By 2020 or sooner, it is expected that there will be 1 billion cars and light trucks on the road. That's 25 percent more vehicles than we have today-one for every 6 1/2 people on the planet-says Joseph B. White, Detroit Bureau Chief of The Wall Street Journal. Aside from the obvious problems of roads to drive on, congestion, pollution and demand for petroleum products, disposing of worn out vehicles promises to become a major headache for automakers not all that far in the future.

That future will arrive especially soon in Europe. The traditional junk yard-where the American teenager of my day found serviceable and economical parts to keep questionable cars more or less operational-is about to go big league. Beginning next year, automakers throughout the European Union will be required to take back any vehicle they have made-regardless of its age and at no cost to its owner-and dismantle and shred it. Writing recently in The Wall Street Journal, Stephen Power says the End of Life regulations stipulate that automakers must recycle 85 percent of a vehicle's weight, and this will rise to 95 percent in 2015.

The EU law lets individual countries decide how close the take-back facilities-where cars are scrapped-can be to major cities and towns. The U.K., for example, requires that no car owner has to travel more than 30 miles to a take-back facility, and that 75 percent of owners should not have to travel more than 10 miles. Germany only requires that car owners not have to travel more than 31 miles.

A car brought to a take-back facility is first drained of all fluids, which are sent to a waste-treatment center for disposal in compliance with each country's environmental rules. Tires are removed and, if serviceable, resold as used. After air bags and seats come out, the remainder is smashed into a cube for a shredding plant, where shredded metal is separated for reuse.

When the End of Life legislation was moving through the European Parliament, automakers predicted it would be onerous. But, nearly 70 percent of a typical car is ferrous metal, and with the global demand for steel scrap pushing prices to all-time highs, compliance seems not likely to be as burdensome as it might have been.

Nonetheless, we can certainly expect similar legislation here in the United States, and probably sooner rather than later. The model for regulation in the United States tends to target specific substances, in contrast to the broad approach taken to recycling in Europe. So watch for more action like the recent national program to collect mercury switches from scrapped vehicles. Engineers can expect that their companies will increasingly call on them to design products for disassembly, and develop processes and methods for disposing of those products when they reach the end of the road.