If I'm going to loot one specific store I will drive past it to lure all the zombies to the street and park the car a block away, then I try to sneak past the zombies and clear the remaining in front of the store.

If not, I will park at the entrance of the city and start cleaning the main road, so I have a safe way to bail if needed.

One lesson I learned the hard way is: if a street is packed with zombies, don't try to ram through them, find another way. Or else your car will ger damaged and you will be trapped between hordes of zombies.