They have blow molded plastic everything now. Gas tanks, fuel jugs, they even make blow molded highway barricades. Mini Indy even had blow molded plastic barriers designed for their outside wall. Wonder if someone could make rumble strips out of yellow plastic about 4 feet wide and 10 feet long and 3 feet deep that could be filled with sand and burried in the turns, then the grader operator could work up right to the rumble strips.

Honest Dad himself