Besides responsible behavior, bicycling safety cannot exist without adequate infrastructure. Every region that has created a culture of safety, has made efforts to create safe roads and paths for all types of road users.
We intentionally speak of ‘road users’, or traffic participants, and not of cars, bicycles or trucks. Vehicles do not make decisions (at least not yet) and bear no responsibilities for their actions. It is humans, whether they are riding, walking or driving, that interact with each other in traffic and if we want safety, we need to focus on human behavior.
But responsible behavior only gets you so far in an inherently dangerous environment. What does a safe city infrastructure look like?
Separation of traffic types
A most important principle in creating a safe traffic environment is separation of traffic types. As can be seen in the video, the Netherlands has been successful in separating traffic types. Why is this important? Because of differences in speed. Every time road users with different speeds encounter each other, even going in the same direction, there is risk of collision. The higher the speed difference is, the higher the risk. This is a reason we have sidewalks. (Another reason is that we don’t want to slow down traffic unnecessarily).
When we define bicycle riders, we think of everyone who is able to ride independently, including children who are old enough to ride without supervision.
The danger for pedestrians and bicycle riders is increased because of their physical vulnerability. To streamline traffic and create safety for the vulnerable (or actually all) road users, if possible, separate paths have to be created for the three categories: pedestrians, bicycle riders and drivers of motorized vehicles.
Different streets require different speeds
This cannot be done everywhere. For instance, some streets do not have room for separate bike lanes. In these cases, measures have to be taken to equalize speed between traffic, such as a reduced speed limit paired with enforcement, or adaptations to street design.
A safe speed for motorized traffic on mixed-use roads is such that drivers of motorized vehicles have sufficient time to slow down or stop when suddenly a pedestrian or bicycle rider gets in the way. Such a safe speed cannot be much higher than 25 miles per hour. But before we get all worked up about this, it should be noted that residential street should be treated different from thoroughfares.
By thoroughfares we mean: streets that provide a transportation function to people outside of the street area itself. In other words, roads that people must use to get from A to B. On such streets, if bicycle traffic is allowed, it must be separated from motor vehicle traffic.
In residential streets, on the other hand, where all types of traffic have to interact, speeds must be reduced to the lowest safe denominator, that is a speed where everyone can use the street safely.
Bike lane or bike path?
It depends on relative speed of traffic participants and, as a practical matter, space available in the right of way. If speed difference between unmotorized and motorized traffic is modest to low, bike lanes will do fine. For instance, if the speed limit is not above 35 mph, bike lanes of sufficient width should be acceptable in terms of safety.
Beyond that speed, to provide a safe portion of the street for bicycle riders of all ages, bike paths should be separated from car lanes by a median or a physical barrier.
It there is no room for a bike path, vehicle speeds must be reduced.