Dipped beams at 120kmp/h - safe ?

Motorist

You should be able to stop within the distance you see to be clear. At night, this means the distance illuminated by your headlights. "Dipped lights will let you see for about 30 metres and a car travelling at 100km/h will cover this distance in approximately a second."

Travelling at 120kmp/h in the rain - reaction distance is around 16.7m, stopping distance is 111.1m giving a total distance of 127.8m.

According to stopping within the distance you can see to be clear, you would have to be travelling around 60kmp/h on a motorway with dipped beams. I think it would be more dangerous driving at 50-60kmp/h but seems driving on blind faith is sometimes a necessity.

clanpiper

The speed limit signs should be read as 'The maximum permissable speed in perfect conditions for that stretch of road'. Driving at night is deemed not to be perfect conditions if there is a reduction in light (i.e. no artificial lighting). You should be reducing your speed accordingly.

If an accident was to happen one of the first things to be looked at is the speed you are driving at to ensure the road is clear within your vision.
Driving on a well lit motorway when the road ahead is seen to be clear it may be safe to do 120kmh. Where there are no lights except from your own car you should reduce your speed accordingly.

DylanII

Motorist wrote: »

You should be able to stop within the distance you see to be clear. At night, this means the distance illuminated by your headlights. "Dipped lights will let you see for about 30 metres and a car travelling at 100km/h will cover this distance in approximately a second."

Travelling at 120kmp/h in the rain - reaction distance is around 16.7m, stopping distance is 111.1m giving a total distance of 127.8m.

According to stopping within the distance you can see to be clear, you would have to be travelling around 60kmp/h on a motorway with dipped beams. I think it would be more dangerous driving at 50-60kmp/h but seems driving on blind faith is sometimes a necessity.

If Im on a motorway in the night time and there are no cars infront of me then I will put on my full lights. Depending on the specific motorway I may also have to switch them off when a car is approaching on the other side and when there is a break in the hedging.

Rothmans

Its not that unsafe at all IMO. Because, you're going on a straight, excellently paved road and you're not going to come across any pedestrians or cyclists. The only thing that you're going to come across on a motorway other than yourself is other cars, which you will see up to hundreds of meters away due to their red rear lights.
Also you will be able to see the road ahead of you up to 100m handy IMO due to proper cats' eyes on the Motorway.

TheChizler

Rothmans wrote: »

Its not that unsafe at all IMO. Because, you're going on a straight, excellently paved road and you're probably not going to come across any pedestrians or cyclists. The only thing that you're probably going to come across on a motorway other than yourself is other cars, which you will probably see up to hundreds of meters away due to their red rear lights.
Also you will be able to see the cats eyes ahead of you up to 100m handy IMO due to proper cats' eyes on the Motorway.

FYP

Carraig Fhearghais

Rothmans wrote: »

you're not going to come across any pedestrians or cyclists..

I have seen both on motorways! (at night & unlit/no hi-viz), as well as various wildlife from badgers to horses and debris spilt from lorries/trailers, all of which can cause a major incident!

Theoretically there should be nothing else on the motorway, life isn't theoretical though.

Victor

Rothmans wrote: »

cars, which you will see up to hundreds of meters away due to their red rear lights.

And if the vehicle has broken down?

Rothmans

TheChizler wrote: »

FYP

Not only probable, a near certainty. You're describing driving conditions on a road, not a Motorway.
You're last point is just spliting hairs to be quite honest.

Carraig Fhearghais wrote: »

I have seen both on motorways! (at night & unlit/no hi-viz), as well as various wildlife from badgers to horses and debris spilt from lorries/trailers, all of which can cause a major incident!

Theoretically there should be nothing else on the motorway, life isn't theoretical though.

Theoretically speaking, but you could see that (and are much more likely to see that) on roads, and it should be dealt with in the same manor as you would deal with it on the road.

Victor wrote: »

And if the vehicle has broken down?

Like above.
It will almost definitely be on the hard shoulder (which is what the hard shoulder was designed for). Otherwise, under/overtake depending on which lane it is in.

TheChizler

Rothmans wrote: »

TheChizler wrote: »

FYP

Not only probable, a near certainty. You're describing driving conditions on a road, not a Motorway.
You're last point is just spliting hairs to be quite honest.

So, to borrow from another poster, wild animals, broken down cars, debris, people driving with broken or inactive lights only happens on roads, not motorways?

I like to drive under the assumption that at some point, someone has built a brick wall up ahead.

Rothmans

TheChizler wrote: »

So, to borrow from another poster, wild animals, broken down cars, debris, people driving with broken or inactive lights only happens on roads, not motorways?

I like to drive under the assumption that at some point, someone has built a brick wall up ahead.

I find it pretty pointless to debate with people who put words in your mouth. If you read it properly, you might be a little less confused.

TheChizler

Rothmans wrote: »

TheChizler wrote: »

So, to borrow from another poster, wild animals, broken down cars, debris, people driving with broken or inactive lights only happens on roads, not motorways?

I like to drive under the assumption that at some point, someone has built a brick wall up ahead.

I find it pretty pointless to debate with people who put words in your mouth. If you read it properly, you might be a little less confused.

Ya...

The point is OP, be able to stop within the distance you can see to be clear!

Rothmans

TheChizler wrote: »

Ya...

The point is OP, be able to stop within the distance you can see to be clear!

'Ya' indeed. :rolleyes:

Motorist

Rothmans wrote: »

TheChizler wrote: »

Ya...

