on a slab of concrete 12'x24' is about the standard for full-size trucks and suv's and older American cars i.e. Cadillac, Lincoln, Olds and Chrysler all had model years where they measured 18' on length. Two Car adage double the width plus 16" for the slab.
Don't forget the footing at the perimeter and steel plus forms when estimating slab costs and materials.
It would depend on the size of the one car garage and garage door opening.It depends on the size of the garage. Not all one car garages are the same size.
What is average size of two car garage?
It varies on what size car you plan on putting in it.
For your answer, I suggest you go to:http://www.apmbuildings.com/onecargarage.shtml
A two car garage is usally 24 feet X 24 Feet.
According to the DIY Network a 3 car garage is about 950 sq. ft.
Why would there be a minimum length? A garage could be 10'X10' but a car will not fit in it, I have a 22'X22' and a full size pickup will not fit in it, so it depends what you drive.
Average, 24' + 30'
A one car bay garage is usually a free standing structure with room for one car. They can be attached to a house.
16 by 7
There aren't any standard dimensions for a 1.5 car garage, but a one-car garage is less than 300 square feet. A two-car garage is usually just over 600 square feet, so a 1.5 car garage would be somewhere in between the two measurements.
A parking area for one car inside a garage.