How about going out to dinner tonight? What kind of food? Chinese? Italian? French? Cars? Huh? Cars? I doubt that it will be anytime soon that we will be eating cars, but with the green movement, car manufacturers are working on organic materials to replace petroleum materials in your cars. How soon will that happen? How about now. There are selected organic materials in cars today.

Why don't you know about it? I'm a bit surprised that it isn't more publicized, but there are reasons to make it secret too. Ford has talked about it recently and more manufacturers should be joining. Of course, I'd suspect that Green Toyota will make a big deal about it soon.

I had a discussion with a friend recently who stated that all buildings are built to last "forever" and shouldn't be destroyed to put something new in their place. I pointed out that nothing is built to last forever and everything has a fixed lifetime. You can replace parts from time to time, but everything wears out either from wear or from environmental conditions. That applies to buildings and vehicles.

However with cars, what should the life of a car be? When should it start degrading due to the materials just starting to decompose? I don't think any manufacturer has been willing to state that they are building a car that eventually will fall apart. There are laws in Europe today that state that some high percentage of all parts in the cars can be recycled and each part is marked accordingly. But that is very different from having the parts just begin to decompose on their own.

Ford announced that they would start making some parts out of hemp. No, that isn't marijuana, it is industrial hemp. And, no, with the laws in the United States today, you can't grow that either, so it will have to come from outside the U.S. Also on the list are biodegradable glass-fiber replacements and soy bean based foams.

As I said, there are some small applications of organic materials in lots of cars today. For example, the smallest Mercedes (in Europe), the A-class uses a spare wheel undertray made from abaca, which is a relative of the banana tree. Moving up the scale of Mercedes models, the S-class has some 95 pounds of parts made from natural fibers and renewable materials. That includes the charcoal in the fuel tank vent filter which is made from olive pits. Moving to the other premium German car, the BMW 7-series, the door cards are made from wood fiber.

What about flax? Door cards, insulation, and lots of trim parts are made from flax these days. This includes the rear parcel shelf on the European Renault Twingo.

Goodyear is working with corn starch as a reinforcement instead of silica and carbon black in their tires.

Ford has announced that it will be using foams made from natural materials. The seat filler will be made from soy foam in the 2008 Mustang.

Soy foams are lighter than petrochemical products and the use of soy has historical precedence with Ford. Henry Ford had something of an obsession with the stuff. Ford's cars made in the mid 1930s used paint and trim parts made from soy. The company even made an experimental car with body panels made from soy. In 2003, Ford showed a concept car called the Model U that used natural fibers and soy-based materials.

But what about parts that you can see and touch? Sooner than you think, interior trim components and even body panels may be made of organic materials. Engineers today are working on using coconut husk set into a resin made from corn starch for panels. They are strong, light, and biodegradable. Ford claims that this material is very close to being used in production cars.

Natural fibers have many advantages over synthetic materials other than just being green. A small molded trim part made from Ford's coconut fiber material weighs 30 percent less than the same piece made from fiberglass. The raw material is renewable and the manufacturing process uses less energy than making the same part from petroleum-based synthetics.

This stuff is known as "coir". It is a by-product of coconut processing and is strong and cheap. The resin to bind it is made with polylactic acid, which is made from corn starch.

Other natural fibers can be used as well. Indian grass is even more effective because it disperses in the resin better. Ford is also experimenting with pineapple fiber.

The use of natural fibers isn't without problems. The first experimental soy foams smelled like cooking oil. Will this be the next "new car smell"? Not likely because they were brittle too. Another problem is that making natural fiber composites is a much slower process than using current petrochemical materials. For example, it takes about two minutes to make a small trim component with polylactic acid. The same part made with today's resins takes 30 seconds.

The big question, however, is durability. As I said before, what would your reaction be to a car that has a specified lifetime? Say 10 years -- or maybe 20 years? I doubt any of you will be buying a new car that you expect to keep for 10 years. But what would that do to the used car market and resale values as the car approaches the time it starts falling apart?

But that isn't the whole story. These parts don't just instantly fall apart when the clock strikes 10 years. They start degrading immediately after manufacture. So the solution isn't going to be organic composite materials that degrade by themselves. The current thinking is that the parts will be made from materials that don't degrade by themselves. They will be built with a wear lifetime matching the rest of the car, whatever that is. When the car is trashed, special microbes will be introduced to these parts which will start the decomposition process.

It appears, then, that it isn't likely that you will be offered car parts to eat in the trendy restaurants. But car manufacturers today are building cars with parts that have origins in the field instead of the oil well. This trend looks to continue with more parts having a natural origin in the future.