Are lower blanket limits the answer for Witney?

Speed and speed limits are always controversial.  They get a massive emotional response.  Stand by the side of the road and almost everyone feels angry about ‘those bloody speeding drivers’.  

Likewise, over the last few years 20mph limits have become an ideological rallying point for some groups – an article of faith, almost. 

The problem is that lower limits are a superficially attractive solution, but a 20mph limit and other lowered limits aren’t the way to get people driving slowly and safely in Witney.  In fact, they’re likely to have almost the opposite effect.


  • Lower limits, particularly 20mph limits, are an ideological rather than a practical road safety tool
  • Lower speed limits are an ineffective tool for real world speed reduction
  • Oxford’s 20mph limit led to barely noticeable reductions in vehicle speeds – with speeds on some roads increasing
  • These limits will be contrary to government advice in DfT Circular 01/2013
  • Ultra-low limits lead to frustration overtakes, tailgating and driver aggression – with the most compliant and vulnerable road users suffering
  • Lower limits do not lead to increased cycling and walking
  • The negligible road safety and ‘active travel’ returns will not come close to justifying the cost of the limits

Is there a problem with speed-related accidents in the town?

Witney’s accident record, fortunately as low as it is, shows there is a minimal problem with speed in excess of a limit – at least as a cause of crashes.  Finding crashes caused by a sober, drug-free driver in their own car (rather than a stolen vehicle) is a challenge.  And a 20mph limit or other lowered limit will have no impact on drivers like these.  And, nationally, we know that speed in excess of a limit is one of several factors – not the sole factor – in just over 7% of crashes (Department for Transport).

What is speeding?

‘Speeding’ is a loose term.  There is a huge difference between ‘excess speed’ – speed over of a speed limit – and driving too fast for the conditions. The two are often conflated, but the Police treat them as two different causes on their Stats 19 accident investigation forms.

Driving too fast for the conditions (which can easily be lower than the speed limit) is potentially dangerous as well as disturbing for other road users.  Driving faster than a speed limit is a legal compliance issue, not a road safety one.  

After all, how can 30mph on the same stretch of road be perfectly safe and legal on one day yet criminal and dangerously fast on the same road the next day when the limit is lowered?  And any driver would still be able to drive perfectly safely – if not legally – if their speedo broke.

At the same time, millions of drivers exceed speed limits every day with no ill effects.  Recently 23,500 people exceeded a newly imposed 20mph speed limit in Plymouth in an 8 week test period with not a single accident. Department for Transport figures show that 84% of drivers exceed 20mph limits daily with no ill effects.

Speed limits are not physical absolutes in the way water boiling at 100˚ is, yet we treat them as though they are.  Nothing happens when a driver exceeds a limit, except in law.  The argument is then ‘ah, but you’re more likely to lose control/not have enough time to react/hit something harder…’ – these are all true for driving too fast for conditions but not for exceeding a limit.

Do people think drivers are going too fast?

Pretty much everyone – me included – is annoyed with people driving too fast even though they’re often still within the speed limit.  So, given there’s no history of speed-related accidents, lowering the limit isn’t an objective decision – it’s an emotional and ideological one. 

What’s going to make people in Witney feel as though traffic speeds are ‘right’?

Will a 20 limit work?

Government advice and studies make it clear that 20mph limits won’t reduce crashes.  

“The evidence available to date (for 20mph limits) shows no significant change in the short term in collisions and casualties in the majority of the case studies.”  

This mirrors studies elsewhere in the UK that have shown no change in crashes because of 20mph limits.

(source: DfT Atkins and Maher – 20-mph-speed-limits-on-roads)

But will it actually make people drive slower? 

Again, that DfT study referenced above is useful.  It says:

“Journey speed analysis shows that the median speed [after the imposition of a 20mph limit] has fallen by 0.7mph in residential areas and 0.9mph in city centre areas.”  

This matches more recent evidence in Oxford showing an average speed reduction of 0.8mph where the city spent £300,000 reducing 30 limits to 20.

In other words, yes, a 20mph limit may make people drive slower – between 0.7mph and 0.9mph.  Expensive, barely measurable and hardly significant but a significant waste of budget that could be spent elsewhere.  

Don’t ask why – just do as you’re told

‘Setting Local Speed Limits’ (DfT Circular 01/2013) advises that 20mph limits are most appropriate where the mean speed of traffic is already at or below 24mph.  This is already a de facto reduction from the way we used to set limits using the 85th percentile speed.  On many of the proposed roads in Witney, speeds are higher than this. It is unlikely that lowering the limit will work in these cases.

There is likely to be massive non-compliance with the new limits.  significant non-compliance, in turn, lessens respect for other limits, meaning drivers are more likely to drive faster.

Will a 20 limit assuage people’s annoyance and anger at ’speeding drivers’ and thus be electorally popular?  

Sadly not. Atkins and Maher again: 

“The majority of resident (about two-thirds) and non-resident drivers (just over half) have not noticed a reduction in the speed of vehicles, and do not perceive there to be fewer vehicles driving at excessive speeds for the area.”

