Leiden has the highest risk of traffic accidents on roundabouts in the Netherlands, according to a new analysis by traffic consultancy Goudappel. Other densely populated cities, including The Hague and Alphen aan den Rijn, also rank high, while Amsterdam is placed 14th.

The ranking is based on the number of accidents in relation to traffic movements and shows that roundabouts in cities with many cyclists and limited space are particularly risky.

“Densely populated cities with lots of cyclists and little room often have the most dangerous roundabouts,” traffic expert Rico Andriesse of Goudappel told the Leidsch Dagblad newspaper.

In particular the research found that roundabouts where cyclists do not have priority are generally safer. Accidents also occur more often at quieter roundabouts. Leiden has relatively few quiet roundabouts, but many where cyclists have priority.

Faster cycling speeds are another contributing factor. “We cycle more and faster than before, partly because of e-bikes and fat bikes,” Andriesse said. “Many roundabouts are not designed for cyclists travelling at 25 kph. Motorists often see fast cyclists too late.”

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The design of cycle paths also plays a role. The research shows that roundabouts with two-way cycle paths are slightly safer than those with one-way paths. This is because motorists are more aware that cyclists can come from both directions and additional safety measures are often in place.

With one-way cycle paths, drivers may assume cyclists only come from one side, while some cyclists ride against the traffic anyway.

Lack of uniformity

The study also points to a lack of uniformity in roundabout design and traffic rules, even within the same council area.

“Road users are constantly having to interpret different signs, markings and priority rules,” Andriesse said. “Uniform design rules make roundabouts more predictable and safer, reducing confusion and accidents.”

Leiden council told the paper it will first study the Goudappel report before responding to the city’s high ranking.