Road Speed Limits

[FB.]

Am I the only one who bothers to drive anywhere even close to speed limits anymore?
The only one who allows a safe stopping distance?


On almost any road, I'll accelerate briskly and get up to speed (often opening quite a gap between me and the car behind), then once up to speed I'll be sitting at the speed limit (give or take a couple of mph) yet everyone in front quickly disappears into the distance while an impatient, bunched-up "tailgating" queue forms behind me.

No wonder there are so many multi-car accidents and accidents in wet weather.
A running joke in this area is that anytime there's a single spot of rain land anywhere on the major roads near Cambridge we'll get a massive, fatal pile-up on one of those nearby major roads (A10/A14/M11).

[AllInContainers]

Plenty of horrendous drivers round here too. Stopping distance is even more critical than speed in my opinion. If it's a road with no pedestrians to suddenly cross in front of you, conditions are good, and there's no other traffic on the roads, I can understand drivers getting a bit of a heavy right foot temporarily

I hate tailgaters though, and there is no excuse for not giving yourself room to stop if the car in front has a problem. The only time I will be "conservative" with space in front of me, is if I know there's an idiot in the next lane who is out hunting for the opportunity to hurtle into any roughly car sized gap and then slam the anchors on You can spot them a mile off with their twitchy driving. I feel safer having a slightly more limited stopping distance, and them out of the way, than with them pulling stupid tricks in my path. Let them find another bit of road to be dangerous on, rather than the bit immediately in front of me

[RedThorn]

I drive a lot. What people fail to realise, is the speed limit is a limit for ideal driving conditions and not a target to aim for

[snuffer]

One of the strange driving practices that gets me is 'The 40 mile an hourer'. He will sit there at 40mph holding up a great stream of traffic. Then when he comes to a 30mph zone he'll doggedly stick to 40 and sail away off into the distance while everyone else slows to the speed limit. VERY STRANGE.

Then of course there's the 'but I'm a law abiding citizen why don't the police bother real criminals'. Sorry if you deliberately break the speed limit then you deliberately break the law and are no longer a law abiding citizen.

Whenever there is a speed trap in the village the operators pull in a substantial number of drivers. These are a team of about 3 or 4 police officers, all dressed in bright yellow high viz. jackets and still some of the numpties don't see them. They deserve their fine and points.

[FB.]

Stopping distance is even more critical than speed in my opinion.

Agreed. Although I don't drive at 90mph and might spend my whole life having never taken my car above about 75mph; on some roads there are definitely times when the road ahead is sufficiently clear, road conditions sufficiently good and long-distance visibility sufficiently good that it would be safe to do so.

However, it has often been shown in surveys that eight out of ten drivers think they're better than average.
But only four or five out of ten can be better than average, which leaves three or four out of ten drivers (30-40%) who are over-estimating their skill level and who may eventually end up decapitated under the back of a lorry trailer because they thought they were better than average and able to tailgate at distances where even the thinking distance isn't covered, let alone the braking distance.

Actually, I once derived a formula for thinking and stopping distance, so that I don't need to remember individual apparently random numbers.
Here it is:

The typical total stopping distance, in feet, is equal to:
2x your speed in mph at 20mph.
2.5x your speed in mph at 30mph.
3x your speed in mph at 40mph.
3.5x your speed in mph at 50mph.
4x your speed in mph at 60mph.
4.5x your speed in mph at 70mph.
5x your speed in mph at 80mph.

There are 3.28 (three and a quarter) feet per metre.

