Images

We’ve prepared some visuals to help the community share the big idea.

Effect on travel time

The extra benefits from speed limits higher than 30km/h in urban areas for drivers are marginal.
As 30km/h speed limits make the streets safe for sharing, we enable one of the most efficient transport modes for urban areas: riding a bike. Note the table is not meant to say walking is not important: walking combined with a good network of public transport is a great way to get around.

Speed vs safety

Speed vs cone of vision

Cone of Vision at different speeds. Credit: Claudio Olivares Medina

Street vs impact of travel time

In Munich and many other German cities 80% of streets have 30km/h limits. The Pareto principle (80/20 rule) can explain why it is widely accepted by drivers to share these streets as they are not important for their travel time. “80% of vehicles should circulate on 20% of the streets, and vice versa.”

Streets in europe

German 6 year old child walking to school on a 30km/h street (2020, Bad Toelz). Safe walking infrastructure does not always carry a high price tag: The majority of road safety experts we surveyed said a 30km/h environment as above is safer for children walking to school than a typical Australian neighbourhood with a footpath on one side of the road, no crossings and a 50km/h speed limit.

Typical 30km/h zone in neighbourhood in Germany. There are no cycle lanes in these areas as experience showed that a shared low traffic, low speed environment is safer for people riding a bike. There are no speed humps or chicanes to slow traffic down. Rather than “tricking” drivers into slowing down, driving too fast here is socially not acceptable and enforced by the councils.

Safe streets to school

A local campaign is using this image to campaign for safe-street-to-school. They are asking to separate their children from fast moving traffic by proving footpaths and crossing or 30km/h limits on the way to school.

Comparisons of different countries

Source: Evaluating Active Transport Benefits and Costs by Todd Litmann

Source: Evaluating Active Transport Benefits and Costs by Todd Litmann

Speed vs reaction time

The above graph is published by the German Automobile club. This data is for a good driver with quite a fast reaction time of 1 second and assuming good road conditions. Note that “thinking distance” is not dependent on how good your brakes are.
If you drive 30km/h and someone would step out on the road 15m in front of you, you would just stop in time. If you drove 50km/h you would hit the person with an impact speed of 50km/h.

Speed vs likelihood of dying in a collision

The kinetic energy is proportional to the square of the impact speed. Find out more about why “speed kills” is not just a marketing slogan but based on physics (the second law of motion). Best practice is setting speed limits according to the amount of biomechanical energy humans can tolerate without sustaining permanent injury.

Full slide deck: 30km/h speed limits for local streets

Big-Idea-pdf Download