So we’ll have more sign clutter, probably more white paint and spend more money, accidents won’t decrease, speeds won’t fall and the limits won’t even stop people feeling angry and annoyed. That’s not a win for either the County Council, councillors hoping to leverage the new limits for re-election or residents.

Will it increase walking and cycling numbers?

It’s hard to say without knowing what percentage of journeys in Witney are already taken on foot or by bike (we asked OCC for the data and also the targets for the increases the limits are intended to generate but we didn’t receive it).  However, we know that between 2% and 3% of journeys are made by cycle and, from Atkins and Maher, that :

“Amongst residents, in general – Section 9.2 shows that the majority of residents (69%) agree that 20mph limits have been beneficial for walking and cycling. In most cases, this has not been translated into an increase in actual levels of walking and cycling…”

The report goes on to show that a self-reported “5% said that they are walking more, and 2% said that they are cycling more. Applying a 95% confidence interval suggests that the true range (in the wider population) varies from 4% to 6% for walking, and 0.5% to 3.5% for cycling”

This is, however, self-reported. It seems reasonable to assume that 20mph limits will have a minimal effect on already sadly low-use modes.  

As a 120m+ per week year-round commuter cyclist, 20mph limits have no impact whatsoever on my propensity to ride. In fact, because it often results in additional aggression from drivers (I had my first ‘get on the f**king cyclepath!’ after the first Witney 20mph limits went in), I worry it’s likely to have the opposite effect.

The daily driver

This hardly constitutes value for money and means that the vast majority of people will be significantly inconvenienced in the hope of increasing a vanishingly small, but vocal, minority. 

Also, lower limits are proposed along roads where cycle and walking traffic are already significantly separated from vehicles; Deer Park, Burford Road, Ducklington Lane and Jubilee Way, for example.  Lowering the already low limits here will sadly have minimal to no effect on promoting cycling or walking.

Will it improve the environment?

Bellefleur and Gagnon 2011, makes it clear that lower speeds increase vehicle emissions – they are most efficient around 80kph.  Whilst diesel cars may be slightly cleaner at low speeds, emissions from petrol car NOx increases by nearly 8% at 20mph. 

Why won’t a 20 limit work?

Speed limits are extraordinarily ineffective at reducing vehicle speeds – in fact, it’s a job they were never intended to do. 

Limits were designed to reflect the behaviour of the law-abiding majority (an antisocial minority will exceed them no matter what) which is why they are ineffective at making people drive slower when they are lowered below the ‘natural’ speed for a road.  

Think about it – were you driving precisely at 30 as you went past the 30mph signs in Curbridge this morning?  If you’ve driven down Burford Hill or up Corn Street, were you sticking exactly to 20mph?  Limits are legal, not physical, absolutes.

Even Department for Transport Circular 01/2013, probably the most hardline speed limit setting document yet, states “Speed limits should be evidence-led and self-explaining…”

Where Witney’s roads support a speed of around 20mph – or less – most people are already driving at that speed.  Where they support 30, 40 or 50, they’re driving at around 30, 40 or 50.

Witney’s roads – apart from narrow residential streets where cars are almost universally running at sub-20mph anyway – don’t make sense at 20mph.  The alignment is too open and wide with broad views, leading to 30, 40 or 50 as a natural speed rather than 20, 30 or 40. Where roads are narrow, most vehicles are already driving well below 30 and those drivers driving too fast won’t be deterred by a 20mph limit.  And where the limits are higher – on the edge of town – lowering 40s to 30 and 50s to 40 will have the same negligible effect.

The results of mechanistic thinking in road safety

It seems the arguments for the limits are a little self-contradictory. Limits are “designed to be self enforcing”. In other words, traffic will already be traveling at or below 20mph. If this is the case, it is difficult to see the need for a limit. Those drivers who push the limits of safe speeds in built-up areas will not be dissuaded by a limit. Those who do not will already be traveling slowly in any case.

Safe speeds vary constantly – up and down – from driver to driver and second to second.  Of course, that doesn’t give an excuse to rag through the centre of the town at 50mph, but neither – in my opinion – does it give either OCC the right to force a driver to drive at 20mph on a newly lowered road in clear, low-hazard conditions where 30 was apparently safe two weeks ago before the limit was imposed.  Likewise in the proposed 30 and 40 limits.

Making things worse – particularly for the law-abiding

At the same time, as someone who sticks to limits no matter how low, I’m tailgated, hooted, flashed and overtaken aggressively when I stick to existing 30 limits (Curbridge, for example, that used to a 40mph limit with far better compliance) let alone artificially low 20 limits like the lower half of Corn Street or Burford High Street.  That’s grim enough in a car – it’s terrifying on a motorcycle. 

Those overtakes are often opposite junctions, into the face of oncoming traffic and, recently on the wrong side of a traffic island.  It sounds counterintuitive, but limits that are too low are dangerous; they lead to aggressive, frustrated, angry driver behaviour.

