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Old 7th June 2006, 05:55   #1
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Wink What is the use of Center High Mounted Stop Lamps(CHMSL) ?

Nowadays, we can see a third brake light or a centrally mounted stop lamps in almost all the cars. Other than wasting some units of battery charge I've never found any use for it since most of the Indian cars are having a good sets of brake lamps suitable for both the day & night time driving. So what's the real use of it ?

But in North America since 1986, in Australia since 1990, and in Europe since 1998, a central brake lamp, mounted higher than the vehicle's left and right brake lamps and called a Centre High Mount Stop Lamp (CHMSL), is also required. In 1986, the United States National Highway Traffic Safety Administration and Transport Canada mandated that all new passenger cars have a CHMSL installed.

The Americans are having the logic that the CHMSL, which must burn steadily and is not permitted to flash, provides advance warning to vehicle operators whose view of the braking vehicle's regular stop lamps is blocked by interceding vehicles. The CHMSL also helps to disambiguate brake vs. turn signal messages, particularly in North America, where red rear turn signals identical in appearance to brake lamps are permitted.

I'm of the opinion that most of the rear collisions can be avoided if we never tailgates or always keep a safe distance with an eye on the road ?

So is CHMSL really help in reducing the rear collisions in the Indian scenario ???
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Old 7th June 2006, 10:30   #2
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Personally, I find the CHMSL quite useful.
Helps in bumper to bumper traffic when you cant really see teh brake lights of the car ahead, specially if it is a small car.
When SUVs ahead of you brake, it provides advance warning even when there are other cars in between.
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Old 7th June 2006, 10:38   #3
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I agree with Nitinbhag, the HMSL is REALLY useful.

Firstly, in stop and go traffic, especially if you are following a car in a SUV/Jeep or truck, its very hard to see the brakelights of the car in front of you.

Secondly, It has the advantage of being completely isolated, so when it comes on it is more eyecatching.

Thirdly, at night when the taillights of the car are on, it makes it easier to differentiate when the brakelights are or and not. (Some cars have pretty weak brakelights), and sometimes in heavy rain its hard to tell when the car in front of you has his brakes on (even if the brake lights are bright, since its difficult to tell the difference between brakelights and taillights in the rain).

Thats some good information in your post! I didnt know the HMSL was legally required in so many countries since so long!

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Old 7th June 2006, 10:50   #4
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Originally Posted by Rehaan
at night when the taillights of the car are on, it makes it easier to differentiate when the brakelights are or and not.
Exactly what i was thinking and also in Highway driving a CHMSL can easily be seen from long distances which is a hint/caution that you might have to brake at that point....
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Old 7th June 2006, 11:00   #5
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I find the CHMSL really useful in traffic and out on the highway. As Rehaan says, the positioning of the CHMSL is what grabs the attention first. Also, as most of these are LED's, they activate a bit faster than regular bulbs, which means the car behind has a fraction more time to react.
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Old 7th June 2006, 11:10   #6
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Just one more point : In India, I heard as per RTO regulations, you cannot have a brake light on Spoiler as well as have a CHMSL..is it true ?
I have seen many vehicles sporting both !

Also,I think OE's provide either of these and not both...Can somebody confirm ?
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Old 7th June 2006, 12:50   #7
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The Baleno Lxi (no spoiler) has the CHMSL, while the Vxi has it only on the spoiler.
But if a guy buys an Lxi and then fits an after-market spoiler, he could choose to retain both, though I feel it would be useless and infact confusing.

Last edited by supremeBaleno : 7th June 2006 at 12:52.
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