Cotswold. A valid question which I will endeavour to answer.
Prior to the rigid enforcement of speed limits by mobile and fixed cameras sites, only ‘token’ notice was taken of the 40mph on single carriageway roads. The drivers don’t like it. Motorists don’t like it. The trade associations have spoken out against it. Even a Peer, a former driver, has addressed the House of Lords on the matter. But the Government seems unwilling to budge on the matter. After all “Speed Kills” is what we are all led to believe.
With regard to pulling into lay-by’s to allow traffic to pass, as has already been mentioned, getting out again can be a problem and could even make roads more dangerous. What you need to remember is that from stationary, even a moderately laden large vehicle will take somewhere in the region of 15-20 seconds, to reach just 20mph, and will probably require three or four gear changes. And then there is the fuel penalty. With such vehicles averaging in the region of 8 – 12 miles per gallon, and fuel amounting to approximately 30% of a vehicle’s running costs, there is an interest in maximising fuel usage.
A few years ago the Treasury set aside £100 million for the Transport Energy/Best Practice programme, which encompassed the SAFED (Safe and Fuel Efficient Driving) scheme. £56 million was later clawed back by the Treasury and the funding ended just when, in my opinion, the benefits were becoming visible. The principle mantra of the SAFED scheme was, ‘to keep the wheels moving’, principally by advanced observation and anticipation.
To quote from some of the training material from the scheme, 0-40mph typically burns 0.54 litres of fuel. Slowing to 15mph and then returning to 40mph typically consumes 0.42 litres of fuel. A 23% saving in fuel usage, along with savings in harmful gasses and particulates. With bonuses often linked to fuel savings, there is a valid disincentive against pulling in to allow vehicles to pass.
For many years E.U. Legislation has demanded that speed limiters for these type of vehicle are set to 56mph (Or more correctly, 85kph + or – 5%) and as such, manufacturers produce vehicles with a final drive ratio that ensures that the rev counter sits at the most economical point when travelling at that speed. However, at 40mph, in top gear, the needle invariably rests just below the ‘economy’ band and renders the vehicle sluggish and unresponsive. At 45mph, the vehicle is more ‘comfortable’ both in driving terms in relation to responding to gradients, and cab vibrations.
cotswold wrote:
To me this is a borderline one - for a tractor, JCB, etc the answer would definately be "yes" - but what about effectively restricting other drivers to 40mph when they would be legally entitled to drive at 60mph if safe so to do.
Remember that it is not the user that is restricting the progress of other motorists. It is the Legislators. On most Primary routes they could easily be driven at speeds of 45mph and 55mph with no detriment to safety.
The counter argument of course is that over the years the maximum weight has risen from 32 tonnes to 44 tonnes, and therefore, by definition, these vehicles pose a greater threat.
What is conveniently overlooked in this argument is the engineering advances that have taken place over the years. In the old days, if you ran out of air, you ran out of brakes. Nowadays, if you run out of air, the vehicle stops. All are fitted with ABS or EBS. Not to mention ESP (Electronic Stability Program) or RSP (Roll Stability Program), or that manufacturers are developing accelerometers to warn of lateral instability. There is even a ‘Lane Follow’ system that detects when a vehicle starts to drift out of it’s lane and plays a ‘rumble’ warning through the appropriate radio speaker.
Rewolf wrote:
I'm sure that they don't want to the be cause of the obstruction, but the stupid limit is the stupid limit and they lose their job if they get caught breaking it, but the job schedule is already hard to achieve due to congestion, and they also lose their job if they were always late beause they kept stopping (it's on the Tacho).
It’s not just about stopping. Many of the larger companies now use ‘tracking’ devices whereby they can constantly monitor a vehicle position, direction, and speed, with written warnings and dismissal for those not adhering to Company policy. Additionally, it is not unknown for VOSA, when visiting an undertaking based some distance from the nearest Dual Carriageway or Motorway, to examine the speed traces and take action against drivers exceeding the limits on nearby roads.
I can appreciate the frustrations, mainly because 40mph is so damned boring. When you’ve finished your sandwiches, drunk your tea, had a good scratch around the sweaty bits,

your still sitting there looking for something to occupy the mind. You almost want to get a book out to read.

And believe me, some do.
cotswold wrote:
My reason for asking the question is we're looking at forthcoming education campaigns based around motorway services - I'm just wondering whether the "pull over" message is worth including.
It would not receive the support of the RHA or the FTA and, for the reasons explained, runs contrary to Government funded training.