drag

dragと言えば動詞で「引っ張る」という意味がすぐに想起されますが，名詞で「じゃま物［者］, 障害物」という意味があります（『プログレッシブ英和中辞典』小学館）。そして，とりわけ今回のように車に関係する文脈では「空気抵抗」という意味で用いられるのです（『プログレッシブ英和中辞典』同上）。co-efficientは「係数，率」（『新英和中辞典』研究社）という意味なので，with a much lower co-efficient of dragは「空気抵抗率の大幅に減少した」と解釈できます。（Koyamamoto）

Peugeot 208 HYbrid FE
The Peugeot 208 HYbrid FE lightweight concept car will be revealed at the Geneva Motor Show next month. No pictures are available yet, but Peugeot has confirmed that the supermini boasts a headline CO2 emissions figure of 49g/km and yet can complete the 0-62mph sprint in 8.0 seconds.
Built by Peugeot and oil company Total, the 208 HYbrid FE is designed to capitalise on the research conducted by both firms into better aerodynamics, weight saving and drivetrains.
Starting with the current Peugeot 208 1.0-litre VTi 68bhp, which emits 99g/km of CO2 and plods from 0-62mph in 14 seconds, the HYbrid FE will feature a more aerodynamic design with a much lower co-efficient of drag than the production model. Special tyres and wheels will contribute to reduce rolling resistance.
http://www.autoexpress.co.uk/peugeot/208/62795/peugeot-208-hybrid-fe