1.   As technology improves, thereby making it possible to set a lower emission standard, new sources face increasingly more strict controls.

2.   And the additional power comes with lower emission levels and more fuel efficiency.

3.   Both the federal and California rules will require automakers to phase in the sale of models with much lower emissions from cars and light trucks.

4.   Companies can keep them or sell them and the program ends up helping companies make the transition to lower emissions.

5.   Nevertheless, DaimlerChrysler executives say they think natural-gas vehicles hold promise because of their high fuel economy, lower emissions and plentiful supplies of the fuel.

6.   The truck has lower emissions and better mileage than any diesel on the road, Ford says, because of a new technology called hydraulic launch assist.

7.   This provides better control over air intake for better performance, improved fuel economy and lower emissions.

8.   You can hoard them, or sell them, and it ends up helping companies make the transition to lower emissions.

9.   Environmentalists call that gap hot air, because the lower emissions were not achieved through greater efficiency or switching to renewable energy.

10.   Federal requirements for lower emissions and higher fuel efficiency also have helped push automotive electronics forward.