Assign soldiers on bus to prevent zombie crowds in front to clean up a path.
Policemen, sof, sharpshooters....Every army unit has own features. Reasonably collocate battle arrays to greatly improve the rate to survive!
In addition, the bus which is properly upgraded will be more sturdy.

Features
-Many ways to collocate soldiers and wait for your commands.
-Upgrade bus and soldiers to easily resist zombie crowds
-Various charactered zombies for testing your tactics