The biggest change for the 2001 Ford Explorer was the spinoff of the two-door Sport trim into its own Sport/Sport Trac line. While the Sport broke away to court the off-road, farm, and ranch market, the mainstream Explorer line continued to provide solid comfort and safety for families. Trim choices for the 2001 Explorer were XLS, XLT, Eddie Bauer, and Limited. The base engine for the XLS was the 4.0 liter, 160-horsepower V-6; the base engine for other trims was the 4.0 liter single overhead cam V-6 with a 205-horsepower output. A V-8 engine, with an output of 215 horsepower, was optional. Safety and comfort were both hallmarks of the Explorer brand, and the 2001 model continued to offer these in abundance. Buyers had a choice of four-wheel drive and real all-wheel drive options; another safety innovation was the Reverse Sensing System, which used sonar to signal approaching objects while the driver was backing up. Rack-and-pinion steering and a specially engineered suspension made the '01 Ford Explorer more agile than some of the other competitors for the SUV market. Gas mileage, though nothing to write home about, wasn't as dismal as for some other sport-utility vehicles of the era: 14-18 mpg city, 19-22 highway.