London speed limits make front page news

Ronnie Cohen, one of our regular contributors, wonders why it  will be easy to find the cash to reduce speed limits in London but has been impossible to convert them to metric.

It is rare for traffic speed limits to appear as the main exclusive headline in a major newspaper. However, proposed changes to speed limits on London roads made it to the front page of London’s Evening Standard newspaper on 24 July 2018 under the headline “Slow Down: New Limit for London” with an image of a 20 mph roundel in the middle of four short columns of text. Above the main headline was the banner text “C-Charge Zone first for change – but restriction will go city-wide from 2024”. This was their front page:

During the first phase of these changes, the Victoria Embankment, Millbank, Albert Embankment and Blackfriars Road will get the reduced speed limit by May 2020, when Mayor of London Sadiq Khan’s first term ends. The rest of changes will be introduced between next year and 2024. The proposals include:

  • 20 mph speed limits across 37 town centres to be implemented by the boroughs (if they agree to do so)
  • traffic-calming measures
  • speed cameras to enforce the lower 20 mph speed limits
  • redesign of dangerous junctions
  • safety measures on HGVs
  • buses fitted with automatic brakes

The purpose of these changes is to reduce road deaths and bring the number of road deaths down to zero by 2041. These plans are part of the Mayor’s Vision Zero initiative. New safety measures to reduce road deaths would surely be welcomed by everyone.

The Department for Transport (DfT) has consistently argued over many years that changing speed limits and other traffic signs to metric units would be too expensive and would divert resources from other parts of the transport budget. However, there is no suggestion that the Vision Zero initiative will do that. Many new 20 mph speed limit signs and road markings have already been introduced across London over the last few years but nobody complains about their cost or argues that they divert money from other areas. Not even the DfT makes these claims about these 20 mph signs and road markings.

When we compare the attitude of the DfT towards metrication with its attitude towards the installation of large numbers of 20 mph road signs and markings across many parts of London, we can see a lack of consistency in their arguments about transport budgets. Both involve spending money, which has to come from somewhere. Why does the DfT insist that metrication is too expensive and diverts money from other parts of the transport budget but does not apply the same logic to changing speed limits across London to 20 mph?

There is lack of political will to metricate British road signs and the DfT has been making excuses for years to avoid change. However, if kilometres were allowed to be used on British road for lower speed limits and made with distinctive signs, the transport authorities would have a greater choice of lower speed limits. With miles, they just have the 20 mph option. If they used kilometres, they could use two reasonable alternatives to the 20 mph limit: 30 km/h (19 mph) and 40 km/h (25 mph). Taking advantage of the opportunity to switch to lower speed limits to introduce kilometres instead of introduce new 20 mph signs and road markings would require no additional government spending. The DfT and our politicians just need the political will to authorise kilometres in the TSRGD. That’s all it would take.

10 thoughts on “London speed limits make front page news”

  1. As Ronnie points out, changing London’s speed limits to metric would significantly reduce the cost of the proposals. “30” ceases to mean 30 mph and becomes 30 km/h, that is 19 mph. Job done. But of course the reluctance to make the metric changeover is not really about money after all.


  2. As I have said a number of times before, DfT could just change the law from miles per hour to km/h and leave the signs as they are. It would then be up to whomsoever wanted to put the speed limits back up to find the money to do so.


  3. The biggest logical hurdle to converting to metric speed limits is that for safety reasons all such signs should be changed overnight (or over a weekend). And there will be arguments in various jurisdictions about which “nearby” speed limit in km/h should replace the existing mph limits will have to be resolved. However, a clear will to convert can drive deciders to pick a reasonable new speed limit.

    As for quick conversion of all speed limit signs, wouldn’t sticky decals solve that problem?


  4. When driving into busy town centres I always take all speed limits to be in world standard km/h it’s easy, works every time and zero cost. There is simply no need for more outdated expensive 20 mph signage.
    Most U.K. vehicles have world standard km/h shown on their speedometers.


  5. Ezra Steinberg 2018-08-09 at 19:13
    In a word, no. It would however solve the signpost version but as ‘they’ are looking for excuses not to do the job at all decals are definitely off the menu.
    One of the ever growing problems with changing UK speed limits is the practice of building them into the roads with different colour ‘tarmac’. I have long suspected the reason for this is to make them difficult to change, where just painting them would have made it difficult enough.


