Dipping headlights on very open roads

bod1467

Joe_Horner wrote: »

Correctly adjusted dip beams are still at the angle they've always been. The problem is, an awful lot of cars out there don't have correctly adjusted dipped beams.

All I know is that I am noticing it a lot more these days than in years past. Perhaps the brighter lights are exacerbating an endemic issue with badly aligned lights? (A lot more cars these days have "driver-adjustable" lights - maybe they've been adjusted once and not adjusted back).

mcpitman

bod1467 wrote: »

All I know is that I am noticing it a lot more these days than in years past. Perhaps the brighter lights are exacerbating an endemic issue with badly aligned lights? (A lot more cars these days have "driver-adjustable" lights - maybe they've been adjusted once and not adjusted back).

I understand what you mean, I believe it is more due to HID/Xenon lamp technology.

Retorfitting HID's into reflector style headlights should be illegal, unless they are bulbs specifically designed for reflector lamps (H7R instead of H7 fitment).

Factory fit, should have self levelling suspension and headlight washers to avoid this.

forgotmyname

If you can see the lights of another vehicle then you should be on dipped lights.

Dont be one of those people that dazzle the oncoming vehicle as you think oh look there is a car coming towards me should i dip my beams.. lets think about it. Oh yes i will dip them. By which time the other driver is blinded by your lights.
If you see the lights of another vehicle apporoaching a bend then you should dip them before you blind them.

IamNotAllowedToUseMyName

Once people hit 40+ their eyes don't adjust as well as they used to. My night vision is perfectly fine, but bright lights dazzle me far worse than when I was younger.

Driving lights are a particular nuisance (and generally seem to be on for show as they make no real difference to forwards visibility in normal conditions).

Anyway, just because you think lights around you don't cause a problem don't assume that other drivers aren't being badly dazzled due to their particular eyesight issues.

Retrogamer

I try and make sure my headlights are on dipped by the time the other vehicle or it's headlights become visible.

Even if it is quite a distance it can still be very distracting or glaring depending on the car if it's driving towards you with full beam on.

If you struggle to see driving with dipped headlights on at night then best to buy better bulbs or visit an optician.
I can do 70mph easily with my dipped headlights and still see fine on totally unlit roads.

Rather than potentially blind oncoming cars like the OP here just switch to dipped and slow down slightly.

Joe_Horner

Retrogamer wrote: »

.
I can do 70mph easily with my dipped headlights and still see fine on totally unlit roads.

As pointed out on a recent thread, you may think you can but, if your headlights are aligned correctly then you really can't.

A low beam has a flat cut-off (plus a 15 degree angled bit up to the left) which, properly aligned, slopes down towards the ground at a 1:100 slope. The legal minimum dip for an MOT pass is 1:200.

That means that, past about 50m ahead of you, they're shining no direct light at all regardless of how bright they are. Anything illuminated beyond that is only getting scatter, reflection off the road surface, or whatever part of the left-hand "uptick" (which is less than 10% of the light's output) happens to find it.

That's absolutely nothing to do with the power of your lights, it's to do with the legally required pattern and height setting. Driving at 70mph with 50m visibility, when your reaction distance will be between about 20 and 40m at that speed, isn't "fine". It may feel like it is, but it just isn't!

Retrogamer

Joe_Horner wrote: »

As pointed out on a recent thread, you may think you can but, if your headlights are aligned correctly then you really can't.

A low beam has a flat cut-off (plus a 15 degree angled bit up to the left) which, properly aligned, slopes down towards the ground at a 1:100 slope. The legal minimum dip for an MOT pass is 1:200.

That means that, past about 50m ahead of you, they're shining no direct light at all regardless of how bright they are. Anything illuminated beyond that is only getting scatter, reflection off the road surface, or whatever part of the left-hand "uptick" (which is less than 10% of the light's output) happens to find it.

That's absolutely nothing to do with the power of your lights, it's to do with the legally required pattern and height setting. Driving at 70mph with 50m visibility, when your reaction distance will be between about 20 and 40m at that speed, isn't "fine". It may feel like it is, but it just isn't!

Are you sure?

The reason i ask is i'm using Philips X-Treme Vision +130%
They advertise that they are designed in such a way that they can increase visibility up to 130% further ahead of the car compared to OEM.

Either way at 70mph in pitch black i can stop within the distance i can see quite easily. That might be a combination of good brakes and tyres on top of that as well though.

Lights are aligned fine (MOT wise) and set to default setting on the adjuster in car

Joe_Horner

That's because a lot of OEM dipped lights won't even give meaningful illumination at the theoretical 50m point because they just run out of output.

Unusually, Wikipedia has a remarkably good technical article on headlights:

http://en.wikipedia.org/wiki/Headlamp

They show an illumination pattern for European (LHD) dipped beams giving light out to about 75m total, which corresponds to the MOT "minimum dip" of 0.5% below horizontal - which will cause flashing of other drivers over roads as bumpy as ours!

Also, bear in mind that because it's a flat-topped beam, the height of the illumination above the road reduces with distance, so they may be putting light on the road at 60m but the won't light anything higher than 2 or 3 inches above the road surface by then, which doesn't give you much to actually see and recognise!

The only ways to get usable light past the optical limits on low beam are to align the lights higher than designed or fit a bulb that's not specced for the lamp unit with the filament in the wrong place (like HID projector burners in reflector lamps). That changes the whole optic system and has the same effect - throwing light above horizontal - as misaligning your lights.


eta: On high beam, which is still a controlled beam but much more symmetrical and aimed horizontally, more output will, of course, mean further illumination but to double the range you'd need to quadruple the output at the filament and would probably melt your light units in the process!

Iceweasel

Most cars have a little thumb wheel with several settings for adjusting the headlights when the car has a full or partial load.

Lots of people never even touch it - (perhaps they don't understand what it's for) - so when they have passengers in the rear, or a load in the boot the lights are too high.

Those who are lucky enough to have Xenons should have auto-levelling lights.

Mankysteve

IF hes flashing you he letting you know your dazzling him so click over to dips.