As a new model for 2009, the Mercedes-Benz R320 BlueTEC clean-diesel crossover features a new AdBlue exhaust treatment system that delivers as much as 30 percent better fuel economy than traditional diesel. The roomy SUV also boasts a cruising range of more than 500 miles at highway speeds. So far, it has proven to be the greenest chauffered sedan available. The vehicle's base model retails for $47,650.

For an in-depth review of the R320 by LCT editor Martin Romjue, read Limo Vergnugen: LCT Reviews the Mercedes-Benz R320.

The clean-diesel SUV uses a technology known as BlueTEC that includes an oxidation catalyst and a maintenance-free particulate filter to reduce nitrogen-oxide emissions that are higher in diesel vehicles than gasoline engines. The BlueTEC diesels use a NOx storage converter in combination with an SCR catalytic converter and AdBlue injection to lower NOx emissions. The AdBlue system injects an aqueous carbamide solution into the exhaust flow, which releases ammonia and reduces nitrogen oxides to harmless nitrogen and water in the downstream SCR converter. About a quart of AdBlue is needed for every 600 miles driven, so the tank needs to be refilled after 10,000 miles during normal maintenance, according to the automaker.

The clean-diesel SUV uses a technology known as BlueTEC that includes an oxidation catalyst and a maintenance-free particulate filter to reduce nitrogen-oxide emissions that are higher in diesel vehicles than gasoline engines. The BlueTEC diesels use a NOx storage converter in combination with an SCR catalytic converter and AdBlue injection to lower NOx emissions. The AdBlue system injects an aqueous carbamide solution into the exhaust flow, which releases ammonia and reduces nitrogen oxides to harmless nitrogen and water in the downstream SCR converter. About a quart of AdBlue is needed for every 600 miles driven, so the tank needs to be refilled after 10,000 miles during normal maintenance, according to the automaker.

The R-Class cockpit features a four-spoke multifunction steering wheel with brushed aluminum accents on the lower spokes. The instrument cluster is designed with large chronometer gauges, and the console houses climate control and a new-for-2009 COMAND system featuring a large 6.5-inch display screen with a standard in-dash, six-disc CD/DVD changer and a Bluetooth interface that allows a phone still in a pocket or purse to be operated through the car's audio system. It can be equipped with an optional iPod/MP3 interface, Sirius satellite radio, HD radio and voice-activated controls.

The R-Class cockpit features a four-spoke multifunction steering wheel with brushed aluminum accents on the lower spokes. The instrument cluster is designed with large chronometer gauges, and the console houses climate control and a new-for-2009 COMAND system featuring a large 6.5-inch display screen with a standard in-dash, six-disc CD/DVD changer and a Bluetooth interface that allows a phone still in a pocket or purse to be operated through the car's audio system. It can be equipped with an optional iPod/MP3 interface, Sirius satellite radio, HD radio and voice-activated controls.

The COMAND system can play tracks stored on a data CD, DVD or SD memory card. The new system can also display maps and directions for the optional hard-drive navigation system, which can be set up with Sirius real-time traffic and Zagat restaurant ratings. The R-Class can be equipped with an optional rear-seat entertainment system that includes an integrated DVD player with dual-source capability, two eight-inch screens, wireless headphones and wireless remote controls.

The COMAND system can play tracks stored on a data CD, DVD or SD memory card. The new system can also display maps and directions for the optional hard-drive navigation system, which can be set up with Sirius real-time traffic and Zagat restaurant ratings. The R-Class can be equipped with an optional rear-seat entertainment system that includes an integrated DVD player with dual-source capability, two eight-inch screens, wireless headphones and wireless remote controls.

The R-Class can fit as many as seven adults. Cabin space represents 65 percent of total volume, and there's up to 40 inches between the first and second seat rows, with more than 30 inches between the second and third rows. The R-Class offers features such as reading lights, armrests, air vents and cup holders, as well as seat adjustments for each seat and two separate-source audio plugs. An optional MP3 media interface and dual-screen video entertainment system are available.

The R-Class can fit as many as seven adults. Cabin space represents 65 percent of total volume, and there's up to 40 inches between the first and second seat rows, with more than 30 inches between the second and third rows. The R-Class offers features such as reading lights, armrests, air vents and cup holders, as well as seat adjustments for each seat and two separate-source audio plugs. An optional MP3 media interface and dual-screen video entertainment system are available.

As new standard equipment on the 2009 R-Class, PRE-SAFE is a safety system that can sense an impending collision before it happens and take measures to protect occupants during the seconds before impact. The PRE-SAFE system that made its debut on the S-Class automatically tightens the front seat belts before a possible impact, and the front passenger seat moves to a position that can provide better protection. Side windows also close to provide better support for the window curtain air bags. If the system senses an impending rollover, the sunroof also closes.

As new standard equipment on the 2009 R-Class, PRE-SAFE is a safety system that can sense an impending collision before it happens and take measures to protect occupants during the seconds before impact. The PRE-SAFE system that made its debut on the S-Class automatically tightens the front seat belts before a possible impact, and the front passenger seat moves to a position that can provide better protection. Side windows also close to provide better support for the window curtain air bags. If the system senses an impending rollover, the sunroof also closes.