It feels like something's hindering motion a tiny bit but consistantly whenever it's on. Like pushing that "trac off" button allows the wheels to spin a little more freely, like the tiniest bit of pressure has been removed from the axles, or gears were oiled the tiniest bit. My main question is will it help me if I hit ice or black ice on the hwy? Does it really brake only the slipping wheel? Otherwise I'm great with leaving it off. Especially if it's impeding me just by being on. Thanks!

 

If the system is dragging the brakes, then something is broken and needs to be fixed. In a properly functioning system, having it on does not slow the car down.

That's a situationally dependent question. It can help in situations where you're applying more gas than your tires can put down on the given surface and you don't know how to control the throttle yourself (ie you feel the tire start to lose traction, but stay in the gas and let it rev to the moon anyways). That's not really a safety issue (accelerating too slow), but it is hard on the differential.

TBH the real safety concern with driving on ice is braking and turning - generally from people that don't have experience or understanding of driving in slick conditions who have overestimated their cars performance in slick conditions.

Certainly there's situations where you're already moving, hit a patch of ice, and can get one tire spinning a bit pulling the car to one side. No doubt thats a dangerous situation, but if the road is so slick in patches that are impossible to see that cause the tires to spin using the tiny amount of gas used to maintain speed, then the driver is already on the wrong pedal to start off with.