Car exterior lighting regulations

I’m curious what the historical changes have been for changing USA-vehicle exterior lighting regulations?

IIRC side marker lights weren’t required until the late 60’s/early 70’s. Have there been other changes to the regulations over the years? I can only think of one other, the high mounted 3rd stop light, which seems like a good idea, around 1980 I think. What about reverse lights? And license plate lights?

Another curiosity, do most other countries follow the same exterior lighting rules? Colors for stop, signaling, markers, and differences front vs rear?

Early cars used kerosene lanterns for side and single tail lights and carbide headlights. The 1909 Ford Model T had a single rear kerosene light with a green light to the left, a white light to the right for the license plate and a red to the rear. No brake light!

Electric lights became common after electric starters were introduced (in 1912). Most cars still had single tail lights to the late 1940s and no turn signals into the early 1950s. Sealed beam headlights became required after WW2, I think. Quad headlights in the later 50s.

Not sure when backup lights became common or brake lights. Brake lights likely when 2 rear lights appeared. Side market lights in 1967, I think.

Rectangular headlights in the mid 70s and the current separate bulb and lens in the late 90s with halogen, HID and LED lights introduced over the last 25 years.

Other countries do not have the same convention for lighting. Headlights beam shape and sometimes color is different in Europe. France required yellow headlights late into the 1960s maybe? Different beam patterns in RHD and LHD countries. Side marker light colors differ as do taillight configurations in Asia and Europe.


Good summary, thanks. Does “quad headlights” mean a bright & dim for both sides?

Do you mean that all newer cars must have rectangular shaped headlights? I guess I’ve never noticed. Wondering what the motivation would be to regulate the headlight’s shape?

It means 4 headlights. 5 inch sealed beams, low and high beam.

No. Rectangular dual and 4 headlight systems became legal but not mandatory. You could still use 7 inch round duals and 5 inch round quads.

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1968 for side marker lights. I think (but im not sure) 1939 for sealed beam headlamps.

I had side markers on my 68 dart. That was the first year. Quad headlights were predominantly 1958 although desoto at least had them in 1957. I don’t remember a time when plate lights were not required. We had backup lights as an option in 57. As late as 61 Chevy only had them on the impala as standard. I think much of this developed as features not regulation. Minnesota has pretty specific candle power and height requirements for headlights though. May be based on feds or on their own

The ‘57 Mopars had twin headlights and twin driving lights, looked like quad headlights.

I don’t think they all did but I’m sure at least some did. My genius bil and I discussed it and I believe he said desoto at least on some models. He was a desoto fan and owned a 57 and as we waxed it, sure it only had single headlights.

Now in 1957, the neighbor kids dad was a body man at the Plymouth dealer. He made all the rest of us jealous because he made a go kart sized Plymouth for the kid, complete with a Maytag washing machine engine to power it. It was a 1957 model in fiberglass and had single headlights. Then the 1958 models came out and Danged if he didn’t add the quad headlights and changed the plate to 1958. Made us all mad some more, and wouldn’t give anyone a ride as he drove it around the block with his nose in the air. Memory of it is as clear or clearer than yesterday. At ten years old we we all car kids.

So to conclude, not all molars had quads in 57 but my bil would not be wrong either, so some did in 57.

They looked almost identical to quads, but the inside lights were driving lights, not headlights.

You haven’t noticed that many newer cars have LED headlights in an enclosure that conforms to the curvature of the vehicle’s front end?

This is what the front of my current car looks like:

Here is a view of the front of a different make and model:

I think there needs to be more regulation on lights…mainly headlights or front facing lights. More and more I’m seeing drivers with the obnoxious LED lights that are 10-20 times brighter then their headlights. One truck I saw had 3-5 LED light bars. I was so blinded I had to block the lights from his truck with my hand until he passed. Then I was seeing spots for a few minutes.


Agreed. My rear view mirror is flipped to the dimmed setting for more time than it is not while driving in the dark nowadays.

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There’s a pretty comprehensive set of regulations already in place that restrict forward lighting. My feeling is what we need is more enforcement of those regulations.

I run into the same thing you describe on a regular basis on the country roads around here.


The cheap LED bulbs make me want to take a tire iron to them. Some are even blue in appearance. That is illegal as heck.

And then there are squatted trucks that don’t readjust their headlights.


Not in NH or MA.

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CFR, DOT and SAE are related to FEDERAL regulations. They define almost all lighting regulations for vehicles regarding headlamps, turn signals, rear and side marker lighting. States have their own specific regs, including MA and NH. NH regulates things like this-

  • Red, blue, amber and green aftermarket lights and underglow are strictly prohibited.
  • Your license plate lights need to always be white.
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The law in NH mentions headlights. But there’s no mention if someone wants to add another/more lights.

The Mn stste patrol had a recent article in response to complaints on bright lights. 55 candle power was the headlight limit from all sources, two or four lights on. The height was a max of somewhere around 36 inches but I don’t remember the exact figures.

It seems pick up trucks are the biggest problem with the lights higher up than standard cars. So the closer they are, the more they are in your eyes. I think the ford trucks are the worst with four lights on even on low beam. I assume the still meet the specs though. No solution.

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Yes, I see that effect a lot. But my query was whether @Mustangman above was implying rectangular headlights were ever a code requirement. B/c I seem to see vehicles w/ round headlights quite often even now. Not related to LED headlights at all. My understanding at this point is rectangular headlights at one time were not allowed, but later became a legal option, but still not required. round still allowed…

I’m not aware of rectangular headlights ever having been banned. Can you cite a source for that claim?

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