Getting the hump: Why is Greenwich Council’s rollout of 20mph zones so slow?

Greenwich Council decided to introduce a 20mph speed limit on all its residential roads in 2012. Six years on, the programme is still being rolled out. Yet in this time Lewisham has approved and implemented plans for a speed limit which now applies on all council-run roads. Eltham North’s Conservative councillor SPENCER DRURY says Greenwich is using out-of-date criteria which is holding the scheme back.

I have two questions for Greenwich Council. Why is it that six years after the decision to introduce a 20 mph zone for all residential roads in Greenwich, it has not happened? And why does every single 20 mph zone proposed include speed humps on almost every road?

In 2017, my ward, Eltham North, had two 20 mph zones introduced and in both of them almost every single residential road was carpeted in speed humps of some kind in the Council’s initial proposals.

I’ve now established that this is because the council is using out-of-date criteria, meaning that while Lewisham has introduced a 20 mph zone for its whole borough in a few years, six years after its initial decision Greenwich still has a patchwork of 20 mph zones, which seem inevitably to be based on expensive, car-damaging and cyclist-disrupting speed humps.

What is Greenwich’s policy?

In 2012, Greenwich’s cabinet decided to introduce a 20 mph zone for the whole borough. This was based upon some work done by backbench councillors, including Conservatives, who were broadly supportive of the proposal.

The 20 mph zone seemed more achievable in 2012 as the Coalition Government had loosened up the restrictions on 20 mph zones so that they did not have to contain speed humps every few yards, but could also be imposed through signs, roundels painted on roads or even through residents measuring speeds themselves.

The cabinet report report noted this change and accepted the recommendation that speed humps should only be used where the quickest drivers (85th percentile) were travelling at speeds of greater than 30 mph.

A year later, the Department for Transport acknowledged the change in ways 20mph zones could be enforced and published official guidance which suggested that you only needed speed limits where the average (mean) speed was greater than 24 mph.

It is this guidance which Lewisham is using when deciding where to place speed humps to help enforce its borough-wide 20 mph zone.

From a personal point of view, I think these two criteria are broadly similar and Greenwich can reasonably claim that the 30 mph for quicker drivers is roughly the equivalent of the 24 mph for average travellers.

So why are Greenwich proposing speed humps everywhere?

Having established Greenwich’s policy, I asked for access to the speed data collected when the proposals were drawn up for the Arsenal Road 20 mph zone in Eltham, which was consulted on in December 2017.

As the ward councillor, I was aware that residents of certain roads, such as Crookston Road and Arsenal Road, had expressed concerns about the speed of cars outside their homes. But for the vast majority of roads, there had been no speed concerns which had made it to me.

The data (which showed only the 85th percentile speeds) reflected my understanding, with Crookston Road having speeds of over 30 mph at a couple of points and others – such as Arsenal Road, Dairsie Road and Congreve Road – also having some speeds quite close to 30 mph on some stretches of the road.

These roads are often used as cut-throughs when the traffic is bad and so this was not a surprise. But all of the other roads had the overall speeds of the quickest cars at less than 26 mph, which would suggest to me that they did not qualify for speed humps under either the council’s or government’s criteria.

Then the proposals for the area were published. Lo and behold, there were speed humps in every single street (except Cornwallis Walk, which contains only 4 houses and is as short as it sounds). Even in Castlewood Drive, a steep, narrow road where people park on both sides of the road so two cars can’t pass and the quickest cars achieved only 21.7 mph, the council thought speed humps were required to reduce speeds.

I simply couldn’t understand this as the proposals seemed to bear no resemblance (as they hadn’t in the previous 20 mph zone in my ward) to the council’s criteria or indeed the conversations I’d had with residents.

Greenwich using 1990s guidance

But after asking quite a lot of questions, I established that Greenwich had decided to apply a quite different set of criteria for placing speed humps when they introduced 20 mph zones.

Greenwich Council’s criteria was based on a 20 year old piece of Department for Transport guidance (Traffic Advisory Leaflet 9/99 in case you wanted to look it up) which suggested that speed humps were needed whenever 85th percentile speeds were greater than 24 mph. However, the council wasn’t even consistent in using this criteria, as it then decided that it made sense to place speed humps in the four roads where traffic speeds didn’t reach 24 mph for the quickest cars.

The effect of this hidden change in the council’s criteria for adding in speed humps has been to:

• Slow down the introduction of the 20 mph zones (as every zone becomes much more expensive due to the number of speed humps required – 220 are being constructed in 2017-18 alone).
• Cover the borough in speed humps which simply aren’t necessary to reduce the speeds of cars according to the council’s own published criteria or the government’s more recent guidance.
• Disrupt other forms of transport around the borough like cycling because it is harder to negotiate the inconsistent heights and widths of the speed humps.

I just want to confirm that as Leader of the Opposition, we supported 20 mph zones with minimal speed humps to enforce them. But I remain firmly of the opinion that the decision to introduce speed humps is a matter for residents on individual roads or sections of roads.

It may well be reasonable to question whether 20 mph zones like the one in Lewisham are effective, but Greenwich Council has completely ignored its own, democratically decided, policy in favour of a completely different set of criteria, which simply can’t be right.

I would also argue as I drive along the pot-holed, damaged road surfaces between the speed humps that maybe the council would be better advised to maintain the roads we have rather than spending the funds available on extra features.

Of course, maybe the potholes are the alternative to speed humps for a council which wants to slow traffic down – is this another hidden policy that Greenwich hasn’t told anyone about yet?

Spencer Drury is the Conservative councillor for Eltham North.

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