Trees and traffic

If you ‘google’ a term such as ‘roadside trees, traffic calming’, you will get several million results – how did we do our research before?

Main South Rd

Cars will always be a part of the urban landscape and any engineering that can accommodate them safely is welcome. We have traffic lights, roundabouts, chicanes, speed humps and many other measures to help create a safer environment for all road users.

McGlone Rd

World-wide research indicates that roadside vegetation, trees in particular, can play a vital role in calming traffic and reducing accidents. Roads that are tree-lined can reduce average speeds by as much as 12 km/h.

Princes Way and Wellwood Rd

One theory suggests that something called the ‘edge effect’ provides drivers using tree-lined roads with a mental prompt to drive more slowly. A tree-lined road is perceived as being narrower than it actually is.

In the USA, an analysis of a section of ‘bare’ road after some perimeter tree planting, showed a decrease in the rate of accidents by 46%. Understandably, authourities are reluctant to accept these findings as they contradict the normal belief that roadside obstacles should be at a minimum for safety.

Princes Way east

In 2018, a little closer to home – Freemantle WA – the residents of one LGA voted overwhelmingly for median strip tree plantations over speed humps as a means of calming traffic.

Shillinglaw Rd

One UK study suggests that levels of ‘road rage’ are reduced considerably on road networks that involve natural roadside vegetation.

Waddell Rd

Obviously, there will be particular situations that will mean trees will not be the best solution for traffic calming but it seems a ‘no brainer’ that, where we already have stretches of road which are lined with magnificent tree corridors, we should be doing everything possible to retain them.