Assessing the safety of international examples of bicycle streets to identify important design elements—an expert judgement

The two most common types of cycling infrastructure are separated bicycle tracks and bicycle lanes. Several studies have been carried out to examine their impact on cycling safety. A relatively new type of cycling infrastructure, which is increasingly being implemented, is the bicycle street, defined as a street where bicycle traffic is prioritised and where motorised vehicles are limited in terms of volume and speed. Since bicycle streets are developed recently, the literature about their safety is scarce. Therefore, in order to provide directions for further research to the safety of bicycle streets, the present study aims to identify which design elements of bicycle streets are important to assess their safety, based on expert judgement. The expert judgement data were collected from 49 cycling safety professionals, divided over ten groups, during a workshop about the safety of bicycle streets during the 11th International Cycling Safety Conference 2023 in the Hague. The groups of cycling safety professionals categorised nine international examples of bicycle streets over three piles: ‘Safest’, ‘In between’, and ‘Least safe’. They also provided arguments about why they put a bicycle street on a specific pile. These arguments are used to identify important design elements that impact the safety of bicycle streets and are compared to existing literature. The results showed that expert judgements are considerably similar across the example bicycle streets and their design elements. The most important design elements to assess the safety are: width of the street, design to prioritise cyclists, road markings and parking. The literature shows that for some elements, general road safety knowledge exists, but that for most design elements no studies exist that examine their relation to the safety of bicycle streets in particular.