50 MPH Speed limit.

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Dan B

Disengaged member
Source - Physics - kinetic energy of an object is directly proportional to the square of its speed.

Hit a solid object (parked car, lamp post, wall etc.) at 20mph not good - at 40mph the energy has squared -much much worse - head injury could prove fatal.

So how many lives would it save?
 

marinyork

Resting in suspended Animation
Location
Logopolis
So how many lives would it save?

Turn bikes into flintstone cars.
 

Crankarm

Guru
Location
Nr Cambridge
These 50mph speed limit proposals seem to be by people who have never driven a car before, let alone on a motorway. When you have driven a car for a number of years then you will come to realise that a 50mph speed limit on a motorway in normal conditions is silly, have a 50mph speed limit in fog or heavy rain or when there's roadworks (which is often what they have in such conditions) but on a clear dry day there's no need for a reduced speed limit.

+1.

I am going to prejudge the findings of the M5 crash. What ever the weather conditions - fog or whether smoke from the firework display played a contributing cause, whether it was awful weather generally, etc, etc, all excuses, the bottom line is that the vehicles were travelling too quickly for conditions to be able to stop safely and likley too close to the vehicle in front eg tailgating. Period.

We all see it when we are driving or are passengers in vehicles on the motorways. Sadly when coupled with bad weather it is a certainty that people will die. 2,500 people killed every year on our roads. The motorways are some of the safest roads, were are told.

What is needed is a mandatory reduction to 50mph when raining or the weather is poor as in France (100kmh/62mph) and even less if very poor which could be given by motorway signalling system. The other thing that is needed is average speed cameras across the whole of the motorway and arterial road networks. There are average speed cameras on the A14 between Huntingdon and Cambridge which have made a massive improvement in road safety but none the less it can still be a terrifying road to drive especially with all the trucks that use it who don't give a fig about pulling out who take 10 miles to pass the truck in front or driving 18 hours and falling asleep at the wheel and careering across the central reservation or taking out a petrol station - yes this almost happened but fortunately a quick thinking employee switched the pumps off before it hit which brings me to my third thing. Much more goods has to be moved by rail cutting the huge amount of freight on the roads which just doesn't need to use the roads eg Harwich to Manchester/Liverpool. But government won't do this as it wants the duty from fuel and road fund license fees from HGVS which if goods went by rail would presumably mean they would lose.

The current speed limits are fine it is just enforcing them that is the problem. Catching, fining and re-educating bad and dangerous drivers must be made a priority. The fines levied could pay for any punative action or re-education. Alternatively just ban them from the roads altogether :thumbsup: .
 

I_S

Active Member
[QUOTE 1604725"]
"not good" "much much worse" "could prove fatal" - not really terms upheld as sufficient to change national policy are they?

What you need to do is to investigate the factors involved with cycling incidents (whether you focus on KSIs is up to you). When you've done that you'll have some idea of the proportion that the element of speed influences. Then, if it's an substantial enough factor, you can investigate (properly) the change that a reduction in the speed limit for cycles would bring. I'd be interested in your conclusions.

I suspect you'll find that cycle speed is not a big factor, and it's more to do with the speed/size/etc of the big metal machine that runs you down.
[/quote]

My position is I'm opposed to a 50mph limit for cars and would welcome an increase from 70 to 80mph on motorways. The OP wants cars to be limited in law to 50mph on safety grounds.

Yet here http://www.cyclechat..._1#entry1901557 the OP talks of cycling at 40mph.

The thought of a front wheel puncture, collision, mechanical failure etc at 40mph on a bicycle doesn't bear thinking about. Yet 51mph in a modern car is too dangerous for the OP?
 

Arch

Married to Night Train
Location
Salford, UK
Yet here http://www.cyclechat..._1#entry1901557 the OP talks of cycling at 40mph.

The thought of a front wheel puncture, collision, mechanical failure etc at 40mph on a bicycle doesn't bear thinking about. Yet 51mph in a modern car is too dangerous for the OP?

A cyclist doing 40, who comes off, for whatever reason, is likely to kill themselves only. A driver driving too fast for the conditions, whatever they are, and whatever speed that is, can kill plenty of others, both their own passengers and people in other cars.

Also, the benefits of being 'in a modern car' are great for the people in it. Not so great for the people outside them, if it lulls drivers into a false sense of security. I gather that when seatbelts were made compulsory, car occupant deaths and injuries went down, but pedestrian and cyclist deaths and injuries rose.

I met a chap once, who ranted that recumbents were dangerous because of the pointy chainring up front. When it was pointed out that they weren't as dangerous as cars, for example, he said (and I quote) "But if you get hit by a car, you just roll off". He seriously thought being hit by a car was no big deal. We're sold the idea that modern cars are safe, but they're only safe if you're in a position to benefit from it. Those airbags don't do you much good when you're on fire.
 

I_S

Active Member
[QUOTE 1604731"]
I'd prefer it if you took notice of my post and provided the necessary information to support your suggestion that slowing bikes down will stop drivers killing cyclists.
[/quote]

Where did I say that slowing bikes would stop drivers killing cyclists?

Please don't make things up.
 

