[jjshabado]

I take the sliding scale approach. If I get the food within 30 minutes I tip 25%, if I get it within 45 minutes I tip 20%, if I get it within an hour I tip 15%, If I get it over an hour and a half later they literally get the bill rounded up to the nearest dollar.

Obviously I adjust based on size of order and type of food (ie. I expect pizza/fast food a lot faster then when I order meals from a 'real' restaurant).

I'm with everybody else and say the car doesn't matter.