The behavioural roadmap

Leigh Crymble
5 min readJun 11, 2022

The latest World’s Safest Roads survey is out and it’s bad news for us in South Africa — out of 52 countries profiled, we ranked the worst. With 14 000+ road fatalities each year, costing approx. R147bn, we went looking for the best behavioural interventions to help improve road safety 🚗

Nudges to drive better behaviour

New insights into road safety show that behavioural solutions can help reduce road accidents and encourage better driving. Behavioural initiatives or “nudges” help to modify our environment and influence how we act.

Global case studies demonstrate how well these types of nudges work — transcending regions, cultures, demographics and psychographics to appeal to all. And the good news here is that these ‘levers’ can be quick, easy and inexpensive to implement.

All you need is … paint

An effective behavioural nudge to get drivers to slow down involves a few cans of paint and some strategic white stripe placement. This was piloted in Chicago at an accident hot-spot due to a sharp bend in the road. The solution was a series of horizontal white lines that got progressively narrower as drivers approached the sharpest point of the bend. This gives the illusion of speeding up, therefore nudging the driver to slow down. The outcome? 36% fewer crashes in the six months after the lines were painted.

In another behavioural experiment, zigzag white markings were painted in place of the usual straight dashed lines on the road. This less-familiar road marking successfully slowed average vehicle speeds and increased drivers’ awareness of pedestrians. Importantly, researchers found that these effects didn’t wear off as drivers became more used to the new design — with the more cautious driving still being demonstrated a year after this nudge installation.

Next: in Philadelphia, Phoenix and Peoria, the US National Highway Traffic Safety Administration painted 3D speed humps on roads to encourage drivers to slow down in busy areas.

Other examples included 3D pictures of animals and children painted on the roads as drivers approached pedestrian crossings and cycle lane intersections.

Try carrot (or stick)

As Discovery Insure drivers already know, better driving = better rewards. Programmes such as Vitality Drive incentivise safer driving using telematic-tech to award driving points and score a driver based on their driving behaviour. Discovery data shows that their (engaged) members exhibit safer driving behaviours, and have fewer and less severe accidents.

Lottery-style rewards have also proven successful as part of a road safety strategy. Stockholm experimented with financial rewards for drivers who drove at or under the speed limit. Dubbed the ‘speed camera lottery’, compliant drivers were automatically entered into a monthly draw with the chance to win a monetary prize — funded by fines from the speeders.

Latin America offers one of the most interesting (read: bizarre) interventions. Playing off of social norms, Colombia used traffic mimes to mock and shame drivers as part of a successful social proofing campaign to tame traffic violators.

Add a visual trick

From the animate to the inanimate, life-size cut outs of traffic police have been used in Bangalore to dissuade motorists from committing traffic violations — we’ve seen this in Green Point, Cape Town too!

Make numbers nudgey

Instead of the usual whole number speed limits, try the ‘left-digit-effect’. Used commonly in retail environments (think R49.99 instead of R50), studies have shown that the psychological effect of 59.51km/h speed limit signs — instead of the familiar 60km/hr — reduced average speeds by as much as 2km/hr.

A note of caution here is that anything too distracting should be avoided. A study in Texas demonstrated this type of intervention backfiring with multiple instructions on road-side signs distracting drivers and ironically leading to increased incidents.

Unique noise nudges

Adding protruding “rumble strips” where small sections of the road are raised at intervals is another behavioural design nudge worth trying in hazardous accident zones. When the driver reaches this area, the textured surface makes an unpleasant grating noise — which is reduced only through slowing down — with no damage done to the vehicle.

Plant some trees

Norfolk County Council in the UK planted 200 trees along a highway that was known for speeding-related accidents. These trees were planted equidistant from each other, up until the driver approached the village. At this point, the trees were planted closer and closer together, to give the impression that the car was moving faster. Results showed that drivers slowed down by an average of 3km/hr. Good for the roads — and the environment!

Driving behavioural change

With budgets stretched and road fatalities at an all-time high, we must consider alternative solutions to help improve road safety. These tried-and-tested simple and practical behavioural nudges may just be the answer.

All the more reason to introduce them to our roads — before we start planning our next local road trip.



Leigh Crymble

Leigh is a doctoral student at Wits Business School and the founder of BreadCrumbs Linguistics.