So comparing those rough reckoners with actual numbers from the highway code:
Speed........highway code says.........my formula says
20mph..............40ft.......................... 2 x 20 = 40ft (three car lengths)
30mph..............75ft.......................... 2.5 x 30 = 75ft (five car lengths)
40mph..............118ft........................ 3 x 40 = 120ft (eight car lengths)
50mph..............175ft........................ 3.5 x 50 = 175ft (twelve car lengths)
60mph..............240ft........................ 4 x 60 = 240ft (sixteen car lengths)
70mph..............315ft........................ 4.5 x 70 = 315ft (twenty-one car lengths)
80mph..............illegal!...................... 5 x 80 = 400ft (twenty-seven car lengths)
90mph..............illegal!....................... 5.5 x 90 = 495ft (thirty-three car lengths)

An average car is about 15ft long, with the smallest cars being about 12ft and the largest about 18ft.

In each case (assuming you're caught by surprise and your brain has to process the information before instructing your feet to react) the thinking distance in feet is roughly equal to the speed in mph. The rest is braking distance. So at 60mph it's 60ft thinking distance (four car lengths) and 180ft braking distance (twelve car lengths).

[chris]

I drive just over 80 miles each day to and from work.. I've witnessed some shocking driving, accidents and cyclists over the past couple of years in doing this commute.

Even on the other side, I had to swerve off onto the hard shoulder in HEAVY rain, when doing 60 in the inside lane (others in the other lane doing far in excess of the limit), only to come across some moron doing 30... ON THE MOTORWAY !

I swerved off, as I had no chance of stopping (no lights on, rain and my speed all combined - with seeing the driver only at the last moment) - and if I hadn't of, the car behind me would have definitely hit me, as they stopped and shunted the car.. so my car's distance would have seen them travelling probably around 20mph or so into the back of me. Unbelievable.

This morning I went to over take someone in the middle lane, accelerating up to 75 odd, only for them to speed up faster than I'm going - so I pulled back in, then back over to the inside lane, for them to drop back again. This happened twice, before I decided to undertake the t**t (at 70). May or may not have hoped for him to have a crash.

[FB.]

.....(no lights on, rain and my speed all combined - with seeing the driver only at the last moment) .....

Part of my collection of road-related topics stems from the new car (due to baby coming) and the test-driving to select a car followed by using the new car as much as possible so we can get used to its quirks.

Anyway....to the point.... quite a lot of new cars these days have LED "running lights" which are always on whenever the engine is running - day or night. They seem like a very good idea.
My new Astra has them, and it changes the brightness of the running lights depending on the light conditions and/or depending on whether I've got the headlights on. For example: last week I pulled up to my garage door around 11:30pm, and noticed that as I switched the headlamp dial from normal beam through parking lights through to off, the LEDs came on more brightly to compensate (of course, the car didn't know that I was parked on my drive; I could have been anywhere).

Lots of people seem to think that lights are to light the way for them, when, in fact, lights are mostly to make it easier for other drivers to see your car coming in the gloom of dull days, dawn or dusk!
Full beam lights are to help in seeing where a car is going!

When we recently bought some new Christmas lights, we were amazed at how low the power consumption of LEDs. Our old lights used about 100Watts of power but the similar LED lights use about 5Watts. It's amazing how efficient LEDs are.

I could run five hundred strings of one-hundred LED fairy lights for the same power consumption as running my kettle or my hot water immersion!

[PyreneesPlot]

Tailgating is a national sport here in France and often it doesn't seem to be an attempt to push you along or even waiting for a chance to overtake.

Speed limits? Nope never heard of them

It's the only thing I hate about living here. Try doing 30kph in a 30 zone outside a school and you will be overtaken. And being tailgated when riding a motorbike can be terrifying.

[FB.]

Tailgating is a national sport here in France and often it doesn't seem to be an attempt to push you along or even waiting for a chance to overtake.

Speed limits? Nope never heard of them

It's the only thing I hate about living here. Try doing 30kph in a 30 zone outside a school and you will be overtaken. And being tailgated when riding a motorbike can be terrifying.

I have long been under the impression that laws in France are treated more like optional guidelines.

I think the current UK driving testing criteria are supposed to be among the most demanding in the world. So judging by the number of muppets on the UK roads I'm not surprised that a lot of other nations have terrifying road behaviour!