The point is OP, be able to stop within the distance you can see to be clear!

'Ya' indeed. :rolleyes:

I think we take all reasonable steps to mitigate risk in driving. But when it comes down to it, certain assumptions are made also. I find it a little disconcerting dimming my lights when travelling at 120kmph. But the danger is obscure as evidenced by the safety statistics of motorway driving.

The only cases that come to mind are that of some drunk man from swords who wandered into lane 2 in pitch darkness (he unsuccessfully tried to sue several different parties for his foolishness and recklessness) and a recent case involving an off duty garda.

The RSAs message of expecting the unexpected is a platitude in cases where youre driving under the assumption no hazards will be on the roadway ahead.

Wishbone Ash

DylanII wrote: »

Depending on the specific motorway I may also have to switch them off when a car is approaching on the other side and when there is a break in the hedging.

Just bear in mind that truck drivers sit much higher up than typical car drivers. The hedge may block their lights from you but your lights may be irritating them without you realising it. Hence the reason why many truck drivers (illegally) fit additional lights to the top of the cab.

Rothmans wrote: »

.......and you're not going to come across any pedestrians or cyclists

Have you travelled much on motorways? Take a spin any day on the M50, M1 or M11 and you'll see pedestrians, hitchhikers, cyclists, joggers, dog walkers, (slow) tractors,mo-peds, horses, dogs, foxes, badgers etc.

A motorcycle may legally travel at 50kph on a motorway. It will have one small rear light. That light may be dirty and not that visible in wet weather. Don't over estimate the safety value of red rear lights.

Rothmans wrote:

The only thing that you're going to come across on a motorway other than yourself is other cars

Presumably you meant "vehicles". I've yet to see a car-only motorway.

Del2005

Wishbone Ash wrote: »

A motorcycle may legally travel at 50kph on a motorway. It will have one small rear light. That light may be dirty and not that visible in wet weather. Don't over estimate the safety value of red rear lights.

Just to point out. The 50km/h is the minimum speed the vehicle has to he able to do, there is no law requiring it be done, you can legally drive at 1km/h on a motorway. It's not like they ever enforce vehicles not capable of doing 50km/h on a motorway anyway.

Rothmans

Wishbone Ash wrote: »

Have you travelled much on motorways? Take a spin any day on the M50, M1 or M11 and you'll see pedestrians, hitchhikers, cyclists, joggers, dog walkers, (slow) tractors,mo-peds, horses, dogs, foxes, badgers etc.

Fair enough, but first of all that's illegal, and secondly any of the above mentioned are unlikely to interfere with the OP's driving as they'd be in the hard shoulder.

WRT wild animals, you're just as likely to see them on any other types of road.

Wishbone Ash

You're undermining your own arguments!

Rothmans wrote: »

first of all that's illegal

Indeed - but that doesn't mean they don't occur. Do you drive under the premise that all others actions are above board?

and secondly any of the above mentioned are unlikely to interfere with the OP's driving as they'd be in the hard shoulder.

Not when they are crossing entry/exit points. And animals don't recognise the difference between the hard shoulders and carriageway.

WRT wild animals, you're just as likely to see them on any other types of road.

Absolutely - but you inferred that motorways were safe and that the only thing you will encounter are other "cars".

Rothmans

Wishbone Ash wrote: »

You're undermining your own arguments!

No I'm not. The first sentance which came I said is the following -

Rothmans wrote: »

Its not that unsafe at all IMO

Do you see the emphasised word there? I wasn't saying that the OP would be absolutley free from danger when driving 100km or so on a Motorway at night.Just that it wouldn't be that unsafe.
You know the seldom occuring instances of animals darting across the road, or wreckless pedestrians/ cylclists (who are almost certainly goin to be apprehended by Gardaí), they are examples of what can make a motorway unsafe.
I said that the OP wouldn't have to deal with cyclists or pedestrians because he almost certainly won't have to. I did not mean that never has it happened in the history of the world ever. Its extremely unlikely to interfere with the OPs driving if it ever occurs in his presence.

Wishbone Ash wrote: »

Indeed - but that doesn't mean they don't occur. Do you drive under the premise that all others actions are above board?

Not when they are crossing entry/exit points. And animals don't recognise the difference between the hard shoulders and carriageway.

I've agreed with Carraig Fhearghais that you may see animals on any road regardless of its classification (thats just common sense tbh), and out of that you have somehow managed to manufacture that I think that animals only use roads with hard-shoulders. Additionally, when I said cars earlier you nit-picked at that too to make me look stupid.
To clarify,(although a bit of common sense really ought to tell you) that, when I said that the OP would see other cars on the Motorway, I did not mean that he would exclusively see other cars only, but (again, a bit of common sense wouldn't go astray) cars and other mechanically-propelled vehicles. To reiterate, I did not mean to imply that motorways are for the exclusive use of cars. . . . if you could sell common sense in a bottle :rolleyes:

I don't assume everyone on the road is acting within the law, but I don't drive over-cautiously because of this, a bit of common sense on the road when driving is sufficient. 50 km/h on a motorway is a ridiculously slow speed. Legally it may be the correct thing to do, but common sense should tell you otherwise. At that speed you are far more likely to cause an accident than prevent one. Motorway are built for safe speed. If you want to drive that slow, you should stick to regional roads tbh.

Absolutely - but you inferred that motorways were safe and that the only thing you will encounter are other "cars".

Dealt with above.