Shredded Tires Silence BART Trains

At last, you can relax your ears when riding to the suburbs: BART is pursuing an innovative new scheme to quiet the notoriously deafening wheels.

A quarter of a million old rubber tires will be ground up and turned into shock absorbers as construction crews expand BART service to San Jose. The plan has plenty of fans, since it's cheaper than traditional shock absorbers, and makes use of materials that could wind up leaking toxic chemicals into the ground.

Similar re-uses have worked out very well. Early projects completed a decade ago continue to exceed expectations for wear and tear.

And although car-drivers may not realize it, they're helping to make the program a success. When you buy a tire in California, about $2 of the purchase price goes towards tire-recycling. Nearly three-quarters of waste tires are now diverted to secondary uses like athletic tracks and cement.

There's still a risk that the recycled tires may deposit harmful chemicals into the ground. Tests are still ongoing, although preliminary findings have indicated that there are no health effects on small organisms.

Unfortunately, commuters in the transbay tube won't reap the benefits of the new technology. The wheels in the tunnel will continue to produce ear-splitting shrieks for the foreseeable future.

Construction will start in 2012 on the line, and the completion date is still up in the air. It may be as late at 2025.