by Scorpion0x17
My regular gaming group played and won Scenario 04 Drive-By Shooting without using any of the cars (not even sure we searched them!) a while back, and whilst we won because we had Dave in play and got the Molotov ingredients at the right time, I am sure that that scenario is entirely beatable without cars.So, no, any scenario with a car is not almost unwinnable.
However, jumping straight in a car and staying in a car, mowing down zombies, now that can make a scenario almost unwinnable, because you level up too quickly.