For the last few months a consultation has been on-going on lower speeds in our neighbourhood - around the local Addington School. And last month it was finally approved.

Many of the local roads will be 30km/h. This is lower than the initially proposed 40km/h - but sanity prevailed at the community board meeting and they counter proposed to Waka Kotahi that 30km/h is more in keeping with scale of the streetscapes and environment. This is a huge win for the community. It has long been a nonsense that the narrow streets of Rosewarne, Sommerset Crescent, and Willard Street had a posted speed of 50km/h. And the posted speed has been changed on Selwyn Street to 30km/h as well. This is the section that passes through the Selwyn Village Shops, so crossing will be much safer. However we still do not have road markings to reinforce the speed change - and I will be especially interested to know if there will be any tracking of speeds and enforcement.

It has long been a axiom that posted speeds should be set at a level where 85% of cars naturally travel at that speed. And so Waka Kotahi is reluctant to reduce speeds when they measure the speed and people are travelling at 50+km/h. But as the Strong Towns article above notes - this is a standard for open roads - not for residential streets. Instead we need to set speeds that are safe for the street, and all users - including cyclists and pedestrians.

The notion of setting a speed that 85% of people naturally drive at is intuitively sound - but it is the edge cases that cause problems. Not everyone will drive dangerously, and recklessly cause a death or injury - but when it is enabled by the 85th percentile model the recklessness is due to institutional ineptitude. I've mentioned that our two way residential street is one-way most of the time, with pinch points and parked cars that reduce the width. Most people drive slowly and give way - but it is entirely legal to drive at 50km/h - that's the posted speed... even if it would be reckless to do so.

But this also points us towards how we should design our streets - if we want lower speeds we need to change the streetscape to encourage the natural speed to lower. This is not to say we should not ALSO lower the posted speed - but along the Selwyn Street section is it likely the 30km/h speed will be exceeded. I even forget when passing along this section.

We need more pedestrian crossing bump-outs, more raised speed tables, and more street trees to reinforce the residential nature of the street.

But why reduce speeds anyway? Because there is a direct and dramatic relationship between speed and the seriousness of accidents. Waka Kotahi are well aware of the problem.

So a two pronged approach is required - change the posted speeds, and change the streetscape to reinforce the speed expected. Low Traffic Neighbourhoods are part of the solution too. Fewer vehicles moving slower means a safer environment.

Surely it is obvious that collector and arterial roads have a different function to local roads. There should be an immediate change to the posted speeds - streets not designated as collectors or arterials should have a posted speed of 30km/h.

No one should be in such a hurry that they would risk the lives of others. The reduction would also discourage rat-running - especially if in conjunction with Low Traffic Neighbourhoods... and it is increasingly obvious that LTNs need to be renamed. The focus should be on the safety of residents - not named for the traffic. Perhaps Family Friendly Streets, or Our Safe Streets.

But in any case - Low Speed should be required. So the new changes in the Selwyn Village - Addington School area are very welcome.