Road signs depicting childrens's book illustrations temporarily reduce speed on urban roads

Speeding on urban roads is a major road safety problem. Police enforcement and speed humps are effective measures to prevent drivers from speeding. However, these measures may also elicit none compliance because of their restrictive nature. Therefore, non-compulsive measures that nudge drivers to adopt low speeds are also required. One such a nudge was evaluated: road signs displaying children’s book illustrations. These signs display illustrations which were created by the late illustrator and writer of books for toddlers, Dick Bruna, and are named ‘Dick Bruna signs’. The idea of the developers of these signs was that they will evoke feelings of caution and care in drivers and this will make them drive slower. To evaluate the effect, two studies were conducted. In the first study participants watched photos from the driver’s perspective. They had to report how fast they expected others would drive and how fast they themselves would drive. Participants reported speeds of others higher than their own speeds but the pattern was the same: speeds on photos with a Dick Bruna sign were approximately 4 km/h lower than on the same photos without a Dick Bruna sign and speeds were not significantly lower when a neutral sign such as an advertisement was visible. In the second study speeds were measured during seven consecutive weeks on five experimental roads and five comparison roads. On the experimental roads, during the week 3–5 a Dick Bruna sign was placed. Controlled for developments in speed on the comparison roads in the same period, mean speed was marginally significant lower, and the V85 speed and the proportion of speed offenders were significantly lower in only the first week after placement of the signs.