Low-Beam Physics

[WillRB]

Hey all, Hope you are okay?

 

Ive just been on reddit ranting about a certain situation and nobody seems to understand and has gotten very angry at me. so I'm going to do my very best to explain it here just to I know i'm not going mad.

 

Scenario: You are driving in your car at night up an incline with your low-beams on, you are reaching the top of said incline (still driving uphill) and over the top of the horizon you see an oncoming vehicle. As your low-beams are still running parallel of the incline, your lights will illuminate (blind) this oncoming vehicle and vice versa as you are below their low beam cut off height. 

 

I'm not annoyed that if happens because its just physics but I i'm just wondering why so little other motorists understand what is going on and then will flash you thinking you have your high-beams on.

 

This all came about when I was on a road yesterday with many inclines and I kept getting flashed by other motorist who most likely thought I had my high beams on. 

 

I hope this makes sense and if it doesn't I've made a questionably tacky illustration bellow. As you can see both cars have their low beam on (top of the illumination is parallel to the incline the car is on.) and in this case both cars would be blinding each other.

Edited 28 September, 2023 by WillRB

[MarkyG82]

Could well be the reddit users are intentionally winding you up or are just the usual reddit level of intelligence.  I don't get flashed for it much but I do experience the "phenomenon" often enough.

[indars]

1 hour ago, WillRB said:

Hey all, Hope you are okay?

 

Ive just been on reddit ranting about a certain situation and nobody seems to understand and has gotten very angry at me. so I'm going to do my very best to explain it here just to I know i'm not going mad.

 

Scenario: You are driving in your car at night up an incline with your low-beams on, you are reaching the top of said incline (still driving uphill) and over the top of the horizon you see an oncoming vehicle. As your low-beams are still running parallel of the incline, your lights will illuminate (blind) this oncoming vehicle and vice versa as you are below their low beam cut off height. 

 

I'm not annoyed that this happens because its just physics but I i'm just wondering that so little other motorists understand what is going on and then will flash you thinking you have your high-beams on.

 

This all came about when I was on a road yesterday with many inclines and I kept getting flashed by other motorist who most likely thought I had my high beams on. 

 

I hope this makes sense and if it doesn't I've made a questionably tacky illustration bellow. As you can see both cars have their low beam on (top of the illumination is parallel to the incline the car is on.) and in this case both cars would be blinding each other.

If lights are adjusted properly, there's nothing you can do- just drop your look to roadside for few sec til cars changes with each other- to avoid blinding. As for others- don't argue with idiots, people will not recognize difference between you. If you'll lower lights with screwing, in garage (or by knob in panel, for halogen type), you will see nothing on the straight level road. But others will be happy 😉 

[J.R.]

I bet you have LED or Xenon lighting.

 

There never was dazzling from oncoming cars on inclines before their adoption.

 

The diagram is incorrect because dipped beam lighting does not shine downwards to the extreme angle shown, well old school headlights never did, also the oncoming driver will be viewing the illumination from an angle and not head on which is much less dazzling.

Edited 28 September, 2023 by J.R.

[J.R.]

1 hour ago, WillRB said:

I'm not annoyed that this happens because its just physics but I i'm just wondering that so little other motorists understand what is going on and then will flash you thinking you have your high-beams on.

That does not make sense, did you mean to write "if" or "why" instead of "that" ?

[WillRB]

26 minutes ago, MarkyG82 said:

Could well be the reddit users are intentionally winding you up or are just the usual reddit level of intelligence.  I don't get flashed for it much but I do experience the "phenomenon" often enough.

I mean I was only trying to start a discussion but I guess reddit is not the place then maybe. Yeah it doesn't happen too often but enough. its no problem for me when it happens to me but find it interesting that some people may not understand what is going on.

[WillRB]

27 minutes ago, indars said:

If lights are adjusted properly, there's nothing you can do- just drop your look to roadside for few sec til cars changes with each other- to avoid blinding. As for others- don't argue with idiots, people will not recognize difference between you. If you'll lower lights with screwing, in garage (or by knob in panel, for halogen type), you will see nothing on the straight level road. But others will be happy 😉 

I mean you have said it perfectly here. I just found it interesting that some people don't see what's going on and that there nothing realistically that anyone can do about it. On the motorway you see some cars with their headlights pointed so far down they can see about 10 meters in-front of them, like you say I guess they are keeping other road users happy.

[WillRB]

28 minutes ago, J.R. said:

I bet you have LED or Xenon lighting.

 

There never was dazzling from oncoming cars on inclines before their adoption.

 

The diagram is incorrect because dipped beam lighting does not shine downwards to the extreme angle shown, well old school headlights never did, also the oncoming driver will be viewing the illumination from an angle and not head on which is much less dazzling.

I totally agree with you and definitely the LED and Xenon's do no help at all. 

Sorry about the diagram I know its not too accurate but I just didn't know how to explain it 😂

[WillRB]

29 minutes ago, J.R. said:

That does not make sense, did you mean to write "if" or "why" instead of "that" ?

If you are referring to the first 'that' then swap it for 'if' and if you are referring to the second 'that' swap it for 'why'

Apologies