The most common bicycle accident type at roundabouts (traffic circle intersections) has been shown to be between the entering driver and the circulating cyclist. This study, based on video recordings, shows how the behaviour of drivers entering the roundabout depends on the traffic situation on it. A test cyclist was provided to create well-controlled conflict situations during the recordings. Drivers' adjustments to the cyclist were measured in terms of approaching speed, head movements, and the manner in which they yielded to the test cyclist nearing the joint-conflict point at the bicycle crossing on a collision course, from either the left or right. Six roundabouts in Finland, Sweden, and Denmark were included in the study with varying roundabout layouts. The approaching speed of cars was lower at roundabouts with large central islands than at those with smaller central islands. The majority of drivers adjusted their visual search pattern adequately, even when the cyclist came unexpectedly from the right (opposite of motorised traffic). However, 7-15% of drivers did not look at all at the cyclist when he was approaching from the right. Higher vehicle approach speed contributed to drivers not looking to the right and to not yielding to the cyclist. Results suggest that priority regulation at bicycle crossings should vary depending on the location of the crossing at the roundabout. (A)
Abstract