Do we need speed limits?

[Martin Cassini]

No, I think people are best left to judge for themselves according to context and commonsense. There's plenty more to say about this, but I wanted to kick something off. These photos say it all.

[Martin Cassini]

Re your point about timid drivers, one of the things I advocate is phasing in an advanced driving test, which would mean that drivers who weren't up to scratch would have to unlearn bad habits, learn good ones, or die out. On our current unfit roads, we are plagued by priority rules that force us to act against our better nature and judgement. We must submit to lights dictating our every move and telling us when to stop and go. In the FiT scenario, when people are free of external controls and free to use commonsense to act according to context, they relax. My hunch is that free drivers will gain confidence, act and interact better.

In Montana, the period of lowest average speeds and fewest accidents was when their were no speed limits. As traffic researcher, Chad Dornsife, wrote, "The desired safety effect of speed limits is achieved by removing them." In the same way that I push for live trials to test junction performance and safety with and without lights, so I would like to conduct a scientific study of the benefits or otherwise of speed limits.

[Mark brindle]

ive come across uses of speed control in other countries - easy things we can do in the uk..
in portugal they have places with radar controlled traffic lights. If you go past a certain speed then the lights go red ahead of you to penalise you.. so you go slower through the town or the specific area where there may be a need to keep speed down.
IN australia they have 20 mph limits near schools, but this speed limit only applies during certain times of day and not all the time as we have in the uk. so at 3am or 7am or 10pm when its not school time you can go faster as the need for speed control at those time is not necessary.
so more intelligence in the rule base is what id like to see.
In germany they have no limits on autobahns and drivers go fast. i dont know the traffic statistics regarding fatalities etc to compare against need for 70mph limit on motoways in uk. I guess these stats are available..?
I think 70mph is too slow for modern cars with modern abs and alert drivers during good visibility and weather and majority of traffic on uk motorways is well above 70mph. variable speed limits on roads like m25 in theory work, as these are based on traffic flow models which try to avoid queues building up by limiting groups of cars getting to a congested area too quickly, and with onslip lights controlling extra cars getting onto the road. these are needed when the bandwidth of the road is not sufficient at peak time, but not all the time..
As an ex networking engineer ive had to do lots of traffic modelling for large scale networks which operate in some way similar to road networks. the backbone of the network needs to have sufficient capacity to handle the incoming and exiting traffic and so it is scaled accordingly. this would equate to having many more lanes on our backbone motorways, and higher speed limits to get traffic moving along it quicker - but once you get an overloaded network you cant get away from it without upgrading the backbone..thats a different thread really, but you can get more capacity out of the existing network by increasing ability to move traffic on, over and out of the network - and increasing speed limit would alleviate it somewhat on a purely mathematical basis. but you still dont remove congestion at peak time if you really are over subscribed with traffic.

[Martin Cassini]

Some good material here. The relationship between capacity and volume ... My hunch has always been that natural flow maximises efficiency, whatever the restrictions on the network. The theory of spontaneous order states that the more complex the "ballet" of human movement, the less useful are attempts to control it. Think of a skateboard park, where teens of all stripes merge in harmony. If traffic is like liquid, it will find its optimum dispersal route by itself. Volume can be a drama, but volume + controls = crisis. A mathematician I met recently echoed some of this: he said that external control interrupts optimal flow, from traffic to telephony.

[Ian Perry]

YES!!

That's a simple one word answer that I will now explain. The A55 in north Wales is just one example where a speed limit of just 50mph along much of the road doesn't not fit the road design, but is essential. If you are not aware of this road (made famous by the local Chief Constables rigorous enforcement), use Google Earth to zoom in on Abergele. You will see a fast dual carriageway where motorists can safely travel at speeds of 100 mph or more. Now I am not really bothered about the CO2 but I am concerned about the extra PM10 higher speeds produce (WHO - biggest threat to human health), the extra NOISE! This recently built road passes close to homes, and although homes can be insulated against noise, streets and gardens cannot - although barriers as found in the Netherlands can help to an extent, but are expensive, energy and material intensive and not visually desirable.


At the other extreme, the country road (single track with passing spaces). The limit in the UK is typically 60mph. I have driven a 3.5 tonne Royal Mail van on one use lane at 60mph and been overtaken! The theory being that you can always squeeze by an oncoming vehicle and that there will never be a cyclist or pedestrian... thus few dare to walk on these lanes.

If the 60mph speed limit was removed, people would continue to drive as fast as possible with the danger and noise that this brings. Speed limits on these roads do need reducing as they do influence people behaviour. For those lanes where pedestrians and cyclists are to be most encouraged, the speed limit must be set at 20mph. This is not so much about having speed limits to enforce, but about trying to get people to think...

[Stefan Langeveld]

One must read the Safe Speed site. The research and arguments destroy the speed limit case. It boils down to: the safe speed (range) is always dependent on the situation, never on fixed limits.
(Author Paul Smith curiously advocated sensible limits, mainly to help inexperienced drivers - I disagree)
So: basically no limits but
- much improved training - we must find ways to raise the skill level, a course for the general public that won't cost too much money or time. Learn how to drive safely instead , not how to apply the rules.
- police on the road to spot and warn/punish rogue drivers
- limits to reduce annoyance to residents, especially at night. (this is an unresolved point: empty roads invite high speed)

If you seriously want to set limits on a country road, you must place signs before and after every bend or narrowing (or 2 , or 3, counting down). Or, if that's too expensive or difficult: set a ridiculously low limit for the whole stretch. Or a dangerously high limit. Make your choice.

[Martin Cassini]

Thanks, Stefan. Seems to me that disturbance to residents could be overcome through psychological traffic calming expressed through good design.

