So, How fast should you drive with dipped headlights??

[Orionaut]

Consider this story..

https://www.dailymail.co.uk/news/ar...t-512575953&reply=512575953#comment-512575953

Now, while I agree with the overall sentiment, that Motorways (Especially "Smart" Motorways or ones with no hard shoulder) should be fully lit.

Nevertheless, the question is one I have been thinking about for a long time.

The problem is that if you apply the rule that you should only drive at a speed where you can stop in the distance that you can see to be clear, then really anything much over 30 on dipped lights is a No-no.

Driving above this speed is an act of faith. you are trusting that anything in your path is lit and that there is no "Dark Matter" (as it were) between yourself and the tail lights of the vehicle ahead.

Most of the time this is true

But not always....!

(Not just in the case of the story above, but on non-motorway roads one also has unlit pedestrians and cyclists to contend with)

So how fast does OCUK Motors feel is appropriate and safe for dipped headlight driving on unlit roads??

 

[BUDFORCE]

130mph.

 

[Maccapacca]

No one really expects there to be a black vehicle sideways in the fast lane on the motorway whilst its raining dark.

To be fair the car in the middle lane braked and swerved and he ploughed on through.

 

[wedrum]

Full whack race car

 

[Nasher]

70mph or lower.

 

[MatteH Oxford]

It was ******* it down with rain, the car in front slams the anchors on, so the best course of action was to maintain excessive speed for the conditions and overtake?

 

[Terminal_Boy]

Depends entirely on the performance of the dipped headlights. With a set of Philips Xtreme Visions, I can easily see my full stopping distance on dipped beam on unlit, unmarked rural roads at 60-70kph. On main beam, my Duster doesn’t go fast enough for there to be an issue.

 

[Terminal_Boy]

It was ******* it down with rain, the car in front slams the anchors on, so the best course of action was to maintain excessive speed for the conditions and overtake?

Yup, that was a terrible decision, but who expects to find a black car parked sideways in lane 3?

 

[Conscript]

It was ******* it down with rain, the car in front slams the anchors on, so the best course of action was to maintain excessive speed for the conditions and overtake?

My first thought too. That stranded car was almost invisible, granted, but the car ahead braking should have been a clue to be alert.

I'm spending a lot more time on unlit DC/motorways lately due to my parents moving, and have found that it's significantly more tedious than illuminated sections, so watching that is a little worrying. One thing that could improve matters would be if the central reservation blocked visibility of the opposing carriageway - that way, you'd be able to use full beam a lot more. I've found myself on the drive home several times with no one in front of me, so I switch on full beam, but have to keep dropping it due to traffic coming the other way. A lot of people don't even bother.

 

[vanpeebles]

Terrible driving. Typical BMW driving trying to dodge slower lanes.

 

[Lashout_UK]

I watch that and my first reaction is thinking that we would have all probably done exactly the same thing and ploughed straight into the other car. You see the other car braking, assume something is amiss in that lane (or perhaps he's slowing due to an unknown hazard in that lane only, such as standing water), so you watch that car and start to move out into the seemingly clear lane... *bang*

Even at 65mph, you're travelling more than the length of a tennis court per second – so it doesn't take much to suddenly be on top of that otherwise effectively invisible black car, particularly when you're taking into account things such as reaction time (even in the best of conditions).

Sometimes, these things are just effectively unavoidable – and that's when accidents happen. That black car seemingly becomes apparent (if you think about actually perceiving it and understanding what's going on) about two seconds before the driver hits it and, well, the average reaction time is probably in that range. The crash has already happened.

I say this in part because I experienced a very similar situation once and it was almost just blind luck that prevented me from ploughing into an abandoned car that was in the outside lane.

 

[Will Gill]

Terrible driving. Typical BMW driving trying to dodge slower lanes.

I don't agree with you

I watch that, and my first reaction is thinking that we would have all probably done exactly the same thing and ploughed straight into the other car. You see the other car braking hard, assume something is amiss in that lane (or perhaps he's braking due to an unknown hazard in that lane, such as standing water), so you watch that car carefully and start to move out into the seemingly clear lane... *bang*

Sometimes, these things are just effectively unavoidable. I say this in part because I experienced a very similar situation once and it was almost blind luck that prevented me from ploughing into an abandoned car that was in the outside lane.

I do agree with you

 

[Yaayuh!]

I watch that and my first reaction is thinking that we would have all probably done exactly the same thing and ploughed straight into the other car. You see the other car braking, assume something is amiss in that lane (or perhaps he's slowing due to an unknown hazard in that lane only, such as standing water), so you watch that car and start to move out into the seemingly clear lane... *bang*

Even at 65mph, you're travelling more than the length of a tennis court per second – so it doesn't take much to suddenly be on top of that otherwise effectively invisible black car, particularly when you're taking into account things such as reaction time (even in the best of conditions).

