Nudging traffic: How to save lives in a hurry

By Katrine Lund Skov & Andreas Maaløe

I’m a little late again. Driving a bit too fast, but what the hell, if that’s what it takes to avoid the bosses accusing glance of ‘you’re-late-again’ then it’s worth it right? Speeding just a little can’t be that dangerous anyway. Tomorrow I’ll get out of the door in time. I promise!

Habit and overconfidence on the road
How many of the 2381 persons that got injured or killed in traffic last year reasoned somewhat like the above before they got in their cars? Or the previous year, where that number was 2801. The good news is, that this year the number of accidents and fatalities has gone down by 500, so what happened? To answer that question we must first understand what caused the accidents. In a review from the Danish Road Safety Council, 75% of the interviewed speed offenders said it was due to a lack of attention from their part, because they were in a hurry or the thought that the road conditions invited faster driving.

If anything, our behaviour in traffic is mostly automatic, something we do everyday without thinking, a habit. The potential catastrophic consequences of bad driving are hard to imagine. In addition, it always happen to someone else – right? In behavioral economics this latter bias in judgement is known as the overconfidence effect. When you ask a class of students, usually 90% estimate that they will do better than the average on the final test.

Finally, and the only feedback we get from erroneous driving is when its too late.

Nudging for traffic safety

We can hardly argue that we don’t know the rules of the road, and with automatic behaviour, little feedback and abstract (but deadly) consequences, driving is in need of a nudge, where the trick is to make the drivers behaviour salient with driver feedback signs.

Credit to Jim Parkin

When feedback signs were erected on the Øresund Bridge the amount of drivers that exceeded the 40 km speed limit was cut in half, which significantly lowed the risk of accidents for the staff working there and for drivers themselves. Feedback signs remind us of our behaviour right there and then, which in turn forces the driver out of the automatic behaviour pattern – she can still speed with no economic sanction, but now the speeding becomes a choice instead of habit.

Individual salience is one thing, but perhaps more interesting (from a nudge perspective) is the trafficants desire to drive at the same pace as that of their peers. By informing drivers about other drivers actual speed, a significant impact can be made on how many drivers choose to adjust the speed they are travelling. Most drivers erroneously believe that everyone else is speeding – which in turn makes them speed themselves.

So – driver feedback signs coupled with strategic information about the behaviour of peers seem to be the way forward, and if you’re wondering about if it’s all worth it, just think of the 255 who could still have been alive this year if national speeding had been reduced to the same levels as those on the Øresunds Bridge.

Next post: Nudging traffic safety by visual illusions