Friction between your tires and the surface of the road is what stops your car, and friction is in short supply on wet or icy roads.
(friction; is; in short supply on wet or icy roads) (Friction between your tires and the surface of the road; is; what stops your car, and friction is in short supply on wet or icy roads)
friction Friction between your tires and the surface of the road
is is
in short supply on wet or icy roads
what stops your car, and friction is in short supply on wet or icy roads