Driving Down the Road: 2009 Volkswagen Jetta TDI

Diesel is not what it once was. If your association with Dr. Rudolf Diesel's namesake engine includes the words "underpowered", "slow", "noisy", "smelly", or "sooty", you need to be brought into the 21st Century.

Modern diesels, as exemplified by Volkswagen's latest, in the 2009 Jetta TDI, are none of the above. They're clean, quiet, and powerful. Except for four wheels and a Volkswagen badge, a new Jetta TDI is not at all like an old Rabbit Diesel.

Diesel is undergoing changes analogous to those with gasoline and gasoline engines over thirty years ago, when...