The WizKids site prints it out a little small, so people at my venue weren't sure whether or not you can squeeze two vehicles into the "street" facing short-way. Can you?

The templates on the Wizkids size have the correct size, you just have to uncheck the "shrink to fit" option when printing.

The gap in the B4 template is exactly 3 inches wide.
A vehicle base is 1.5 inches wide.
So yes, you can fit two vehicles in.