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How to design bicycle lanes that are safe and functional

16 of May of 2024

Bicycle lanes are basic infrastructure for sustainable mobility, like a pavement or a road used for public transport, and involve significant engineering to determine their optimal layout, materials, protection and functionality. But how are bicycle lanes designed? How to design bicycle lanes that are safe and functional?

We place both safety and the perception of safety at the center, but without forgetting aspects such as convenience, physical effort, shade, parking at origin and destination, and the integration of groups of all ages and abilities. Designing good cycle lanes is not a trivial problem; it requires considerable dedication and resources.

The three elements that should never be missing in cycling infrastructure

To be able to speak of functional, accessible and usable cycling infrastructure for the whole population (including children, people with reduced mobility and the elderly), bicycle lanes must be deployed with at least the following elements:

  1. Bike racks at the origin and destination of the journey, so that cyclists can park their bikes.
  2. Cycle lanes that are protected and, if possible, segregated from road traffic.
  3. Lanes connected in a larger cycling network, because without network density potential trips will be very limited.

When all three elements coincide in the same urban framework, then the phenomena of induced demand and traffic evaporation begin to be observed: modal transfer from the car (the evaporated mode) to the bicycle (the induced mode).

1. Bike racks at the origin and destination of the journey

For cycling to be used as a mode of transport, it is essential that there is a place to park bicycles both at origin and destination, e.g. a space at home and at work, but also in front of shops, schools and council buildings. In addition, a bike rack should ideally meet the following conditions:

  • Occupy space on the parking strip next to the pavement, never on the pavement, both because cycling is not allowed on the pavement and in order to take space away from less efficient and more polluting vehicles.
  • Anchorage of both wheels and frame, with the U-inverted or similar structure recommended to attach front wheel plus frame on one side, and frame plus rear wheel on the other.
  • Protected from heavy vehicles or containers to prevent the bicycle from being hit. This can be done by means of bollards and other static elements.
  • Placed away from surfaces such as facades by 70 cm, so that the bicycle wheel can fit. If the bike rack is installed flush with the facade, the bicycle will not fit.
  • Be securely anchored to the ground and never loose or mobile. It must not be easier to remove the bike rack itself than one of the wheels.

In addition, it is highly recommended, especially in places such as commercial outlets, to avoid locating bike racks in underground or roof parking areas. The bike rack should be visible from the street and, if possible, located in front of the shop in such a way that getting in or out does not require any effort. Also, bike racks should not be placed in dark or inconspicuous places to avoid theft. The best place is one that is visible to all.

2. Protected and, if possible, segregated bike lanes

Protected lanes are the cornerstone of urban and interurban cycling infrastructure, making it easier for people who would not have considered this type of mobility to switch to it (preferably from polluting modes of transport, although even a transfer from public transport is also good for physical activity). And if safety is key, a sense of safety is essential.

There are several indices that classify how safe or unsafe a given piece of infrastructure is perceived to be. In the United States, pedaling stress levels are commonly used, with LTS1 (Level of Traffic Stress 1) being the feasible level for an 8-year-old to an 80-year-old (the 8-80 city concept emerges as an alternative approach to car-centered urban design), while in Central Europe the characterization of subjective safety is more straightforward: safe, fairly safe, uncertainly safe, safe.

Studies on this subject leave no room for doubt: the lack of a bike lane is considered the most unsafe, followed by painted separation, followed by a physical separation with planters. And the best? Lanes on which a car is physically unable to drive, either because they are segregated or because the vehicle does not fit (bollards). What is most interesting is that both motorists and cyclists agree on these conclusions.

Generally speaking, all bike lane design guidelines (here, here or here) agree that 1.5 meters is the minimum distance for a cyclist to ride safely.

3. Connected lanes in a network

It’s not enough to merely provide isolated bicycle lanes in a city. Just as roads are connected in a network and it is possible to travel safely from any street to any other, the cycling network has to be connected to itself, taking people where they need to go. This has been achieved over recent decades by laying radial lanes connecting parks and other cycling networks often far from urban centers.

If the 20th century was characterized by a colonization of the city by the car (which helped to co-create it in its own image), at the beginning of the 21st century, patches of active mobility network are being connecting together. Almost all cities already have a perimeter ring-type network designed for sports, but these are not particularly functional for mobility as they tend to be located far from where people work. However, a good starting point is to extend radial trips to the interior of the city, and even further out to other municipalities.

In the layout of new cycle roads, of which shared infrastructure such as sidewalk-bike lanes or cycle paths are excluded from the computation of cycle lane kilometers (although they add up as ‘cycle paths’), it must also be borne in mind that cycling mobility is active and therefore requires a minimum physical effort even with pedal assistance. Laying out lanes on the perimeter of parks, on wind-protected and shaded streets, or on roads where there is no other vehicle traffic is also important to promote adoption.

If you build bike lanes, will cyclists come?

“If you build them, they will come” has been a maxim of urban planning for bike lanes since the late 1960s, a concept associated with induced demand, which we can summarize as if you provide safe and more convenient alternatives, people will use them. This is a valid principle for any transportation system, but it becomes especially relevant for bicycles because it allows people to avoid excuses such as snow, heat or excessive slopes. The real barrier is the lack of bike lanes because, if they are built, they are used.

However, as we have seen previously, not just any layout will do. What good is a bike lane if it doesn’t get me from home to work, or if I have to make a lot of turns, or if it suddenly disappears and becomes a lane shared with cars and therefore unsafe for my children, or if it is not cleaned and is full of leaves?

The three principles above are a minimum standard to induce cycling mobility, but they have to be combined with others such as good maintenance, consistent signage, a layout that connects residential centers with work and commercial centers (if they are not already combined, which is ideal), a width that facilitates ‘social pedaling’ (just like walking while talking, pedaling while conversing is a reality in more advanced countries) and makes safe overtaking possible, and that does not compete with pedestrian space.

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