The European Cyclists’ Federation (ECF) has published a new state-of-the-art report on geometric design standards for cycling infrastructure. The report gathers data from 15 different European countries with a diverse range of climates, levels of cycle use, population densities and topographies. Using the collected data, it then provides an analysis of the different standards and guidelines with varying levels of detail and scope.

The report compares design speeds of cycling infrastructure implemented across different countries and regions and the key parameters determined by them, such as horizontal and vertical curve radii and sight distances. These parameters are key factors in determining the geometric standards for cycling infrastructure across Europe.

You can download the report here.

Why are quality requirements for cycling infrastructure important?

Often there is political will and funding to build something for cyclists, but due to a lack of technical know-how, public money is spent on infrastructure that is not usable or unsafe to use.

The European Parliament and the Council of the EU recognised the problem, and in the 2019 revision of the directive on road infrastructure safety management obliged the European Commission to develop quality requirements for infrastructure for vulnerable road users, including pedestrians and cyclists. The quality requirements will be developed by a subgroup of the Expert Group on Road Infrastructure Safety, which ECF has applied to join.

Image 1. Bicycles travel in curves and will not change direction at right angle – even this basic principle is not universally known among infrastructure designers across Europe, as shown with this recently built cycle track in France.

Image 2. Once again, the basic principle that bicycles travel in curves is overlooked, this time in Malta (Photo credit: James Wightman).

Bicycles travel in curves

Geometric design parameters are an aspect of quality requirements critical for the safety and inclusiveness of infrastructure. Bicycles need to maintain a certain speed to keep their balance. They travel in curves and cannot change direction at straight angles. Sharp turns make it difficult for cyclists to stay on track or maintain stability – and difficult for other road users to predict the bicycle’s trajectory.

Poor geometric design can lead to falls, “run-off-the-road” accidents and collisions between cyclists, other vehicles or pedestrians. Unsuitable geometry can also exclude some user groups, particularly those who need dedicated cycling infrastructure the most, such as elderly cyclists, parents with children and cyclists with disabilities. 

Common patterns

The analysis revealed common patterns, but also surprising differences, gaps and internal inconsistencies. Most standards agree that:

• Main cycle tracks should be designed for speeds of at least 30 km/h.
• This translates to minimum horizontal curve radii of 20-25 m.
• Design speed and all related parameters need to be increased on downhills – most commonly, by 2 km/h per 1% gradient.

Many also point out that:

• On stabilised gravel and similar surfaces, higher geometric design parameters are needed than on asphalt, because of lower friction coefficient.
• Cycle tracks needs to be wider in curves.
• Higher design speeds, from 35 to 45 km/h, should be used for cycle highways and outside built-up areas.

Figure 1. Comparison of requirements for horizontal curve radii on asphalted cycle tracks in national and regional standards and guidelines. 

Differences and inconsistencies

The requirements for vertical curves vary drastically between different countries. Some standards set the minimum radius relatively low (10-40 m), others go as high as 250-300 m (up to 1370 m in Finland).

The provisions for calculating the stopping sight distances are also based on a wide range of assumptions. Different countries assume cyclists’ reaction time (the time between noticing an obstacle and the start of braking) between 1 and 2.5 seconds, and deceleration (“speed of braking”) between 1.5 and 3.4 m/s2.

Image 3. This obstacle, hidden behind a vertical curve for the cyclists coming downhill from the opposite direction, was the cause of a serious accident. Photo credit: Agnieszka Fabiańczyk.

The systematic review also revealed internal inconsistencies. Several standards do not provide one or more parameters for the design speeds they recommend. In a few cases, different parameters are recommended in different parts of the documents.

You can download the report here.