Check the local zoning ordinance to see if the building height is measured from the grade to the highest point of the house, OR from the grade to the average of the roof's height.

Garage ceiling does not have to be spectacular height…might need a step somewhere inside, but easy enough to make up.

Who says the top of slab in the garage has to be level with the top of slab in the lower floor that is below grade?

@fissfiss and @3onthetree, you guys are genius, definitely can make the garage slightly shorter while still keep 8 or even 9ft ceiling in the rest of the first floor! will play around with that idea...

@Mark Bischak, Architect good call on the roof height, unfortunately we were planning to build a mostly flat roof in a modern style so I don't think this will help us much :(

Many times there is not only a height restriction, but also a limit on the number of stories.

Time to figure out the driveway and garage position. Maybe a driveway cross section. A 15 degree "slant" is >25% driveway slope which will not be allowed in many jurisdictions that require a gradual increase from 5% to a max 25% requiring more driveway length.

If you don't see this done already nearby, that's a sign.

So your driveway will be slanted down from the road to your garage? Make sure you have excellent drainage otherwise won't every hard rain flood your garage?