Stefan Langeveld said:

One must read the Safe Speed site. The research and arguments destroy the speed limit case. It boils down to: the safe speed (range) is always dependent on the situation, never on fixed limits.
(Author Paul Smith curiously advocated sensible limits, mainly to help inexperienced drivers - I disagree)
So: basically no limits but
- much improved training - we must find ways to raise the skill level, a course for the general public that won't cost too much money or time. Learn how to drive safely instead, not how to apply the rules.
- police on the road to spot and warn/punish rogue drivers
- limits to reduce annoyance to residents, especially at night. (This is an unresolved point: empty roads invite high speed)

If you seriously want to set limits on a country road, you must place signs before and after every bend or narrowing (or 2 , or 3, counting down). Or, if that's too expensive or difficult: set a ridiculously low limit for the whole stretch. Or a dangerously high limit. Make your choice.

[Stefan Langeveld]

" psychological traffic calming" : Indeed, that's the work of David Engwicht (Mental Speed Bumps , Placemaking and more). Residents and shopkeepers must do exterior decorating, see and use the streets as corridors and squares as plazas. David has shown this makes all the difference: drivers' behaviour changes completely. (He notes that Shared Space does not attract, stimulate the general public, it's too top-down. I agree)
Unfortunately the authorities will not give up their power to design and construct the so-called public space.
For a start, residents should propose, negotiate and work at placemaking instead of demanding speed bumps.
This will be a long struggle, and a new political party is needed to support these ideas.

[Martin Cassini]

Agree, although residents and shopkeepers should see roads not as corridors, which is how they are conventionally viewed by traffic engineers, but rather as "living room" ...

Stefan Langeveld said:

" psychological traffic calming" : Indeed, that's the work of David Engwicht (Mental Speed Bumps , Placemaking and more). Residents and shopkeepers must do exterior decorating, see and use the streets as corridors and squares as plazas. David has shown this makes all the difference: drivers' behaviour changes completely. (He notes that Shared Space does not attract, stimulate the general public, it's too top-down. I agree)
Unfortunately the authorities will not give up their power to design and construct the so-called public space.
For a start, residents should propose, negotiate and work at placemaking instead of demanding speed bumps.
This will be a long struggle, and a new political party is needed to support these ideas.

[Stefan Langeveld]

Extension of my reply ; a longer (but readable i pretend) article against the 'speed kills' idea, which is the basis for speed limits and enforcement. Most of it you'll find on SafeSpeed.org and other sites, but it's always right to line up a collection of arguments.
Web version

Main argument:
Two types of speeding - please don't mix
Type I
Every situation sets an appropriate or safe speed range.
This is what good handbooks and instructors tell us, and what nearly all drivers do.
The situation includes road, vehicles, people, weather, your driving skills (these can be detailed into a long list).
All this results in a preferred, appropriate speed and direction.
Like: 'Here and now my speed should be 35-50 km/h'.

Type II
The speed limit is an upper limit for an area or road . This is what the authorities tell us.
It is at best an extremely poor attempt to guide drivers.
But if compared to the safe speed rule (type I), it is even dangerous and unacceptable.

The two types compared
Above the limit? You may drive at an appropriate (safe) speed or not. Below the limit: the same. An inappropriate speed may be above or below the limit.
Only an unsafe speed (too slow, too fast) can cause accidents.
An excess speed in itself does not cause accidents. This is indicated by the fact that half of us speed in excess day in year out (read 'them' if you don't drive).

Conclusion: there is no logical relation between the two. They can occur together (unsafe speed above limit) and the authorities highlight this to make their case.

The theory lumps the two types of speeding into one. It tables inappropriate speeds as a contributory factor then uses the amount of excessive speed to justify strong action.

[Martin Cassini]

Does this constitute more evidence for the case against speed cameras?

[phunksta]

I don't know if this adds to or subtracts from the debate - but here we go anyway...

An observation from spending a lot of time on the roads in the past week: There are far too many different forms of road instruction for the same factor of 'driver intelligence' i.e. the observations required to safely pilot a car.

For example - No stopping/parking/waiting: Double yellow lines, Double red lines, Single yellow lines, Single white line, Zigzags, Roadside signs, lettered signs, no parking signs, clamping signs

Another - speed: Speed limit signs, temporary speed limit signs, SLOW signs painted on the road, speed campaign signs, Speed camera warning signs, speed cameras, mobile speed scamera vans

Another - no overtaking: Double white lines, single white lines (?), striped areas/reservations (multiple meanings), no overtaking (red car black car) signs, 'no overtaking' lettered signs

So given all of this 'input', and given that it is not always consistently applied - both in single sites and over multiple sites across the country - how is a driver to determine what the 'correct' inputs are?
Are drivers suffering from 'information overload'?

What I would like to see is a clear and consistent set of road marking which give to me, as a driver, the information I need. In terms of speed that is 'for your vehicle, you should be travelling between x and y MPH'.
That should then continue to the other pieces of information; where I can stop, overtake, park etc.

[Martin Cassini]

Broadly agree. As I often scream (silently or otherwise), we face a forest of instructional signs, BUT WHERE ARE THE DIRECTIONAL SIGNS when we need them!? Inconsistency and blame - these are the perverse pillars upon which our traffic control system is based. Nothing is left to commonsense and context. All is prescription and coercion. You could be gliding along an empty road at a completely appropriate speed and suddenly see a camera. Arrggh! What's the limit? [At the very least, cameras should have the relevant limit shown on the camera pole.] What speed am I doing? You take your eyes off the road to look ... Bus lanes - within a few feet of each other they can change from 24-hour to peak hours only and back again. The worst kind of parenting is inconsistent - permissive one minute, angry the next. That's our traffic control system. Malevolent.