The design is aiming at reducing the cost of creating
studs-not-on-top (SNOT) roads for LEGO towns, while keeping the
flexibility the SNOT technique gives us.
The present version has the road surface two bricks and a baseplate above ground level. The sidewalk is one plate above the road surface.
The baseplate may be omitted with the addition of a few extra pieces. The road surface can be lowered one plate, but it may increase the cost slightly.