Please Don’t Use LED Bulbs in Halogen Reflector Headlights!

 I have some received some interesting comments from some folks at Facebook about LED headlights:

I got blinded by those f-ing headlights this morning on my way too work. Had to pull over for a bit. They should be illegal!!

They are not so good they blind oncoming traffic and cause more accidents and deer just freeze so you have to have good brakes to miss them

Are you kidding me?? Those LED headlights are too bright and have too much glare due to the high blue content. Blue light scatters much more than other light causing glare! How many other drivers need to get blinded to wreck and die so you can spot one deer in the road or ditch?!

I don't think that those people are trolls - I think they have been victims of LED bulbs in halogen reflector headlights. This prompted me to dig a little deeper and to write a detailed article on why you should never use LED bulbs in halogen reflector headlights. It seems like a cheap and easy upgrade and there are innumerable inexpensive bulbs available, but it's a terrible idea.

A few reasons:

  • You blind on-coming drivers with glare and scatter.
  • Your illumination is much worse than with halogen bulbs
  • The cut-off is horrible.
  • They’re impossible to adjust. 
  • You get a scattered burst of light as opposed to focused light. 
  • You look like a noob.

LED bulb in a halogen reflector headlight on the left side of picture - high power halogen on the right side of the picture. (picture provided by Ryland - see link below).

Please don’t drive with LED bulbs in halogen reflector assemblies. It’s just not safe, for you or for on-coming drivers. Plus you get terrible lighting, probably worse than your previous halogens.  If you want to use your existing headlight assemblies you should upgrade by using the most powerful halogen bulbs available - and don't forget to use a relay kit.

To upgrade to LED Headlights you need to buy complete headlight assemblies made specifically for LEDs.


In-Depth Technical Article by Daniel Stern, International Automotive Lighting Consultant and Audette Collection Friend & Advisor

Authoritative Study by SAE and RPI - January 2019
Society of Automotive Engineers (SAE) / Rensselaer Polytechnic Institute (RPI) Study
Citation: Bullough, J., "Investigating the Influence of Headlight Glare and Aim on Risk-Related Driving Behavior,"
SAE Technical Paper 2017-01-1360, 2017
Author(s): John D. Bullough
Affiliated: Rensselaer Polytechnic Institute

Detailed and well researched article by automotive design engineer - January 2019:

Older well researched article by automotive design engineer - October 2016:

More information on general lighting technology

    I'll publish more citations here as I come across them. This is not a controversial topic.