We went to Jersey (hired a little Ford Ka for a week) about ten years ago and people were very good on the roads there - courteous, well-behaved and even gently tooting the horn as a warning to other cars at the numerous "blind" country-lane crossroads; just what a horn was actually intended for!

[crannman]

im a hgv driver on A roads 40mph is our speed limit try sticking to that when you have a queue of traffic behind and yes i DO keep to the limit but the abuse you get from other drivers is not to nice same on duel carrageways 50mph motorways 56mph

[Mikey]

Its only as I've got older have I become more aware of my driving, I rarely get close to the speed limit which infuriates the other half. Optimal fuel efficiency is around 56-60 mph, this is the speed I drive. I don't accelerate hard, I never exceed 3000rpm, and generally change gear before 2000rpm. This gives me between 7-9 mpg extra from my tank and considerably more when on the motorway. I see traffic slowing well in advance and aim to allow the engine to reduce my speed rather than the brake.

I'm sure there will be those out there that find my driving style maddening, but I really don't care, I like to leave in plenty of time to get where I need to go, heaven help the other road users when I get a caravan then I'll truly know what an open road is....

[FB.]

I don't accelerate hard, I never exceed 3000rpm, and generally change gear before 2000rpm.

Peculiarly, I don't accelerate particularly hard (my passengers don't have their drink spilled on them) - I just go up the gears quite quickly. As a result of quickly going up the gears I seem to leave other drivers behind me until my speed reaches a plateau at 30mph and they catch me up at 35-40mph.

I tend to also have the rpm in the 3000 range.

Actually, the car I (we) have now has a "gearchange-nag" light which comes on, telling the driver to shift up the gears. I don't often get nagged (my wife does!) but sometimes the nag is a bit keen because it doesn't realise that it's not worth me shifting up to 4th due to me expecting to have to slow or stop at the next set of traffic lights or roundabout (of which there are far too many holding up the traffic in and around Cambridge).

Our Astra - with only a modest 1.6L, 4-cylinder, petrol engine - seems to be good getting up to 30-35mph quite quickly (up to 4th gear, 30mph, 2k-3k rpm) but the 4th and 5th gears (no sixth gear) have to cover quite a broad range of speeds above 30-35mph; not an issue for me, but would be an issue for anyone wanting to continue accelerating hard above 40mph or so.

[FB.]

im a hgv driver on A roads 40mph is our speed limit try sticking to that when you have a queue of traffic behind and yes i DO keep to the limit but the abuse you get from other drivers is not to nice same on duel carrageways 50mph motorways 56mph

My father was a lorry driver (he retired about 20 years ago - he died several years ago). Even with the worsening traffic on Cambridge's roads twenty years ago he was glad to give it up - and he was one of the company's best drivers who would often be asked to make a drop or collection in a particularly difficult-to-manoeuvre place.

With the roads as bad as they are in this area, I sympathise with lorry drivers and do my best to be patient and give them plenty of room. Unless you're driving particularly dangerously (we all make the odd mistake) I can assure you that it won't be me cursing at you.

[dogsbody]

Even before I did our company's defensive driving course (the NHS does some strange things!) I was aware of the 2 second rule (only a fool breaks the two second rule) and was most interested to hear the instructor suggest double that in wet conditions PLUS he suggested you should always drive "on the brakes of the guy behind" i.e. the closer they get the bigger the gap to the vehicle in front is what you should leave. Gives a whole new meaning to the old bumper sticker "the closer you get the slower I go".

The whole point is to avoid being in someone else's accident.

[FB.]

always drive "on the brakes of the guy behind" i.e. the closer they get the bigger the gap to the vehicle in front is what you should leave. Gives a whole new meaning to the old bumper sticker "the closer you get the slower I go".

The whole point is to avoid being in someone else's accident.

Yes, for every foot too close the driver behind happens to be, you should be allowing that extra foot in front of you so you can brake slowly enough for him to have time to react.