Are speed cameras too conspicuous?

[bramling]

What I tend to find is a source of a little frustration is that people driving manually tend to keep the accelerator pretty static so will lose speed on uphills and gain it on downhills, whereas cruise maintains the chosen speed exactly.

Losing speed uphill and picking up downhill does greatly enhance fuel economy, so I’m not sure it’s a bad thing. I will normally allow a slight drop upon reaching a summit, and make up for it by allowing things to pick up going down. One certainly wants to have some momentum gained at the bottom of a climb.

I don’t fine cruise particularly useful on motorways, except occasionally on long journeys at night, or for specific applications like roadworks. Having a ceiling set at which the engine cuts out is more useful, but something to watch as it can mean the engine cuts out when you don’t want it to (which can even be potentially dangerous).

 

[Bletchleyite]

Except in London, where it encouraged many to buy big wide fuel hungry SUVs so they could drive over them easily, or straddle the cushions.

I think one of London local reporters discovered that roads with these have 30-35% higher emissions than a road with similar traffic volume with no calming. Lower gears and braking and acceleration causes it. The high emissions side effect is usually omitted from most discussions about them as it is so embarrassing to most councils to admit to raising pollution.

Slowing traffic down so you need a lower gear increases pollution anyway, that's a given based on how ICEs work with limited power bands. It's effectively acceptable collateral damage against the safety benefits.

Electrics, OTOH, will use less power the slower they go.

Losing speed uphill and picking up downhill does greatly enhance fuel economy, so I’m not sure it’s a bad thing. I will normally allow a slight drop upon reaching a summit, and make up for it by allowing things to pick up going down. One certainly wants to have some momentum gained at the bottom of a climb.

It's not an issue if driving manually, it just serves to frustrate when using cruise control as you end up jostling for position with the same car.

Adaptive is probably better as that varies your speed to keep an appropriate distance from the car in front.

 

[bramling]

It's not an issue if driving manually, it just serves to frustrate when using cruise control as you end up jostling for position with the same car.

A good reason not to use cruise on motorways, it just doesn’t really work well for various reasons - this being one.

 

[AM9]

A good reason not to use cruise on motorways, it just doesn’t really work well for various reasons - this being one.

With the M25 and southern M1, except in quiet times, the speed of traffic can vary so much that cruise can be a bit of a problem.

 

[bramling]

With the M25 and southern M1, except in quiet times, the speed of traffic can vary so much that cruise can be a bit of a problem.

I don’t think it encourages good driving habits at all. For a start it encourages people to get closer than they should, but at higher speed ranges I think it causes people to lose their mental connection with the road.

Just taking the London end of A1(M) there’s various features that one really doesn’t want to negotiate on cruise for various reasons, and in particular it encourages very nasty cornering (IMO) on some of the sweeping but fairly sharp by motorway standard curves. This is even when the road is fairly quiet.

I will tend to use cruise for lower speeds like your example of 30 and 40 areas, plus it’s a lifeline in 50 mph motorway roadworks. But for normal motorway driving forget it, apart from the occasional overnight run - and even then that introduces a different issue, risk of boredom and tiredness.

 

[JohnMcL7]

Although it's not required the static cameras are mostly made to be highly visible to act as a deterrent, nothing to do with technological limitations.

However you pretty much have your wish already since a large percentage of speed enforcement is now handled by camera vans that can catch speeders at up to 1 kilometre away long before the drivers have a chance to see the vehicle.

 

[Bletchleyite]

A good reason not to use cruise on motorways, it just doesn’t really work well for various reasons - this being one.

I find it's the only place I would ever want to use it. Other roads have too many features that make you want to adjust your speed frequently.

 

[radamfi]

If you have a new car with ISA, a lot of the time you would be speeding blatantly as you have to override or fail to switch on the system. Other people who are blatantly speeding are people who overtake cars travelling at 30 mph. These people are not risk averse enough to be driving.

 

[bramling]

I find it's the only place I would ever want to use it. Other roads have too many features that make you want to adjust your speed frequently.

Each to their own, however I find it harmful to fuel efficiency, and at times bordering on hazardous. I don’t think I’ve ever used it on any of the motorways as they approach the London area.

 

[JamesRowden]

With modern technology, speed cameras could be drones that hide behind different bridges and signs during the day. A random function could be used to make their selection unpredictable.

 

[cactustwirly]

It is very easy to keep *below* the maximum speed limit too

If the conditions are good then you should be driving at the speed limit.
Driving too slowly can be dangerous

 

[PeterC]

I find that setting cruise control to either just below 70 or just over it (bearing in mind that an actual 70 by GPS in my car is an indicated 73) means you get a reasonable differential from others and don't start overtaking like a lorry.

As the cruise setting on my car isn't adaptive I find it easier to set the speed limiter instead. I find that petrol consumption is better that way too.

 

[cactustwirly]

I find that selecting the gear which is the first number of the lower limit you want to adhere to works fairly well on most cars.

That is 2nd for 20, 3rd for 30, 4th for 40, 5th for 50 and 6th for cruising at 60 or above.

Depends on the gear ratios.
If I cruised at 30 in 3rd I'd burn through a lot of fuel.
1st is for setting off only, 2nd is from 5 to 20mph, 3rd from 20 to 30mph, 4th is 30 to 40mph on my car and 5th is 40+

 

[PeterC]

It is very easy to keep *below* the maximum speed limit too

Were you the guy I passed on an empty motorway who was doing 50 in the middle lane one night last year?

