Reply to: Overtaking on a slip road

[OwlHoot]

Like a lot myths, this is based on a grain of truth, the original British Standard for car speedometers was +/- 10% of actual speed, so if you’d calibrated your speedo against a measured mile, you could get away with exceeding the speed limit.

Car speedometers are now subject to EU Standards, these state that:

Lower limit - They should never show less than the actual speed
Upper limit - They should never show more than 110% of actual speed + 6.25mph

What this means is, if your speedo is showing 70mph, you will not be doing more than 70mph, but you may only be actually travelling at 58mph

Underinflated tyres can also make the speedo show a higher speed than it should, although obviously it's dangerous to drive fast with flat tyres.

[Magpie252]

The inaccurate speedo thing (aka you can do 10% over the limit and they won't touch you) is a myth, I'm afraid. It's illegal for a car speedo to under-report the actual speed.

Like a lot myths, this is based on a grain of truth, the original British Standard for car speedometers was +/- 10% of actual speed, so if you’d calibrated your speedo against a measured mile, you could get away with exceeding the speed limit.

Car speedometers are now subject to EU Standards, these state that:

Lower limit - They should never show less than the actual speed
Upper limit - They should never show more than 110% of actual speed + 6.25mph

What this means is, if your speedo is showing 70mph, you will not be doing more than 70mph, but you may only be actually travelling at 58mph

[NotAllThere]

<bzzzzz> deviation

What?

Er....

damn.

[SpontaneousOrder]

There are give way markings at the end of the slip road, so it shouldn't really be that hard. If there's no space, then stop and wait until there is

[Peoplesoft bloke]

Police Interceptors tonight - PistonHeads

[BrilloPad]

The police are not there to uphold the law.

They are the law.

HTH

[vwdan]

Yes but if you're in lane 2 of the slip road you have to prepare to join straight into lane 2 of the motorway. "Roadcraft", the advanced driving manual, has a diagram explaining this.

You should stick to the left-hand lane pal.

I'll have to take your word for as I don't have the car version to hand, but I can see nothing of the sort in my Motorcycle Roadcraft manual and it's not something that I've ever heard mentioned on any advanced course I've done. Also, Roadcraft isn't the "Advanced Driving Manual", it's the Police Drivers manual. Both ROSPA and IAM do their own thing, separate to the book AFAIK.

I'm happy to be wrong, but I can't figure out a safe and appropriate way to find yourself parallel to another car at the end of a merge lane. That would highlight bad planning and anticipation to me, but I guess it's easier to plan an overtake on a bike, so maybe it just never came up. That and motorways are the dullest road on a bike, so trainers tend not to head that way.

Edit: Oh jeez, just realised who I'm responding to. Never mind.

[Cenobite]

Eh? Since when - most sliproads merge at the end and, if they don't, they're streamed into separate merge points for lane one.

Yes but if you're in lane 2 of the slip road you have to prepare to join straight into lane 2 of the motorway. "Roadcraft", the advanced driving manual, has a diagram explaining this.

You should stick to the left-hand lane pal.

[stek]

I'd assumed that you were alluding to the fact that car (and bike) speedos are deliberately calibrated to OVER read speed - hence an indicated 75 is almost certainly going to be no more than a real 70.

The official police guidelines a few years back are 10% + 2. I.e. 35 in a 30.

The 2 is 'at the Chief Constables discretion' and the they have been told not to exercise it now. That's what I was told at my speed awareness course. Which I was late for, had to drive like the clappers to get there...

[vwdan]

If you are joining the motorway on lane two of a slip road then you've got to be prepared to join the motorway's lane two directly. That takes a lot of observation and planning to do.

Eh? Since when - most sliproads merge at the end and, if they don't, they're streamed into separate merge points for lane one.

[Cenobite]

If you are joining the motorway on lane two of a slip road then you've got to be prepared to join the motorway's lane two directly. That takes a lot of observation and planning to do.

[pjclarke]

The clue is in the term "dual carriageway".

With the carriageway being the operative bit. That is, any highway where the two traffic flows are separated by a physical barrier is a dual carriageway, so a road with just one lane in each direction with a raised kerb or a crash barrier is a dual carriageway, but two or even three lanes each way just separated by painted white lines is not.

I never knew that.

[SpontaneousOrder]

Are you in London or a smaller area?

The police in places I drive aren't interested if you do a couple of mph above the speed limit i.e. 33mph in a 30 zone. Where they are bothered by that there is a speed camera and the council will have put in loads of road humps. If you stupidly do 40 mph to the speed camera then brake then if the police are about they will pull you over. That ignores the fact you risk hitting a jaywalking pedestrian or a cyclist who randomly pulls out.

On the motorway and dual carriageways I have been warned where the police tend to concentrate. However I've personally noticed they aren't interested in you going at 80mph on the motorways I tend to drive on.

I'd assumed that you were alluding to the fact that car (and bike) speedos are deliberately calibrated to OVER read speed - hence an indicated 75 is almost certainly going to be no more than a real 70.

The official police guidelines a few years back are 10% + 2. I.e. 35 in a 30.

[VectraMan]

( And I never knew that the definition of a dual carriageway, and hence a 70 limit, has nothing to do with the number of lanes. )

The clue is in the term "dual carriageway".

People who stop at the end of sliproads are the worst. Because then you've turned what's already a bit of a dangerous situation into an extremely dangerous situation, both to the people on the carriageway and anyone else coming down the slip road.

[pjclarke]

Are you in London or a smaller area?

Well, I live in the Peak District in a tiny remote village (where 30 is legal but unsafe in my view) but I was 'busted' driving thru Macclesfield (largish town) on a quiet Friday night on my way home from MAN airport.

I never consciously break the limit, and will be even more vigilant after seeing those fatality stats. On this occasion I missed the demotion of the road down from 40 to 30, the sign was obscured, and there was no apparent reason for it, wide road, houses set well back, good visibility. But there ya go, not whining, it was my fault.

Yeah, most police seem fairly sensible about minor/borderline infractions, just sayin' that thing about a 10% tolerance on your speedo has no basis in law....

( And I never knew that the definition of a dual carriageway, and hence a 70 limit, has nothing to do with the number of lanes. )