Masatami Takimoto, Toyota Motor's executive vice president, came of age as an engineer with the law that set the standard for tailpipe regulation worldwide: the 1970 Clean Air Act amendments. Since 2003, Takimoto has led Toyota's R & D unit as it grapples with a more fundamental challenge than fighting smog: breaking the automobile's century-long addiction to petroleum.

Toyota emerged as an industry leader with hybrid technology, which it launched in the Prius in 1996 and now promises for every Toyota model by 2020. Now Takimoto's teams are exploring--and in many cases commercializing--several technologies, including advanced diesel engines, tiny battery-powered commuter electric cars, fuel cells, and a half-dozen kinds of hybrids. Technology Review contributing writer Peter Fairley caught up with Takimoto at the Geneva Motor Show last week.

Technology Review: How was the 1970 law so critical for Toyota research--and how do today's efforts compare?

Masatami Takimoto: The targets were very ambitious, and we just didn't know what we could do to meet these requirements. So as young engineers, we were told we could try anything, and that's what we did. In that sense, it was really unforgettable. Toyota actually developed eight solutions in parallel, then selected the one which we thought was the best. The solution which we and also some others chose--catalytic converters with a three-way catalyst--endures today.

It's very important when you do R & D to widen the scope, to have several competing technologies or systems, and then to choose what is best. Actually, this same approach was taken for Toyota's hybrid system. There are all kinds of hybrid systems: series, parallel, mild, full, et cetera. We started our hybrid development work in 1969, and since then, we've tried them all.

I was involved in the development of a hybrid system for a minivan that survived until the very end. This was a full hybrid system that was very close to what's called a series hybrid--totally different from the full hybrid that Toyota has right now.

TR: The same sort of competition seems to be happening today, with automakers commercializing a bewildering range of competing technologies.

MT: We've entered an age where the future of oil has become uncertain . . . So just like it was the case maybe 100 years ago, where you had different types of cars using different energy sources--steam engine cars, internal combustion cars, and very primitive kinds of electric vehicles all coexisting with the horse-drawn carriage--we have entered an alternative-fuels age.

We have to reinvent the car again because none of the alternatives are as appropriate for the automobile as oil. EVs [electric vehicles] are often talked about now as being the future car, but in my own opinion, the purely electric vehicle as a commercial product can probably only exist in the form of a very small commuter type of a vehicle. It's not universal.