Just the other day I was a passenger in a Peugot and it was raining very heavily. Cruise control automatically disabled when one of the tyres suddenly bogged down due to heavy water on the road causing the car to lurch.
Until these systems look at and analyse the road and traffic like we do, I see little hope in an automated system that wasn't deadly by design. For me the number 1 litmus test is to read the slope of the road: if about to go uphill- more gas required, about to hit a crest- back off and maybe allow engine braking.