 

[cactustwirly]

Unfortunately most motorists are somewhat intolerant of this, as anyone who regularly cycles on the roads will have discovered.
There are plenty of "30-zones" where 30 is achievable in a car, but not by the average cyclist. Tailgating is unfortunately common on these roads.

What do you expect motorists to do?
The so called "tailgating" makes it easier for the driver to overtake the cyclist.

 

[py_megapixel]

What do you expect motorists to do?
The so called "tailgating" makes it easier for the driver to overtake the cyclist.

I expect them to stay a couple of metres behind until there is actually space to overtake.
It's incredibly intimidating to have a huge Range Rover so close that it would knock you off if you had to brake.

 

[AM9]

What do you expect motorists to do?
The so called "tailgating" makes it easier for the driver to overtake the cyclist.

Were you not taught about stopping distances before you passed your test?

 

[DJ_K666]

I expect them to stay a couple of metres behind until there is actually space to overtake.
It's incredibly intimidating to have a huge Range Rover so close that it would knock you off if you had to brake.

Try it with a bus lol. I do try to acknowledge the cyclist if I'm behind them waiting for it to be safe. That way they know I've seen them. It can be frustrating though as you can't always see if there's any oncoming traffic around the next bend and you just know what's going to happen if you just floor it.

 

[LSWR Cavalier]

Best to leave a much bigger gap than 2m

 

[Ianno87]

Try it with a bus lol. I do try to acknowledge the cyclist if I'm behind them waiting for it to be safe. That way they know I've seen them. It can be frustrating though as you can't always see if there's any oncoming traffic around the next bend and you just know what's going to happen if you just floor it.

If you can't see, you don't overtake. That's pretty basic stuff, to be honest.

 

[cactustwirly]

Were you not taught about stopping distances before you passed your test?

Yes I was, but you don't need to leave acres of space, especially at 20mph. You leave a sensible distance

 

[bramling]

Yes I was, but you don't need to leave acres of space, especially at 20mph. You leave a sensible distance

Depends how one defines sensible. What happens, for example, is the cyclist hits a pothole and comes off? A couple of metres won’t be enough to stop.

People have a habit of failing to correctly judge stopping distances as well as anticipating potential hazards. Round here there’s a rural B-road which has particular issues with deer incursion, particularly in the evenings. It really maddens me when people tailgate, as if I need to brake sharpish to stop short of a deer, chances are they will fail to react quickly enough.

 

[AM9]

Yes I was, but you don't need to leave acres of space, especially at 20mph. You leave a sensible distance

The stopping distance from 20mph is 40ft. A cyclist falling off a bike can stop within 10-15ft.

 

[cactustwirly]

The stopping distance from 20mph is 40ft. A cyclist falling off a bike can stop within 10-15ft.

And in metric?

 

[py_megapixel]

And in metric?

You can google that as well as anyone else can... 40ft is approx 12m; 10-15ft is approx 4-5m

Of course 4 metre gaps between every vehicle on the road probably isn't sustainable, but if AM9's figures are to be believed - and they sound very plausible - it definitely indicates that drivers who drive right on the tail of cyclists are risking seriously injuring said cyclists if they had to stop in an emergency.

 

[cactustwirly]

You can google that as well as anyone else can... 40ft is approx 12m; 10-15ft is approx 4-5m

Of course 4 metre gaps between every vehicle on the road probably isn't sustainable, but if AM9's figures are to be believed - and they sound very plausible - it definitely indicates that drivers who drive right on the tail of cyclists are risking seriously injuring said cyclists if they had to stop in an emergency.

4-5 metres is a sensible distance, and is how much I normally leave.
12 metres sounds like an excessive distance for less than 20mph, obviously when I'm behind a car at faster speeds I leave much more than that.

 

[AM9]

4-5 metres is a sensible distance, and is how much I normally leave.
12 metres sounds like an excessive distance for less than 20mph, obviously when I'm behind a car at faster speeds I leave much more than that.

12m includes thinking distance which everyone uses. 4-5m is barely more than a single car length, - if that is a 'sensible' distance, it's not surprising that so many cyclists are injured.

 

[Bald Rick]

I think in the early days not every speed camera actually had a camera installed, so they were there as a visual deterrent

And many still don’t.


On French autoroutes there are signs up on the approach to speed cameras advising that a ‘controlée radar’ is just ahead.

The best example I ever saw was on the M4 eastbound in the outer suburbs of Western Sydney. There must have been 5 signs counting down the Kms until the camera, and then one practically next to it saying SPEED CAMERA HERE.

 

[cactustwirly]

12m includes thinking distance which everyone uses. 4-5m is barely more than a single car length, - if that is a 'sensible' distance, it's not surprising that so many cyclists are injured.

I don't understand that, 20 mph isn't very fast so the braking distance definitely isn't 12m. It's what I've been taught, as it makes overtaking cyclists much safer.

Where does it say in the highway code you must leave 12m for cyclists??

 

[JamesT]

I don't understand that, 20 mph isn't very fast so the braking distance definitely isn't 12m. It's what I've been taught, as it makes overtaking cyclists much safer.

Where does it say in the highway code you must leave 12m for cyclists??

Rule 126 on stopping distances says:

leave enough space between you and the vehicle in front so that you can pull up safely if it suddenly slows down or stops. The safe rule is never to get closer than the overall stopping distance

That applies for all vehicles, not just cyclists. The braking distance listed in the Highway Code is 12m for 20mph (6m thinking + 6m braking).