vehicle to track it, likely via GPS, and report time and location data via mobile networks for use to calculate what the owner should pay. No one was then sure whether road users would accept having tags in their vehicles or be willing to pay the considerable expense; as I seem to have written in that 2008 Infosecurity article, “‘We’re going to change your behavior and charge you for the privilege’ isn’t much of a sales pitch.” But such a system would enable proportionately charging people based on their actual road use.
If we were updating that discussion, parts would be unchanged. Congestion charge-style ANPR cameras everywhere will be no more feasible than then. Germany’s system for motorways will similarly not be feasible for smaller roads and within cities. TDP, however…
Here in 2025, most people are already carrying smart phones with GPS just part of the package. So there could be a choice: buy a box that is irretrievably embedded in the vehicle or download a TDP app that’s somehow tied to and paired with the car, perhaps via its electronic key, so that it won’t start unless the app-car link is enabled. (Fun for anyone whose battery dies in the course of an evening out.) In addition, cars already collect all sorts of data and send it to their manufacturers. So it’s also possible to imagine a government requring manufacturers active in the UK to transmit time and location data to a specified authority.
Obviously, the privacy implications of such a system would be staggering. Law enforcement would demand access. Businesses whose fleet patterns are commercially sensitive would hate it. And the UK’s successive governments have shown themselves to be highly partial to centralized databases that are built for one purpose and then are exploited in other ways. For this reason, Beresford’s idea in 2008 was for a privacy-protecting decentralized system using low-cost equipment that would allow cars to identify neighboring non-payers and report only those.
The good news is that the details we have so far government proposals suggest something far simpler: report the odometer reading at each year’s annual vehicle check and multiply by the per-mile charge. So unusual these days to see a government propose something so simple and cheap. Whether it’s a good idea to discourage the shift to EVs at this particular time is a different question.
Illustrations: A fork in a road (via Wikimedia).
At Plutopia, we interview Bruce Schneier about his new book, Rewiring Democracy, which examines the good and bad of what AI may bring to democracy.
Wendy M. Grossman is an award-winning journalist. Her Web site has an extensive archive of her books, articles, and music, and an archive of earlier columns in this series. She is a contributing editor for the Plutopia News Network podcast. Follow on Mastodon or Bluesky.