Clearing Congestion

It can be difficult to effect behavioural change in large cities, but Stockholm and London have shown that a well-conceived nudge will deliver results.

Stockholm’s congestion charge was first trialled on 3 January 2006, but with hindsight Halloween would have been more apt. As in an act of sorcery, the queues of motorists typically found on the city centre’s main access routes disappeared overnight. Traffic decreased by around 20 per cent– 5 per cent above the target – allowing the remaining road users to move with newfound ease.

Nor did Stockholm’s vanished vehicles return in the following weeks and months. Intrigued by the scheme’s success, Jonas Eliasson and his research team at KTH Royal Institute of Technology set about tracking down motorists who had changed their routine, but with little success; it transpired that no one thought they were behaving differently. “Travel patterns are far less stable than you might think,” Eliasson points out. “Each day people make new decisions. People’s lives change and so does the world around them, and these factors can nudge decision-making away from rush-hour driving in ways people don’t even notice.”

With the transport landscape changing rapidly, how does Eliasson envision the future? “A rise in shared vehicles might address issues with parking, but that won’t solve the basic lack of space in an urban transport system. Congestion pricing must remain a necessary tool in the urban transport planner’s toolbox,” he says. “As more data are gathered and drivers become accustomed to pricing, charging a higher price in morning hours, or for certain routes or vehicles, may prove more effective.” London runs one of the largest congestion-charge systems worldwide, so is the story significantly different there? “The charge reduced private vehicle use by 20-25 per cent, which is the equivalent of 60,000-70,000 cars per day,” says Philipp Rode of the LSE Cities project, suggesting a similarly positive impact.

Despite the reduction in vehicles, traffic speed has continued to shrink over the past decade, particularly in central London. However, Rode points out that many other factors are at play: “The decline in car numbers has allowed the redistribution of public space away from cars to bus and bike lanes, as well as pedestrian areas,” he explains.

Rode’s point is telling. Ultimately these charges are not aimed at helping car drivers navigate less congested roads; they are a smart way to create more equitable, liveable cities. Rode is confident that broader progress can be made with more daring public policies. “The ubiquity of smartphones has made expensive cameras and infrastructure unnecessary, so I wouldn’t be surprised if we soon see a road-pricing revolution based on app technology.” The evidence suggests that positive public opinion and open, shareable data will lie at the heart of successful future systems.

Originally featured on www.technologist.eu