They'll be driving on foam. Giant blocks of foam - known as expanded polystyrene -- are being used in construction projects across the Puget Sound, including the new State Route 99 ramps drivers ...

Sometimes, roadway workers deploy geofoam, blocks that are roughly 3-by-4-by-8-feet. They wrap them with a rubberized material to protect the foam for the long term, and then stick a concrete cap ...