I am a tour coach driver and am very concerned regarding the laws of a retarder.

The coach I am driving currently is fitted with a retarder but it is not in a working order. I did mention to the owner about the importance of the retarder but his reply was that I should use the gears at passes, the coach is automatic. It has only the service brake (foot brake).

What can I do regarding this matter and is there a law that prevent me from going on the road with the retarder not working, if there is a law against it, where can I get a copy to present it to the owner?


Definition of a retarder: A retarder is a device used to augment or replace some of the functions of primary friction-based braking systems, usually on heavy vehicles.

“Unfortunately legislation does not insist on any form of secondary braking – refer reg 149 attached.

I also called SABOA to see what their reaction was. Firstly they were not aware as to whether buses should have secondary brakes or not. Nor could they give any comment regarding voluntary lifting of safety standards within the passenger transport industry.

The fuel industry insists on vehicles having secondary brakes/retarders as part of their safety standards. Given the seriousness of bus accidents in SA, I feel there should be a similar standard for all busses over say 10 ton GVM

Regarding your reader’s situation I feel it’s absolutely criminal that an operator can allow a bus with a non-functional retarder to run on the road. What will happen if he has an accident? He will no doubt blame the brakes including the retarder. One should name and shame the owner.

The only thing that may assist the driver in this case is for him to look at reg 156 (1a) but that is a long shot as there is no requirement as with seat belts in a truck.”If fitted they must be worn”


 I am sorry I have nothing more positive but I hope this helps


I am almost sure that if a vehicle comes out fitted with a retarder, that it must not be removed and must be in working order. The fact that a coach has a retarder fitted and it is allowed to operate carrying people with it being out of order is inexcusable in my opinion.

Best regards

Patrick O’Leary



[A word of appreciation to our friends from Fleetwatch]

Also view:

Collision Investigation and Understanding Brake Failure

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