OPINION: The big policing problem with 20mph speed limits

The proliferation of 20mph speed limits in Norfolk - particularly in Norwich – suggests that they reduce accidents and personal injury, but do they?

My Norfolk village has almost a one-mile stretch of 20mph restriction running through its centre. It has been in force now for 20 years yet the majority of vehicles speed through at 30mph plus, especially lorries, coaches, vans and SUVs that are impervious to the speed humps.

In all those years I have never seen a speed safety camera in action or any other kind of enforcement. The speedsters know that because they are “regulars”.

It would be great to have a speed camera installed in our village, so my interest was piqued when I read about a camera being installed in 20mph West End, Costessey, which has long been used as a “rat run”.

But I was disappointed to learn in the EDP report that, while the sight of the camera may cause drivers to slow down, motorists will not be prosecuted; the data from the camera will instead be used to target “educational messages”.

So why are speeding drivers who ignore the limit not held to account in the same way as in a 30mph limit?

The answer is elusive and frustrating in equal measure. I contacted Norfolk Police press team for a better understanding.

There is a difference between a 20mph limit and a 20mph zone. A zone is an area that would normally have other speed reduction engineering in place, such as speed humps or similar, to actively reduce the speed of vehicles.

A zone can be introduced by a local authority without any permissions being sought. However, this can create a significant issue for enforcement, says the police.

If a zone is introduced without a traffic order, then the speed limit applicable will be 30mph as it will fall within the remit of a restricted road, despite the advisory 20mph signs.

Confused? So exceeding 20mph where there is an order is an offence. But if there is not an order the limit is 30mph. But with no cameras and no police enforcement it is not a deterrent in either circumstance.

The Department for Transport Circular ‘Setting Local Speed Limits’ states that: “Successful 20 mph zones and 20 mph speed limits are generally self-enforcing, i.e. the existing conditions of the road, together with measures such as traffic calming or signing, lead to a mean traffic speed compliant with the speed limit.”

It goes on: “To achieve compliance there should be no expectation on the police to provide additional enforcement beyond their routine activity. Where 20mph speed limits or zones are introduced, general compliance needs to be achievable without excessive reliance of enforcement.”

Peter Franzen (Image: Archant)

In my exchange with Norfolk Police, it did say it will take action around enforcing 20mph limits where there is clear evidence of non-compliance, or injury collision data supports that action.

I requested data to show how many drivers had actually been prosecuted over the last 18 months in Norfolk for speeding in a 20mph limit. I was told I would need to fill in a Freedom of Information request. I did. The answer? None in Norfolk and just three in Suffolk.

It makes sense that driving at higher speeds increases the chances of both drivers and pedestrians being injured in an accident, which is a strong argument for creating 20mph restrictions.

One study found that collisions at 20mph had a 2.5% chance of fatal injury for pedestrians, compared to 20% at 30mph, while another study found the same risk to be 1.5% at 20mph and 8% at 30mph. In both cases, it’s clear that lowering speeds does improve survival rates.

Confusingly, studies have also shown that minor accidents actually increased in 20mph areas. The Institute of Advanced Motorists, based on data collected by the Government, has shown that minor casualties increased by 19% while major casualties in these areas saw a 29% increase.

It seems that it is not clear cut. But local authorities still favour 20mph restrictions in built-up areas, even though drivers can flaunt the limits without fear of redress – and too many do.

We know that speed cameras make drivers observe the limit for fear of fines and bans. Clearly Norfolk and Suffolk police have neither the will nor the resources for enforcing 20mph speed restrictions.

For them to be really effective they should be included in the UK national speed limits criteria and have the same gravity as other national limits. Without enforcement these low-speed zones will not slow the speedsters who don’t give a hoot.