Flashing headlights

[Jon M]

Hi all, I watched the Roadcraft video for the first time a little while ago, and was left wondering about one of the points made on it. Driving along the motorway, the driver is overtaking some traffic in lane 1 and notices a car which he is about to pass closing on the vehicle in front of it. He gives that vehicle a long headlight flash, 'to make the other driver aware of our presence'. Personally I can only think of one message that would send to the other vehicle, which is that you are inviting him to move out in front of you! Presumably you would give the flash when you get close enough for it to be obvious you're not letting him out? It still doesn't seem like a great idea to me, I wonder if anyone could explain whether it's still considered good practice and how you can do it without being misinterpreted?

Thanks
Jon

[Rick]

It is still taught in some advance driving circles. The thing with it is as you said " a long flash" this is used in the way that headlight flashes are supposed to be used and as per Highway code. I dont use this method myself because of the danger of confusion. It is ok if people are on the ball but as there are many people driving about without a clue i would prefer to slow down a little to make sure the vehicle was not going to come into my lane.

[Roadcraft]

In the police car...I 'long flash'...only on motorways with blue lights on..

In my own car...the only 'flash' I do..is on single lane roads, prior to overtake...

If there is any chance another driver might take my flash as a 'invitation' to move out...I WON'T DO IT...

[vonhosen]

I do use this method a lot at work. Particularly where making progress when not using blues & twos. If it used well there is nothing ambiguous about it at all.

The use of the headlamp flash is a very useful tool particularly on motorway & dual carriageway, but it is something that if not done or timed well can appear aggressive. It is unlikely that you would have to use it much if driving within our speed limits. It would be used where your speed is greatly different to others on the road, others who's potential movement concerns you with the speed you are carrying or wish to carry.

A few points of note.

If you are going to give the headlamp flash in such situations it needs to be at least 4 seconds.

It must be given in good time.

It doesn't mean "I'm coming through" it means "Look at me I'm approaching quickly, what are you going to do ?"

You have to give it in good time, time for others to respond to it either positively or not, & leaving good time for you be able to respond to their response smoothly, matching speed with them if they do pull out smoothly not abruptly.

Prior to you committing to passing the vehicle you should have released the headlamp flash. Now with it being at least 4 seconds in length as I said earlier, that means you have to be doing it some distance back. There is an optimum distance but this will differ depending on your speed, the other vehicles speed & the differential. Give it too early & it will mean nothing to them. Give it to them too late & well that's obvious.

You will give it when you are in the optimum zone at a time when they have not yet thought about moving out, you keep it on at a time they should be thinking about looking to come out. The fact it is on before they looked & remains on will concern them & they will have a double take. It still staying on will now provoke a response from them (brakelights are a good sign for you).
Don't get to them until you are happy , then release headlight flash & pass.

If you don't get a positive response on the appraoch (no easing off the drive by them, not adjusting position slightly away from the lane markings between you etc), do not go in there ! Expect them to pull out infront of you.

There will be times that you want to give it, but you are not quite "in the zone" yet to give it & the vehicle moves out. C'est la vie. Just match speed with them.

Whether I am still on the drive or not whilst giving the headlight flash will depend on the differential of my speed & their speed. If the differential isn't too big (ie I only have to adjust my speed by say 20mph if they pull out) I will still be on the drive on approach.
If the differntial is say 40mph, then I will be off the drive using acceleration sense while giving the headlight flash. If the differential is 70mph I will be doing smooth braking on approach while giving the headlight flash.

The headlight flash does not give me impunity to just go on regardless.

Times where I will give a headlamp flash are where there is open road in my lane ahead & if it wasn't for that vehicle potentially going to pull out, I would be accelerating firmly. If however I would already be off the drive in my lane because I was closing on something ahead in it. It would be churlish of me in such circumstances to attempt to persuade another to not come out.

I would also give it very early & long where I was travelling very quickly in lane 3 & there was a vehicle in lane 3 with absolutely no reason to be there beacuse lane 2 was completely clear & it was safe for them to be pulling into 2.

Notice I say safe for them to be pulling into 2. If there is potential for something to pull from 1 to 2 as I ask the one in 3 to go to 2, I wouldn't flash them, because I would be asking them to go to an area of potential danger.
Never do that.
For that reason I wouldn't give someone a headlamp falsh requesting them to move from 3 to 2 on the immeadiate approach to an on slip. This again would asking them to move in at a time of potential danger.

If despite your flash someone does pull out, just cancel the flash. It shouldn't concern you because you were expecting it & should be able to match speed. Always expect them to pull out.

If they hold don't forget to thank them with a raised left flat hand as you pass. If you don't they may not be so obliging next time.

Use it well & intelligently it will aid your progress without you looking aggressive.
Do it at the wrong time or the wrong circumstances it will make you look like an aggressive maniac.

It is a skill of it's own & you need to be fully aware of when & where to use it as well as when & where not to.

Don't try it on your own without first having some expert tuition in it.
A little knowledge can be a dangerous thing.

[Jon M]

Wow - never realised it was such a precision technique thanks for the detailed post vonhosen - probably good advice not to try it without instruction!

[JamesAllport]

Von Hosen's post brings out an important point that I fear is under appreciated: Civillian advanced driving, even to RoSPA Gold is only "entry level" advanced driving.

There is a world more to do. And the very best exponents of it are still the instructors teaching on the advanced courses in police driving schools. Because with the best will in the world, even if I'm willing to risk my licence (and I've stuck my neck out far enough on another thread this week to say no more ) I don't drive in national speed limits at 3 figure speeds, five days a week.

Nor do I have experience of "catching" an associate who is about to do something stupid at those speeds.

The police instructors do. That's why I get so wound up by "holier than thou" IAM observers. Most of them don't even know how much they've got to learn.

James