This is a paid asset, but now you can download Vehicle Garage/Showroom – Mobile Ready for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Vehicle Garage/Showroom – Mobile Ready v1.0
Garage environment for racing games, lightmapped and low poly.
Garage has low poly count and low draw calls. Most textures are 1024×1024, but there are a couple of 512×512 and 128×128 textures.
Poly count ~ 18k tris, Draw calls ~ 32.
Asset has a sample scene where you can see how garage looks and you can see optimal baking settings. You can bake with another lights but it’s preferable to keep those baking settings. Also, there is a script included which rotates a fan on the wall.
Car is not included in this asset.