Sometimes, these things are just effectively unavoidable – and that's when accidents happen. That black car seemingly becomes apparent (if you think about actually perceiving it and understanding what's going on) about two seconds before the driver hits it and, well, the average reaction time is probably in that range. The crash has already happened.

I say this in part because I experienced a very similar situation once and it was almost blind luck that prevented me from ploughing into an abandoned car that was in the outside lane.

I concur.

 

[vanpeebles]

The lorry almost brakes to a stop, would that not be a good indicator that something isn't quite right?

 

[Rroff]

One problem I find - when you see drivers ahead of you braking you often come to a snap decision as to why and don't think beyond that - which throws you off if they are braking for another reason.

One I had was people braking just before and pulling to the right hand lane with a right hand turning coming up and I automatically assumed that was why and only belatedly realised it was because there was a cyclist (who was in the dark without proper lights and wearing dark clothes) just out of view - fortunately I managed to miss him.

I assume the forward collision warning/assist stuff on newer cars would help in situations like this.

 

[Lashout_UK]

The lorry almost brakes to a stop, would that not be a good indicator that something isn't quite right?

It's still going at a fair clip – it's not like it's just locked up and nosed the cab over – and you're passing it by that point; it's also not in your lane, so could again be reacting to something entirely unrelated.

Would anyone's natural reaction be to do a full emergency stop, in the rain, with perhaps something behind, just because of a slowing lorry? With the benefit of hindsight, perhaps. In the same situation, otherwise, you'd probably take it as a hint to perhaps slow and give it more room (which is what the driver effectively does) – but the last thing anyone would expect is an invisible car parked sideways across the outside lane. Too late, by that point.

I get where you're coming from, though, don't get me wrong – but I don't just don't think there was enough time, or enough room, for much else to be done in this particular case.

 

[danlightbulb]

The abandoned car is visible almost as soon as driver changes lanes. As its a dashcam recording, it likely also wont reflect what the driver should have been able to see at night. Conditions look poor but again, recording may not reflect the extent of the conditions.

Poor driving.

 

[Lashout_UK]

The abandoned car is visible almost as soon as driver changes lanes. As its a dashcam recording, it likely also wont reflect what the driver should have been able to see at night. Conditions look poor but again, recording may not reflect the extent of the conditions.
Poor driving.

That's about three seconds of footage, though, and the rest is the assumption. The driver might not have good night vision; they might have great vision. The dash cam might reflect the conditions far better than the human eye could, etc.

In any case, three seconds is probably about the going rate for reacting to what's ahead, and it's no doubt longer in some cases. After all, you're trying to process a very odd image – I've changed lanes, it looks clear, wait, is that actually a car, parked across the road, in my lane, that I'm now embedded in? Etc.

 

[Rroff]

The abandoned car is visible almost as soon as driver changes lanes. As its a dashcam recording, it likely also wont reflect what the driver should have been able to see at night. Conditions look poor but again, recording may not reflect the extent of the conditions.

Dascam recordings often don't mirror the actual visibility to the driver well but that can go both ways - mine has a software enhanced visibility filter on it - if the sensor is able to perform at all it will make things more visible in low light than they appeared in person.

That's about three seconds of footage, though, and the rest is the assumption. The driver might not have good night vision; they might have great vision. The dash cam might reflect the conditions far better than the human eye could, etc.

In any case, three seconds is probably about the going rate for reacting to what's ahead, and it's no doubt longer in some cases. After all, you're trying to process a very odd image – I've changed lanes, it looks clear, wait, is that actually a car, parked across the road, in my lane, that I'm now embedded in? Etc.

Yeah there is also other conditions in reacting in the realworld - you might for instance have a vehicle right behind you (which is another reason tailgaters need to die) that you can't not take into account in your thinking delaying your reaction and so on.

 

[vanpeebles]

It's still going at a fair clip – it's not like it's just locked up and nosed the cab over – and you're passing it by that point; it's also not in your lane, so could again be reacting to something entirely unrelated.

Would anyone's natural reaction be to do a full emergency stop, in the rain, with perhaps something behind, just because of a slowing lorry? With the benefit of hindsight, perhaps. In the same situation, otherwise, you'd probably take it as a hint to perhaps slow and give it more room (which is what the driver effectively does) – but the last thing anyone would expect is an invisible car parked sideways across the outside lane. Too late, by that point.

I get where you're coming from, though, don't get me wrong – but I don't just don't think there was enough time, or enough room, for much else to be done.

Personally, it's just the difference between aggressive driving and defensive. I'm a defensive driver so I'd have braked with everyone else and held my position. There is still a car in front of you for reference. Not to mention the road being unlit and chucking it down. If everyone in front is slowing/braking hard, why maintain your speed and look to overtake them all, they are braking for a reason.