Been wondering about this. We know that most modern cars have their chassis in galvanized steel. The zinc coat on the steel sacrificialy corrodes to protect the steel.

However, I've been reading about a technique called "Impressed Direct Current" cathodic protection. This is where underground pipes and reinforced concrete bridges have their steel structures hooked up to the cathode of a direct current source. The anode of this direct current source is connected to a sacrifical metal. Something like titanium mesh is used typically, for longevity. Because the DC source "drives" the flow of electrons, the sacrificial metal need not be more reactive than the steel it protects.

Question is, does this apply to cars? We know that the chassis of the car is connected to the negative terminal of the battery (cathode), but I would have thought that this is primarily for earthing reasons.
Is added corrosion protection a side effect of this?