Use of another vehicle as a proxy for a view

[Carbon Based]

How far would you go in considering another vehicle as an additional source of information?

A simple scenario would be a twisty country lane, with high, bushy hedges as common at this time of year. Visibly of the road ahead is likely to be just as far as the next bend. If following a high vehicle, such as a transit type van you may get an early indication of the direction the road takes.

Would you infer anything else?

What about turning left at a T junction or roundabout with multiple lanes? Due to those same hedges, no visibility of the road to your right is available as you approach. At the give way line is a stationary HGV in a lane to your right, indicating right.

Just before you reach the line, the HGV begins to move forward. Their road position is consistent with turning right and they have moved far enough into the junction to remove the possibility of actually taking a wide swinging turn to the left or otherwise encroaching on your chosen path.

Would you stop on the basis of not wanting to share the junction with them or go on the basis that, even though you have not been able to see the road to the right, any traffic approaching would have to hit and move the HGV substantially before it threatened you.

Finally, you are traveling at about 40mph on a gently twisty NSL road, with three cars ahead. The car nearest you has left a reasonable gap so you could potentially overtake. The car in front of that one is moving closer to the front car of the group of four, you suspect they are looking to retake too.

They move out for their overtake just as you consider moving out for yours. You are not overtaking the same vehicle. Due to the lead two vehicles approaching a left hand bend, you can't see what they can of the distant road ahead.

Given the distances involved, if the overtaking vehicle in front of you were to have got this badly wrong and came to an abrupt stop you would still be able to stop yourself but would be on the wrong side of the road.

Do you proceed or wait?

[TheInsanity1234]

I would probably just go with the HGV for the reason you've listed.

The overtaking issue, I'd rather make sure the road was clear and that I would be able to overtake safely, because different drivers have varying perceptions of what is safe and what is not, meaning the driver ahead may decide it's safe to overtake in circumstances you wouldn't take the risk in.

If I can't see ahead, I won't go. Simple as that.

[fungus]

I would probably just go with the HGV for the reason you've listed.

The overtaking issue, I'd rather make sure the road was clear and that I would be able to overtake safely, because different drivers have varying perceptions of what is safe and what is not, meaning the driver ahead may decide it's safe to overtake in circumstances you wouldn't take the risk in.

If I can't see ahead, I won't go. Simple as that.

+1

[true blue]

1) Transit van - sounds like a useful additional piece of information, but relatively minor really. I'd keep an eye on it, but I'm not sure I'd really get anything useful beyond what you described.

2) HGV / junction - I wouldn't necessarily look to go sneaking up the inside of the HGV, though may do so if there was a good amount of space. I would expect the view for any junction with two lanes to have opened out rather more than you describe, though I'm sure you could find examples to the contrary. I'm in general happy to use the fact that a large vehicle is blocking the carriageway to judge that it is OK to pull out, so long as I can finish getting out before the HGV has cleared the carriageway (after all - what could hit you?) Otherwise you risk conflict with someone who planned to 'just nip around the back of the heavy' and doesn't see you in time to stop. The only time that I think I apply this is turning left at a roundabout when a large vehicle is the next lane - I have no view of the road to the right, but know that the HGV will 'shelter' me for longer than necessary.

3) Overtake ahead - if I'd already had a long clear view of the road ahead the other overtake probably wouldn't stop me from mine. However, if I was relying on the view ahead for further assessment as I moved offside, loss of view would lead me to return to the nearside. Bit of a tricky one really, and not one I've ever encountered in practice.

As others have said, I wouldn't generally put myself anywhere without knowing the road was clear and confident that it would remain so.

[trashbat]

Someone here told me of the police's 'get in touch, stay in touch' maxim, which is a technique of keeping pace with a vehicle ahead and using its behaviour to predict hazards, where the road goes etc. Like many things, it's great until it isn't, so be careful what value you attach to it.

Your HGV example is potentially a bit short termist. The lorry goes, providing you with cover. You go too. As you complete your left turn and the lorry clears your lane to proceed in the opposite direction, you look in your RVM to see a vehicle closing on you at a high rate. You wouldn't have gone if you'd had a clear view.

[zadocbrown]

Re the overtaking - couldn't give a definite answer without being there. But in general it would depend very much on whether I trust what the other overtaking driver is doing. If their manoeuvre looks safe they will be clearing a path for me, but if they look to be heading into danger I would be dropping back in anticipation of an incident I don't want to be anywhere near.

[Carbon Based]

Thanks for the responses. As these are a bit hypothetical I can't post images/map references but it is still good to get everyone's input.

[WhoseGeneration]

Thanks for the responses. As these are a bit hypothetical I can't post images/map references but it is still good to get everyone's input.

There are no absolute rules for the situations you describe but, with observation, it will mean that you could take advantage in those situations.
Caveat, as always, a safe alternative for you.