Emm what? If vehicles are somehow affected during blood moons, then should all the electrical stuff at your base, generators, turrets, traps, lights, your mining helmet light, battery light in your hand held flashlight etc, but that will cripple the gameplay and defensive options among other things.
madmole, please be considerate about major gameplay changing mechanics and if possible, it would be lovely if you don't force it on people, but have it optional under game settings, just like the horde night itself now is optional.
A17 already has seen a lot of stuff being cut out such as zombie looting, only 1 electrical light is craftable, a lot of paint tool textures have been removed as option to paint your base, food stat is totally gone from the game and food restores max stamina now.
I get that you want to move forward, it's your game, your vision of a zombie survival crafting game, but whatever you do, try to be gentle on forcing artificial limitations to players, because it's a creative game and let people be creative, if they want to drive their vehicles on hoard nights, let them, it does't force you to do the same play style as they do.
My suggestion to all of this is - if on hoard night you are on a vehicle, then make zombies spawn a bit in front of the vehicle and make them sprint and ram the vehicle, dealing significantly more damage than on usual days. With this, if you are skilled enough, you at least have the chance to avoid the sprinting zombie mob and it gives a challenge at the same time.