Due to consumer interest and demand, the production of the 2006 Mercury Mariner Hybrid was pushed up a year to meet the demand for hybrid vehicles. The Mariner Hybrid combines electric motors and a 2.3-liter, four-cylinder engine to achieve an estimated fuel economy rating of 33 city and 29 highway. “Full” hybrid vehicles like the Mariner get better city fuel economy because they can run solely on the battery pack in low-load conditions, such as bumper-to-bumper traffic. In the case of the Mariner, the electric motors can power the vehicle to 25 mph, the threshold at which the gas engine is engaged. The 2006 Mercury Mariner Hybrid is basically a Ford Escape Hybrid with dressier trim.