Width 
Width should be measured perpendicularly to cyclists’ trajectory and is rather straightforward to measure. The only considerations are whether to include in the width:
Most existing guidelines (see comparison in the table) give 4.0 m as recommended width for a bidirectional cycle path, and 2.5-3.0 m per unidirectional cycle paths. Minimum widths are respectively 3.0 m and 2.0-2.5 m. The numbers are based on the assumption of a bicycle needing approximately 1.0 m wide lane for riding:
The recommended width of a bidirectional cycle path of 4.0 m means that 2 cyclists can overtake or ride next to each other in both directions (2x2 “lanes”). The minimum width of 3.0 m means one cyclist in each direction and a spare lane for overtaking or riding next to each other in more popular direction (e.g. in the morning to the centre, in the afternoon toward the suburbs).
| Guidelines/standard title | Region/ country/ organisation | Width, two-way cycle path | Width, one-way cycle path | Width, one-way cycle lane |
|---|---|---|---|---|
| Design Manual for Bicycle Traffic | CROW, Netherlands | 4.0 m | 3.0 m | not recommended for CH |
| Vademecum Fietsvoorzieningen | Flanders | 3.0 m or 4.0 m, depending on the expected usage level | not mentioned as a solution | |
| Kwaliteitscriteria voor fietssnelwegen | Provincie Vlaams-Brabant | 4.0 m recommended, 3.0 m minimum | 2.5 m recommended, 2.0 minimum | not mentioned as a solution |
| Qualitätsstandards für Radschnellverbindungen | Baden-Württemberg | 4.0 m | 3.0 m | 3.0 m (or 2.75 m + 0.5 m buffer if parking is allowed) |
| Qualitätsstandards für Radschnellverbindungen reduziert (can be applied to 20% of route length) | Baden-Württemberg | 3.0 m | 2.0 m | 2.0 m (min. 1.85, with 0.75 m buffer from parking if it is allowed) |
| London Cycling Design Standards | Greater London | 4.0 m | 2.5 m | 2.0 m |
| Supercykelstier. Koncept 2.0. Planlægning, udformning og drift | Copenhagen | 2.5-4.0 m, depending on cycle traffic; bidirectional paths along roads not allowed with more than 1500 cyclists/peak hour | 2.25-3.5 m, depending on cycle traffic | not recommended for CH |
| Manual for the design of cyclepaths in Catalonia | Catalonia | 2.5 m (recommended); 2.0 m (minimum) | 2.0 m (recommended); 1.5 m (minimum) | |
| Réseau cyclable à haut niveau de service. Objectifs et principes d'aménagement | Cerema / France | 4.0 m recommended, 3.0 m minimum | 3.5 m recommended, 2.5 minimum |
Space is a precious resource, and, in some cases, it might not be feasible to provide the recommended width in corridor that would be optimal from the point of view of other criteria (e.g. directness, attractivity, connectivity). The decision whether and how much to prioritise width over other qualities might depend on the (expected) volumes of cycle traffic.
In case of interruptions cycle paths need to be wider before the stopping place, to provide space for accumulation of cyclists waiting e.g. for a green light.
Cycle paths need to be widened also on slopes. Cyclists going uphill need more space for maintaining balance; going downhill – more space for safety buffer because of higher speed.
The choice of width might depend on the expected cycle traffic, specific values are given e.g. in “Supercykelstier koncept 2.0” (Copenhagen).
As for the buffer zone from motorised traffic, it is required for bidirectional cycle paths. For example, “Supercykelstier koncept 2.0” (Copenhagen) requires at least 1.0 m distance inside and 1.5 m outside build-up areas. CROW’s “Design manual” recommends at least 0.35 m in build-up areas and 1.5-10.0 m outside, depending on speed of motorised traffic.