Average speed report from 1936

[David Stepney]

It might be worth mentioning that the Road Traffic Act of 1903 raised the speed limit of 14 mph imposed by the Locomotive Act 1896 to 20 mph on all roads. This was not altered until the Road Traffic Act 1930, which removed any apeed restriction on the basis that the previous speed limit was almost universally ignored. It was not until the 1934 act that the then minister of transport Leslie Hore-Belisha introduced the 30 mph limit in built up areas. During the Second World War, this was reduced to 20 mph during the hours of darkness due to the lighting restrictions imposed.

Do we go round in circles? And, if so, why do we need to build 1000 hp monsters that do 0 to 60 in the twinkling of an eye?

[Denis Sweeney]

I understand the belief that reducing speed is safer but I do question the validity of the claim that a 20mph speed limit will improve air quality.
My modern, a 3 year old VW Tiguan and my not so modern a 22 year old MGF can only run at 20mph in either 2nd or 3rd gears without their respective engines being distinctly uncomfortable and in both cases at much higher engine revs than they can both comfortably run at 30mph in 4th.
I may be wrong, but I would guess an engine running at significantly higher revs will emit greater emissions than it will running at lower revs regardless of speed of travel??

[Dave Mann]

I find our standard RN saloons can maintain an average of 30 mph provided we are not hindered by modern cars, for instance setting off at 0800 on a Sunday morning for the drive to Woolaton Park it would take us 2 hours whilst the return trip took 2.5 hours. The highest average speed I achieved was returning home from Falmouth 361 miles, it was a blistering hot day and initially the car was quite happy at 45 mph on the A30, however by the time I was at Exeter I was having to back off the throttle to keep down to 50 mph so at a refueling stop at Exeter I tightened the hand throttle friction pad. Onto M 5 with the hand throttle set for 50 mph , I usually refuel every 100 miles working on 35 mpg so I thought I should refuel at Strensham services (120 miles) and could only get 2 gallons in. I bottled out of negotiating spaghetti junction and left the M 5 at unction before. I completed the run in 9 hours 25 minutes including watering stops at 50 mpg.

[Ray White]

Perhaps this will put the cat among the Pigeons :

https://www.gbnews.com/lifestyle/uk-driv...nforceable

[Chris KC]

I understand the belief that reducing speed is safer but I do question the validity of the claim that a 20mph speed limit will improve air quality.
My modern, a 3 year old VW Tiguan and my not so modern a 22 year old MGF can only run at 20mph in either 2nd or 3rd gears without their respective engines being distinctly uncomfortable and in both cases at much higher engine revs than they can both comfortably run at 30mph in 4th.
I may be wrong, but I would guess an engine running at significantly higher revs will emit greater emissions than it will running at lower revs regardless of speed of travel??

Exactly. Several scientific studies have concluded there is a "sweet zone" of 30 - 50mph at which noise and emissions are minimised.

[Hugh Barnes]

In Cambridge, where we have 20mph zones in (some, not all?) side streets, the argument has been that a pedesrtian is more likely to survive a collision with a car at the lower speeds..

[Mike Costigan]

Has anyone investigated the increased likelihood of a pedestrian being hit because the driver was concentrating on keeping his car running at 20mph?

[Steve Jones]

Going back to the original post and the comment by Malcolm, this weekend we've been marshaling at the VSCC Herefordshire Trial. We live in North Yorkshire and drove down in the modern on Friday. That was 180 miles including a 20 mile diversion off the M5 and back to view a car near Pershore. The majority of the rest was motorway at 70 in cruise as much as possible. Return yesterday was 160 miles all but around 10 miles again on motorway at 70 in cruise as much as possible. The remaining 66 miles over the weekend were along B roads and narrow Herefordshire lanes where 20 mph can, sometimes, be too fast. According to the car, we averaged 41mph over the full weekend. Not that much faster, really, than in 1936 given the motorway mileage.

Steve

[Chris Garner]

Mike,
That's a very good point you raise. My car has a speed limiter but for those cars without one it can be distracting having to keep checking the speedometer, especially when required to keep to such a low speed as 20 mph. Even in a Seven it's difficult, especially when the speedo needle is probably waving all over the place!

[Chris KC]

In Cambridge, where we have 20mph zones in (some, not all?) side streets, the argument has been that a pedesrtian is more likely to survive a collision with a car at the lower speeds..

Exactly so Hugh - the chances of surviving an impact are dramatically improved if the speed is reduced by 30% (or even more for 90%...) However as others have said, 20mph on a good road actually requires greatly increased concentration on the speedo (and less on the road), and also rather increases the risk of the driver zoning out at the wheel through sheer boredom.

I could understand if it was done at peak times on busy high streets - but the allocation of zones does not (I cite Bedford's case) match risk. Nor does it need to be 24/7 - e.g. 20mph outside schools at certain times of day I can understand.