Why are coaches permitted to drive at 70mph on the motorway (but banned from the third lane) whilst HGVs are restricted to 60mph (and held down to 56mph by the limiter)?
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Hi Duchess,
Very good question...
I don't think there is a good technical reason for this. Coaches, usually, have one steered axle, and one double tyred drive axle. I would estimate that their mass is approximately 10 tonnes for the coach, and six tonnes for passengers and luggage.
Comparing that with a two axle rigid truck, which I think has a laden maximum mass of 18tonnes (am I right here?)
In summary, there isn't much difference in laden mass, there is little difference in the maximum rate of braking.
I suppose that the driver of a coach cannot help but feel the responsibility for the lives of his/her passengers, and hence are among the safest drivers on the roads. However, I cannot imagine many truck drivers have a brazen disregard for safety either.
So, if the reason isn't technical, is it political, historical, anti truck prejudice?
number_cruncher
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Not so sure.
While there might be some unfairness at the level NC describes there's a fair difference between a coach with four wheels/10 tons and and an artic with eight and up to 44.
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A 44 tonne artic must have six axles, surely?
It has been some time since I knew the law on this, but artics with four axles - three of which will typically be double tyred - are limited to 32 tonnes.
I picked the case of the two axled rigid to be the closest possible vehicle to the coach.
number_cruncher
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In 1994 bus and coach speeds on motorways were limited to a maximum of 65mph and HGVs to 56mph.
Ironically, in 1988, it was ruled that all coaches first used from 1974 must have 70mph speed limiters fitted by April 1992.
The powers-that-be regard buses and coaches as very effective in both conveying a high number of passengers and reducing car use in major towns and cities. One coach is estimated to free/clear a mile of motorway of cars.
Unfortunately, for most people, the bus or coach is never going where they want to......:-)
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I would think that part of the reasoning is that the behaviour of a coach is more predictable should the driver have to deal with an emergency. The load balance is consistant no matter how many passengers a coach is carrying, whereas the load on a truck may be impossible to even out depending on what is being carried.
An artic is also inherantly less stable than a coach, being prone to jack-knifing under heavy braking.
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I take issue with Coach drivers being inherently safer. The last couple of instances when I used a coach I was scared half to death by the antics of the brylcreamed one in the front seat.
Possibly coaches are safer in design, having a longer wheelbase and lower CofG than a typical 18t truck?
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Statistically in terms of accidents per vehicle, coaches are much more safer than cars to travel in. Of course there are bad coach drivers, but there are far more bad car drivers.
To be honest I think many car drivers travelling in coaches do not make good passengers as they are used to being in control and hate the feeling of someone else being in control.
From 1994 onwards coaches weighing more than 7.5 tons GVW were banned from the outside lane of 3 lane motorways due to a change in EEC legislation requiring the setting of speed limiters to 65 mph. This has now been amended to the European standard of 100 kph (62 mph)
Trucks must have a speed limiter _set_ at 85 kph (53 mph)and the maximum powered speed cannot exceed 90 kph (56 mph). This is now being extended for all goods vehicles weighing more than 3.5 tons.
Buses and coaches weighing more than 3.5 tons or having more than 8 seats in addition to the driver will from next year require a speed limiter to be fitted _set_ at 100 kph (62 mph). A permitted tolerance of 5 kph or 5% of the set speed is permitted (whichever is the greater) giving an absolute maximum powered speed of 105 kph or 65 mph. Coaches are priority vehicles and that is why they have higher speed limits than goods vehicles on all but urban roads.
I drive for National Express. I do a return trip to London 5 days a week which is 180 miles. I have never had an accident in the coach *touches wood* ... i think that makes me a good driver.
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The two weak points on buses/coaches are:
1. Non-fiitting of or non-use of seat belts.
2. Inadequate roof strength in the event of a roll-over.
Most fatalities seem to happen in roll-over situations where the roof collapses - anti-roll bars would appear to be capable os saving lives.
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In 1994 bus and coach speeds on motorways were limited to a maximum of 65mph and HGVs to 56mph.
According to the Highway Code, they are at 70 and 60 respectively. Another case of the left hand of government not knowing what the right is doing?
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In the early days of the M1, Midland Red started an express motorway coach service. Midland Red used to design and build most of its own vehicles, even including the engines, up until the 1960's.
Its C5 coach pre-dated the Sinclair and Citroen namesakes by decades and regularly cruised up and down the M1 at 80 mph., A turbocharged version was tried and was said (in a book I've got)to be capable of exceeding 100 mph! However the turbos were removed before long.
Cheers, Sofa Spud
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I know a lot of car drivers will say they've been following HGVs or coaches exceeding their speed limits of 56/62 mph respectively. Apologies for those of you who already know but car speedos over-read typically by 5 - 10 percent and a GPS unit is the only way to measure speed accurately (i have 2 myself) and at a true 62 mph my speedo reads 68 mph in my car.
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Yay! One thing that I can hand-on-heart confirm is working on my Alfa is the speedo. At a registered 70mph dead on the dial my GPS reads a constant 69.5.
I can live with that kind of discrepancy.
I, er, can also confirm that at 120 it comes in at 119.2 on the GPS. Officer.
GPS system is not linked in any way to the car systems (palmtop based) so no leckytrickal magic going on.
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You must have a fairly new car or have new tyres to be that accurate on the speedo. The more prestigious makes of car usually have more accurate speedos judging from Autocar road tests.
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3.5 year old Alfa 156. The tyres were pretty new when I last checked the speedo a couple of months back.
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Two comments, presumably the tyres are still the original ones, and how do you get a tow truck to move that fast?
:-)
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Two responses, and the second one is "off!"
Third set of tyres (front) and I get them to move that fast by approaching their rear at a good 40mph speed advantage, flashing my lights and weaving from side to side.
See, I really wanted a 3-series.....
:op
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See, I really wanted a 3-series.....
Typical Alfa driver then?
;-)
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>> See, I really wanted a 3-series..... >> Typical Alfa driver then? ;-)
Actually, the typical Alfa driver wouldn't be seen dead in one, and the more orthodox have been seen to make gestures to ward off the evil eye when passing one.
ND is one of our forward thinkers.
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