Q&A

 Journeyman

If you find your ABS seems to be kicking in too soon on any slippery surface, consider looking at your tyres. What type of tyres are you using, all seasons or winter tyres? How old are your tyres? How much treadwear do they have, etc. ABS or not your car can only brake as well as the tyres on the car. If you have poor tyres for winter conditions, of course they are going to lock up sooner and cause the ABS to engage earlier.

the noise is normal in most cases. If there is a problem with your ABS the ABS light should illuminate on the dash to tell you. Be sure the light is operational though--do you see it come on breifly when you start the car? The noise you're hearing is the ABS pump motor and the jerkyness is the car using the pump motor to unlock the brakes as they lock up on a slippery surface.

ABS is a very good safety feature, but you have to understand how/why it operates in order to get the maximum benefit out of it. ABS will take longer to stop in some cases, but usually it will stop you just as well or even shorter than if you did not have it. However regardless of whether you take more or less distance to stop, with ABS you retain control of the vehicle, even with large/full brake pressure applied. That is really what the purpose of ABS is. It was not designed to necessarily stop you any shorter (though it does in most cases); but rather to let you keep control of the vehicle when one or more wheels locks up.

As always, in poor/slippery conditions drive with caution and leave lots of extra room for slowing down and manouvering, etc. ABS is not some kind of miracle that allows you to drive as if it were sunny and dry out in the middle of a winter storm.
hope help.