Motorway Driving Question

RichardD1970

esuhl wrote: »

A lot of lorries are limited to 56mph, aren't they? Are the lorry drivers perpetually driving without due care and attention? Or is it that 6mph that makes the difference?

Thought it had recently been upped to 60.

esuhl

BeenThroughItAll wrote: »

Yes, they are limited, but that 56MPH limit takes into account the performance envelope and presented risk of an (up to) 44T articulated truck. Driving a truck at 70MPH would present a significantly increased risk over a car at 70MPH. Just as 50MPH in a car is really too slow, 70MPH in a truck would be, realistically, too fast - so the limit is set to accommodate that.


If a truck driver, chose to drive at a little over two thirds their mandated limit (ignoring the limiter, 60MPH) like the OP in this example, i.e. 40MPH on a motorway, would you consider that perfectly acceptable?

^^ That's not the comparison I'm making. It's irrelevant. The issue is not the amount of damage that vehicle could sustain, it's about the postulation that an object travelling at 50mph on a motorway is a hazard.

If a car travelling at 50mph is a hazard for approaching drivers, then a lorry at that speed will be just as much of a hazard.

AdrianC

RichardD1970 wrote: »

Thought it had recently been upped to 60.

You're thinking of the single carriageway NSL, which went from 40 to 50.
The motorway speed limit for an HGV is 60, but the vast majority of HGVs have to have calibrated speed limiters which restrict them to 90kph.

AdrianC

esuhl wrote: »

^^ That's not the comparison I'm making. It's irrelevant. The issue is not the amount of damage that vehicle could sustain, it's about the postulation that an object travelling at 50mph on a motorway is a hazard.

If a car travelling at 50mph is a hazard for approaching drivers, then a lorry at that speed will be just as much of a hazard.

You forget on thing - lobbing a car driver cruising along at 50mph, brain in neutral, into the middle of HGVs trying to maintain 56mph is going to cause a big ripple effect back along the motorway, because that car is acting as a rolling roadblock for absolutely no good reason whatsoever.

So, yes, the car driver WOULD be driving without due consideration for other road users.

If that car driver then decides that they need to be in a filter lane FAR, FAR earlier than they actually need to be, then that effect is magnified.

BeenThroughItAll

esuhl wrote: »

^^ That's not the comparison I'm making. It's irrelevant. The issue is not the amount of damage that vehicle could sustain, it's about the postulation that an object travelling at 50mph on a motorway is a hazard.

If a car travelling at 50mph is a hazard for approaching drivers, then a lorry at that speed will be just as much of a hazard.

I see you chose not to answer my question about when a driver's choice to drive slower than their limit becomes inappropriate?

AdrianC

BeenThroughItAll wrote: »

I see you chose not to answer my question about when a driver's choice to drive slower than their limit becomes inappropriate?

When they're driving without consideration for other road users.

And, before you ask "In whose opinion?", the answer is in the opinion of the policeman who would stop them, then - if they don't take the hint and refuse the fixed penalty - the magistrate who would be presiding over their case.

esuhl

AdrianC wrote: »

You forget on thing - lobbing a car driver cruising along at 50mph, brain in neutral, into the middle of HGVs trying to maintain 56mph is going to cause a big ripple effect back along the motorway, because that car is acting as a rolling roadblock for absolutely no good reason whatsoever.

A "rolling roadblock" reducing the traffic speeds of ONE lane by SIX mph is hardly a big issue. That jogging speed! :rotfl: Most motorways have three lanes, and lorries can use the middle lane to overtake, causing no one any delays at all unless it's very congested.

And if there is that much traffic, slowing it to 50mph tends to increase average speed as there is less bunching as vehicles have more time to react. Throughput also increases as the safe distance apart from vehicles decreases the slower they go.

AdrianC wrote: »

If that car driver then decides that they need to be in a filter lane FAR, FAR earlier than they actually need to be, then that effect is magnified.

Perhaps, but again it's hardly a big deal, is it? It's effectively a pinch-point. If you slow from 70 to 50mph for a whole mile, it will take 1m12s instead of 51s. OMG! You've been delayed by 21 seconds!!!

AdrianC

esuhl wrote: »

A "rolling roadblock" reducing the traffic speeds of ONE lane by SIX mph is hardly a big issue.

Except it isn't that simple, is it?

You've now got all the wagons which would otherwise be happily in L1 suddently trying to get into L2 to get around the numpty bimbling along in L1 oblivious - always assuming, of course, that they ARE in L1, which is probably a step too far. If/when the wagons have to slow down, they don't accelerate quickly again, so the overtake is much slower and longer.

Then you've got all the traffic that was in L2 trying to get into L3.

If you really think it isn't a problem, then you've not tried driving at an indicated 50 (actually a real high 40s) on a motorway - or, if you have, you have zero awareness. I've driven genuinely slow stuff far enough to know that I find it frankly terrifying to sit just below HGV cruise speed. There is no way on the face of this planet that I'd sit at that sort of speed voluntarily, in something perfectly capable of making more appropriate progress.

esuhl

BeenThroughItAll wrote: »

I see you chose not to answer my question about when a driver's choice to drive slower than their limit becomes inappropriate?

FWIW, I'd say, on a typical motorway with a clear lane in front, 50 to 55mph would be the lowest appropriate speed. Any slower than the OP was travelling at would be excessively slow.

The maximum speed of vehicles on motorways ranges from 56mph to 70mph. So setting a minimum speed at a jogging pace slower than some vehicles maximum speeds doesn't sound like anything a reasonable person could complain about.

BeenThroughItAll

AdrianC wrote: »

When they're driving without consideration for other road users.

And, before you ask "In whose opinion?", the answer is in the opinion of the policeman who would stop them, then - if they don't take the hint and refuse the fixed penalty - the magistrate who would be presiding over their case.

You know I wasn't actually directing that at you, right? And that I am in no way disagreeing with the point of view that the OP was driving too slowly, and without due consideration and care for other road users. Quite the contrary, I was challenging the point of view that just because trucks etc are limited to 56MPH then 50MPH is also perfectly OK.