I_S

Active Member
[QUOTE 1604733"]
I'm not. The main killers of cyclists are drivers. You have suggested that slowing cyclists down will improve safety. You need to show the link...
[/quote]

You have attributed to me a statement that I did not make: here it is again verbatim "slowing bikes down will stop drivers killing cyclists" posted today at 16:01:23.


You have had the opportunity to consider your position - the statement you attribute to me is fictitious.


Then at 16:58 you reply that you didn't make the statement up.


Your evidential reasoning appears flawed - the trail is there for all to see. Please don't make up statements on my behalf and present them against me.
 

Archie_tect

De Skieven Architek... aka Penfold + Horace
Location
Northumberland
slowing bikes down will stop drivers killing cyclists

I can't see a connection, how would it work?
 

albion

Guru
Location
South Tyneside
I went along an uphill windy dual carriageway today. A route very new to me.The inevitable HGV's and speeding drivers approaching them too fast certainly caused more than some friction.I'd hate to be a cyclist with that as a daily route. An accident certainly waiting to happen.A 50mph limit may have helped a little.
 

I_S

Active Member
[QUOTE 1604737"]
Apologies for the diversion. Now, back to topic...

You suggest that limiting speeds for cyclists will reduce deaths. Drivers are the biggest killers of cyclists.

Please explain how slowing cyclists down will stop drivers killing them.

if you think about it you'll see that it wouldn't bring the result you hope for.
[/quote]

Apologies accepted .

Slowing down cyclists won't stop drivers killing them, I never said so. My point is that if a modern car is limited to 50mph as the OP proposes there's an irony when the OP talks of cycling at 40mph..

I've cycled over 5000 miles in the last year and been struck / knocked off whilst commuting at least 6 times and received hospital treatment as a consequence. Two years ago I required an ambulance, orthopedic surgery + a plate after another collision. On every occasion the vehicles have been driven at about 20mph but not paying attention, mostly on roundabouts / junctions in heavy slow moving traffic. One driver was prosecuted, no further action for two others. The enemy was always bad driving - never speed.

Where I live the local authority keep adding yellow boxes and replacing roundabouts with badly sequenced traffic lights - drivers are then very frustrated as journey times increase for no apparent reason and average speeds drop. In my experience it was rare to see drivers jumping red lights perhaps 5 years ago - last night I watched four cars go through on red as I cycled on green. This is an unintentional consequence of traffic calming/management. Too many painted road markings trap vehicles in the wrong lane etc.. My take is that a few years ago when the traffic flowed at 30mph vehicles didn't bother putting two wheels in the cycle lane and commuting was safer.

As bicycles and pedestrians aren't allowed on motorways and the accidents per mile are lower than other roads why lower the speed limit? In towns the anti vehicle measures impact negatively on cyclists and in my experience increase danger .

In the last year I've driven cars and motorcycles in ten countries. The Dutch cycle lanes I've seen are excellent, and traveling leaglly on the autobahn at more than twice the UK limit was very straightforward in light traffic - a better standard of driving was evident.

Reducing the limit seems to increase frustration and that increases danger.
 

subaqua

What’s the point
Location
Leytonstone
ok now imagine how badly you would have been injured had the driver been driving faster than 20mph.
speed and mass are both factors in the equation . Greg collins illustrated it succinctly by using a bullet from a gun. do the speed calcs there and tell me which is safer a fast bullet or a slow bullet.


that doesn't excuse people twisting posts though, something that is happening a little too often here IMVHO.
 

I_S

Active Member
ok now imagine how badly you would have been injured had the driver been driving faster than 20mph.
speed and mass are both factors in the equation . Greg collins illustrated it succinctly by using a bullet from a gun. do the speed calcs there and tell me which is safer a fast bullet or a slow bullet.


that doesn't excuse people twisting posts though, something that is happening a little too often here IMVHO.

Agree, as I've already posted doubling speed means energy squares. On my commute on rainy evening the traffic often crawls to a standstill. Every junction has trapped cars in the wrong places, horns going etc. Motorists who intend to turn left pull into the cycle lane a huge distance before junctions and block them. Every advance stop box has cars in it. Then you see desperate moves through red lights. A few years ago the traffic flowed better and it was calmer at junctions where danger lurks.
 

Davidc

Guru
Location
Somerset UK
One aspect of speed not mentioned so far is that in heavy traffic reducing speeds reduces jouney times. That's why the variable speed limit systems on the M42, M25 etc. work. High speeds (and limits) only reduce jouney times on empty roads.

The evidence for this counter-intuitive result is huge and not sensibly disputable. I'd be interested to know what the effect of the OP's suggestion would be on total times for all jouneys. The small increase in times for trips when traffic is light might be more than compensated by shorter times in heavy traffic when far more people would benefit.

The piece of M5 where the collision happened (about a mile from where I'm sitting) often has 5 mph maximum traffic both ways most of the time from Friday afternoon to Sunday night in the Summer, with average speeds between Bristol and Exeter of less than 15 mph (5 hours for 70 miles). Perhaps a lower limit would benefit drivers then as well as reducing death and injury when things go wrong?

I'll wait for the police to report their conclusions on last week's events, but will nonetheless guess that the cause was a perfect storm of a number of contributory factors rather than a single culprit.
 
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