According to USA Today, hybrid car sales grew 81% last year.

"The lure of the Toyota Prius and other hybrid cars helped drive healthy sales of electric and alternative-powered vehicles last year, according to new data that shows the hybrid market has grown by 960% since 2000."

http://www.usatoday.com/money/autos/2005-04-25-hybrid-sales_x.htm

Hybrids represent less than 1% of the total car sales, but, if this 81% growth rate continues for five years, hybrids would have around 10% of the new car market.

As a relatively new technology, hybrids are only going to increase in fuel efficiency and power, increasing their overall value, and potentially accelerating their market penetration. So, even if fuel prices drop somewhat, the hybrid will become more competitive.

Coming up from the grassroots, biodiesel technology is fighting to free biofuel knowledge so it's accessible to the people. The significance of biodiesel isn't only that it can run a car on used fry oil, but that the development of the technology is consciously being placed in the hands of the people.

http://journeytoforever.org/biodiesel_make.html

Another interesting development is low-temperature diesel combustion. By burning the fuel at a lower temperature, emissions are reduced.

http://www.ca.sandia.gov/crf/research/combustionEngines/CIE.php

The other implication is that a lower-temerature combustion can enable the creation of smaller diesel engines.

According to the SJ Merc, the city of Stockton is using diesel-electric hybrids. This is a potentially minimal-emission, minimal-greenhouse, maximum fuel efficiency vehicle.

"Fuel economy is one reason. Stockton's hybrid buses are getting 4.9 mpg. That doesn't sound like much -- the five-seat Prius gets 60 mpg in city driving, according to the EPA -- but remember that buses seat 34 people, and regular diesel ones get only 3.3 mpg."

That's 34% better mileage. If they switched to biofuel, they'd reduce emissions, and the miles/per-ton-of-crap-in-the-air would drop precipitously.

http://www.mercurynews.com/mld/mercurynews/11476910.htm

The article neglects to mention the savings in brake dust emissions, a largely unknown pollutant, except to the people who do brake jobs. Brake dust is a tiny particle of dust that comes off brake linings. It's what turns wheels brown.

Hybrids stop the vehicle by removing the power from the motors, and attaching an electric load -- this turns the motor into a generator, that converts motion energy into electrical energy. The energy is stored in batteries. When it's time to accelerate from a stop, you take the stored-up energy to power the wheels.

Traditional brakes convert motion energy into heat and vibrations through brake-pad friction. The lost energy is never recovered, and some of it ends up chipping away tiny bits of the brake pad.

(They also don't talk about the possible collapse of fossil-fuel culture, but, that's out of the scope of this high-tech apologia for expansive modernization.)