well indeed you can drive a car "better" after a spliff then after a bottle of wine.
But surely on both you shouldn't be driving a car. If anything will happen and they will make a drug tests or alc tests you are fuc&*#
AND if you are really unlucky and someone will die in an accident and you was "high" or "drunk"...
You are going to jail.
Is it worth a risk?? I am suuuure it is not.