  6. SUGGESTION: In some areas of the UK residents have put stickers on the side of their dustbins usually saying: ’30 mph’. [The bins are put out on the pavement – to help drivers get the message ‘to slow down’ and ‘observe the speed limit’ – in urban areas].
    NOW A REQUEST: Is there a company/business which produces cheap, suitable stickers, that interested members of the public can put on the side of their bins that say ’30 km/h’ ?
    The sign/sticker could even show the ’30 km/h’ in a red circle.


  7. @BrianAC

    There is a major problem with just changing the law to make MPH into km/h for speed limits… I would never consider myself a ‘petrolhead’ but I have a strong belief that making speed limits too low can be just as dangerous as making them too high, speed limit enforcement in the UK already has a very bad reputation in many circles and the number of people who would just ignore lower limits, hence causing danger to those who insist on sticking to them, would in my view be an unnecessary risk.


    I’m also not convined that an overnight change would be necessary if properly planned and managed. Despite what the pro-Imperial lobby love to try to convince us, people are not ‘stupid’ and with the proper campaign in place there is no reason why dual speed limit signs could not be in place for several weeks during a changeover and the legal requirements for accuracy of speedometers might be of help with the minor differences in speed limit both during and after a changeover.

    The law allows speedometers to over-read up to 10% and motor manufacturers seem to err on the side of caution which means a vehicle being driven at an apparent 70 MPH might actually only be travelling at 63 MPH but rarely actually at 70. You can test this both with speed apps on modern mobile phones (despite what was said years ago, these are actually now quite accurate) and the roadside signs that often flash up speeds (if you know the location of some of these signs you can use the two to get a good picture of how inaccurate your speedo actually is). Because of this you could pick a new speed limit up to 10% higher than the current maximum and those drivers who already obey the law would likely still be within that speed limit; those sticking to a 120 km/h speed limit on a motorway would unlikely to be breaking the original 70 MPH limit.

    That said, there are lobby groups who would strongly object to ANY speed limit increase regardless of unit being used and that in itself adds an extra complication to the task.


  8. This is a good idea and a clever way to save money, but it would involve the local authorities taking stock of where all their 30 and 40 mph signs are for them to be recycled as 30 and 40 km/h. I don’t know whether the Irish made use of this facility at all during their changeover in 2005, but they must have a very good template for their changeover and perhaps a report on how it was done. Perhaps this would be a useful basis for the UK to consider.


  9. @derekp:

    It might come as a surprise, but London ≠ UK. Unless we want to end up with enclaves surrounded by NI-style unit change signs, which IMO would make the muddle even harder to shift, advocate doing it for the entire nation/ country at roughly the same time or not at all. It’s pretty clear that this is just a sop anyway and some of the motoring lobby have dubbed it ‘Zero Vision’—most motor traffic in London already struggles to attain the heady heights of 30 km/h and the police force mostly declines to enforce breaches, hence reliance on limited number of undoubtedly costly cameras. AFAIK, there is Zero Evidence that it shall have the supposed effect. So it’s not about money or speed and it’s probably not about deaths, either.

    Likewise, if London alone does push ahead with changing all its ‘30’ signs to ‘20’ then we should insist that they keep them when the whole UK is later upgraded to km/h as a Zero Cost metrication or fund any backsliding to 30 km/h themselves and explain this to their taxpayers. As Maggie Thatcher always got wrong: the UK public sector never runs out of other people’s money to waste!


    Also has the advantage that were ARM to try vandalising them, the private owners would be more likely to protect their own personal property… My vinyl cutter is broken at the moment, else I’d offer to run a few off gratis. If you can provide the artwork and specify colours, material & dimensions (millimetres, of course) then most signmakers will make them bespoke with economies of scale for increasing quantity. Put me down for a couple!


    English DMRB gibberish unit ‘words’ added by the subtitle pixie:


  10. Check those “Police Car Chase” clips on YouTube:
    Speed given in mph.
    Distance travelled in metres.
    Mishmash UK; hate it and leave it.
    Jack, the Japan Alps Brit


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