Way back when this idea was new and everybody was complaining about Volvos, Greyhound buses in the US decided to see if keeping their lights on would cut accidents. Over the first year they had no accidents at all.
That is just from memory, however there's an authoritative report on this topic at http://www.swov.nl/rapport/r-97-36.pdf, which states that
Full application of DRL across all EU countries would... yield the annual prevention
of :
- 5,500 fatalities;
- 155,000 registered injured persons;
- 740,000 registered accidents;
- 1.9 million accidents involving insurance claims.
It also answers the OP's question:
The environmental costs, due to emissions of the 0.9% additional fuel
needed for the light energy of DRL, are of importance.
Since this report was written in 1997 however it is almost certainly considering tungsten lighting. The LED lighting used today should be at least 10x more efficient, changing the figure to <0.09%. Ex AA Series III LWB Safari - Gone
300TDi Disco (bought new - terrible car) sent back after 18 months
Freelander 1 Estate - leased, given back at end of lease
200TDi Disco (bought from a mate with 100,000 on the clock) - Gone
Disco 2 TD5 - sold and exported to France
FR2 TD4 GS - Gone
FR2 SD4 HSE - Now changed for a DS
New model ex-demo Evoque S 180 in white
Unable to order a new DS, so gave up. Now have a Volvo S90 Recharge.

I have no idea but as a round about sort of a guess:

Average running of 110kW engine at 70kW

Difference in tungsten to LED globes 70 watts saving.

30 mpg average driving.

70,000/70 = 0.1%

0.03 mpg saving changing to LED.

If 25% of your driving is at night then only 0.0075 mpg saving.

Also, the car has a smart alternator and generally charges the battery when power is not needed. i.e. coasting down hill. So the energy would have been wasted anyway, and maybe a tiny bit more braking on average would have been required which increases wear on the pads very slightly shortening their life by, lets have a guess, 1 day. Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18

I could understand the worry of DRL if you drive a Hybrid and battery life is everything

But you drive a LR you expect lower mpg and really need to worry about other things than DRL reducing mpg

Next you'll be stripping out any extra weight, maybe you could lose a wheel nut or two to gain a extra percent of mpg  Former Mod/Member, with the most post & Chicken George Arch nemesis

The biggest reason for DRLs seems to be aesthetic rather than anything to do with safety (where the evidence and available 'research' is as usual somewhat contradictory).
Where the reason for having DRLs is aesthetic then the cost of using it in terms of fuel, environmental impact and temporary blindness of others usually decrease to zero!

Hey guys.. some interesting comments, so thanks.
I tend to agree that DLR's have become little more than another piece of glitz to glamourise your 'wheels' and they certainly suit some front ends more than others.

As to safety aspect, it seems Kent has the most dangerous roads in UK with two major roads having the most accidents ever.
The multi pileup in fog on the Sheppey Bridge in 2013 showed the standard of driving we have to suffer so i still believe the best safety measure is to have Head Lights ON, but doubt the police would ever enforce it, seeing as they rely purely on cameras to catch speeders these days.

As far as accidents happen, most are within a 5 km radius of home. So I would think there are other issues which attribute to these accident far more than lights.

It's a long time since I have had an accident, but I fall well & truly into this category, 500 metres to 1.5 km! If I think back, car lights with these accidents would have made no difference at all. Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18

Oh Lightwater my friend.. not sure i can let that pass.
The sheppey bridge pileup with 100+ cars and lorries did in fact happen as people left the Island to go to work in the surrounding areas. So your accident stats do confer as to distance from home.

The newly opened bridge traverses a creek and one would expect some fog issues to be well known by the designers. However, built on the cheap it has no lighting or warning gantries and in the event, traffic hit a wall of fog at the summit and as the front cars slowed down, traffic coming up behind.. didn't.
With no warning gantry the carnage went on and on.. and on. surprisingly, nobody was killed.

However, we all know how to drive in fog and headlights and fog lights play an important part in being aware of those in front and behind, allowing a suitable distance to be kept. The inquest on this accident still has to fully find the cause, but as always it only takes one fool to cause mayhem.. especially if driving too close in fog with no lights.

I always do the Volvo imitation - dipped headlights all the time - do a lot of driving on small twisty country roads. Is a huge difference when you approach a tree lined corner and any oncoming traffic have their headlights on - can usually pick up their lights through the trees so you get better warning someone is coming the other way, or if traffic coming towards you when you are driving in to a low sun - can see them much better
So reckon if I can see them better with their lights on then in same situation others will see me much better


Didn't realise dealer can set lights to the Scandinavian option - will see about that next time is in for a service  Freelander 2
MY 2011
SD4 XS

As a newbie to the FL2 I have found these posts a revelation on how one car can be electronically tuned to so many options .. and many thanks to all who have commented.

Due to the poor standard of driving generally, I now drive with one eye on the road ahead to see where I'm going, one eye on the road itself to avoid numerous potholes and my third eye fixed on the nutter behind who tailgates me.

I now drive daily with headlights on purely so others can see me, in the vain hope that will give me enough chance to avoid them. Seeing as some drivers have a pathological hate of putting lights on before midnight, then hopefully street cred DLR's will make everyone more visible to everyone else... Amen.

I am sorry, call me old fashioned, but if you can not see a car coming towards you in the daytime under normal conditions without any form of lighting, then really, you should not be driving ......  MY2014 SD4 XS
Ipanema Sand

MY10 TD4-e GS Manual
Lago Grey Now retired after 8 trouble free years

Thanks for that .. With people like you on the road who obviously suffer the lights ON phobia, the rest of us best watch out for you . and we'll all steer well clear.

Bikes have headlights on permanently but they do not stop accidents.

I was riding along, headlights on, yellow jacket minding my own business but a car just pulled out from a side road in front of me.

Broken collar bone, broken shoulder blade, cracked ribs and 13 weeks off work!

Don't tell me lights are safer cos they aint, it's the drivers who don't look where they are going that causes the problems

As I said earlier, if you can't see what's coming in normal daylight, DONT DRIVE.  MY2014 SD4 XS
Ipanema Sand

MY10 TD4-e GS Manual
Lago Grey Now retired after 8 trouble free years

I'm sorry to hear that Scrimple.. I really am.

I'm certainly not going anywhere near the 'Bikers' vs Cars argument, ( especially why Bikers think it Ok for them to overtake at 80mph+ on motorways on the inside, instead of waiting in line like the rest of us .. . or why Cyclists think it OK for them to totally ignore red lights and zebra crossings while carrying no means if identification or insurance themselves )

But anything which makes the roads safer for us all cannot be a bad thing .. i wish you well.

Don't get me wrong, I am not against anything that improves safety, but I really do think we should shy away from expecting "DRL" to relieve us all of actually looking and driving responsibly.

There are many so called safety features like ABS that have made some drivers lazy, expecting the car to do the work for them and whilst in some cases it will, nothing really replaces attentive, responsible driving.

For example, what goes through peoples minds when they use their mobiles when driving, what makes them think it's OK? why do they think texting whilst driving is safe or do they really think they are better than everyone else and can do 2 things at once.

Sorry for the rant, but I see it everyday, if I were in charge, I would take their licenses from them.  MY2014 SD4 XS
Ipanema Sand

MY10 TD4-e GS Manual
Lago Grey Now retired after 8 trouble free years

no worries .. you have reason.

But you know what they say...

The one to watch most is the one in front of the one behind .. and the one behind the one in front.

and with the onset of 20mph zones maybe this is the way forward for absolute road safety ??