Along roads like Curbridge Road or Woodstock Road, lined with junctions and driveways, frustration overtakes caused by drivers sticking to the new ultra-low limits will – in my view – result in serious crashes.

Are there downsides to ultra-low limits like the ones proposed for Witney?

They won’t work

A road has a ‘natural’ speed.  That’s why drivers are usually faster – even without a limit – on roads like Curbridge Road than they are on, say, Farmers Close. That’s because people match their speed to the way a road looks.  The more open, straight and clear – the faster they drive – and that’s OK.  There are fewer hazards and, crucially, better sightlines to spot them and space to avoid hazards.  Also,  the less ambiguity about right of way, whether something is a road or a pavement – the faster drivers go.  Introduce ambiguity – the sort you find in a shared space scheme –  and vehicle speeds fall dramatically.

Ultra-low limits are a distraction

Left turns for cyclists

Ultra-low limits are a distraction

Where a limit is considerably lower than the natural speed limit for the road is imposed, drivers need to devote greater levels of concentration to compliance rather than safety. In other words, they spend more time speedo-watching than looking for children running out, cyclists, other hazards and other vehicles.

Don’t believe me?  Drive from Bampton, through Witney, down the hill in Burford and back.  Get someone to sit with you and watch your speedo and note how often you exceed the limit, even by 1mph. Also, notice how much attention you need to invest in limit compliance because the limits are now too low for the roads.

That’s without even looking at the frequency with which limits change in the county.  

  • My nine mile ride from Bampton to Burford goes 30-60-30-60-40-30-40-60-30-60-40-60-30-20; a limit change almost every half mile. 
  • The six mile journey from Bampton to Witney goes 30-60-40-60-30-60-40-30-20; nine limit changes in six miles.  

Like paint-by-numbers, OCC”s ‘drive by numbers’ policy is a clumsy facsimile of the real thing.

It writes a cheque the County Council can’t cash

These lower limits leave the County Council creating an expectation and making a promise it can’t deliver on.  Once the limits are shown as being ineffective, people will start calling for urban-style calming and cameras.  

That means forests of signs, white lines, noise and pollution from vehicles over speed bumps and revving engines as people drive over them.  We also know from our own village and Brize that OCC doesn’t maintain traffic calming as it should, exacerbating the problem. For cameras, it means a focus on compliance over safety and a significant distraction effect.  

So what’s the answer?

Of course, 20mph and lower limits give the impression that ‘we’re doing something’.  And it’s easy to put signs up and think the problem is solved – but it won’t be.  In fact, if anything, it’ll be worse as drivers simply ignore the 20 limit as being too low and drive faster and more aggressively than they might have done before.

There’s actually not much we can do – at least, not with limits or even conventional calming. 

If the County Council wants to reduce speeds without signage clutter, the need for additional calming and enforcement, it would be worth investigating shared space schemes. If the evidence from continental Europe is correct, these schemes improve the urban environment, improve social cohesion and return streets to the people who live on them. Of course, they don’t hector drivers and don’t allow a minority of residents and perhaps even a few councillors  the gratifying sense of “Ha! We’re punishing those nasty drivers now!”, but they do work – with very few downsides.

Some links:  (this shows a 13km/h reduction in speed and 49 per cent reduction in casualty crashes)

It seems to me that the Council has a superb opportunity to improve Witney’s streets rather than make them uglier, at great expense, with seriously detrimental side effects and to very little purpose.


5 thoughts on “Are lower blanket limits the answer for Witney?

Add yours

  1. Couldn’t agree more. Burford 20mph speed limit is so distracting. Don’t think I ever did 30mph down the hill, due to parking, pedestrians etc, but watching the Speedo to make sure I’m not doing over 20mph, distracts attention and so is more dangerous than the original 30mph was.

    Liked by 1 person

    1. Absolutely. Burford hill is now first gear (more noise, more pollution – such as it is from modern cars) and nose-to-speedo to prevent going more than 20mph. It’s certainly not made crossing the road easier as drivers now don’t seem to see you.


  2. An excellent article setting out analytically what intuitively I feel. Shared spaces seem to me to work well and create less frustration as I find actually most people are polite and helpful to others when there’s clearly a need for voluntary cooperation. Frustration seems to me to arise when one feels someone else is taking away your freedom of action.

    I also agree from a pragmatic view. I can’t believe 20 mph limits will be enforceable all across town so they will simply create tension between those of us that try to comply and others who feel we’re in their way. Whatever enforcement is available would be far better focused on addressing known accident blackspots.

    I could add much more in support but you’ve already covered so much. Well done.

    Liked by 1 person

  3. An excellent post and I’m sure one that will cause some controversy. In Scotland they trialed such a scheme and because of its so called ‘success’ it has been implemented right across the borders. The phrase is ‘Coming to your neighbourhood soon’ I think, regardless of the evidence against it.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Blog at

Up ↑

%d bloggers like this: