What is the use of Center High Mounted Stop Lamps(CHMSL) ?

mithun · 7th June 2006, 05:55

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 ???

nitinbhag · 7th June 2006, 10:30

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.

Rehaan · 7th June 2006, 10:38

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!

cya
R

Jay · 7th June 2006, 10:50

Quote:

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....

Rtech · 7th June 2006, 11:00

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.

nitinhegde · 7th June 2006, 11:10

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 ?

supremeBaleno · 7th June 2006, 12:50

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.

7th June 2006, 05:55	#1
mithun BANNED Join Date: Jan 2006 Location: Cochin Posts: 2,195 Thanked: 268 Times	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 ???
	() Thanks

7th June 2006, 10:30	#2
nitinbhag BHPian Join Date: Mar 2005 Location: Singapore Posts: 262 Thanked: 2 Times	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.
	() Thanks

7th June 2006, 10:38	#3
Rehaan Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 24,198 Thanked: 36,139 Times	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! cya R
	() Thanks

7th June 2006, 11:00	#5
Rtech Team-BHP Support Join Date: Apr 2004 Location: Bombay Posts: 5,765 Thanked: 371 Times View My Garage	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.
	() Thanks

7th June 2006, 11:10	#6
nitinhegde BHPian Join Date: Apr 2006 Location: ~ Posts: 242 Thanked: 91 Times	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 ?
	() Thanks

7th June 2006, 12:50	#7
supremeBaleno Senior - BHPian Join Date: Dec 2005 Location: Chennai / Kochi Posts: 5,676 Thanked: 2,919 Times View My Garage	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.
	() Thanks