YOUNTVILLE, California — When the 2010 Toyota Prius goes on sale in May, Toyota expects to sell 100,000 of them in the remaining months of 2009, says Bob Carter, group vice president and general manager for Toyota Motor Sales, USA. In addition, the 2010 Toyota Prius will carry an EPA fuel economy rating of 50 mpg city/49 mpg highway -- the highest of any mass-produced car sold in the U.S.For the 2010 calendar year, Carter says the company plans to sell 180,000 units, which would put the Prius back on pace with 2007 sales after a 12.3 percent sales drop in 2008, with most of the decline coming in the dismal fourth quarter. The 2010 Toyota Prius starts production in late April at Toyota's plant in Tsutsumi, Japan.The third generation of the world's top-selling hybrid car represents a full redesign. The 2010 Toyota Prius is built on the company's global small car platform shared with the Toyota Corolla and , along with the Scion xB. Although the 2010 Prius has the same wheelbase as before, a wider track and a slightly longer body provide modest increases in passenger and cargo room. The car's coefficient of drag drops from 0.26 to 0.25.The major mechanical change on the redesigned Prius is the adoption of a 1.8-liter, Atkinson-cycle inline four-cylinder engine. Rated at 98 horsepower at 5,200 rpm and 105 pound-feet of torque at 4,000 rpm, the 1.8-liter is able to operate at lower rpm than the previous car's 1.5-liter inline-4 at highway speeds. Toyota officials say this is the single biggest contributing factor to the hybrid car's 4-mpg increase in EPA combined fuel economy (now 50 mpg). With an additional 36 hp coming from the 2010 Prius' nickel-metal hydride battery pack, total system horsepower is 134. Acceleration from zero to 60 mph is said to take 9.8 seconds, a half-second improvement over the second-gen car, while top speed is 112 mph, an increase of 9 mph.Standard equipment on the five-passenger 2010 Toyota Prius hatchback includes 15-inch alloy wheels with P185/65R15 tires, four-wheel disc brakes, stability control, a keyless ignition system, a tilt/telescoping steering wheel, automatic climate control, cruise control and a six-speaker, WMA-capable CD audio system with an auxiliary audio jack. Most options will be sold in packages. Beyond the expected JBL sound system, Bluetooth and DVD-based navigation system upgrades, you'll be able to get a supplemental ventilation system powered by roof-mounted solar panels, the Intelligent Park Assist system from the Lexus LS 460, the Lexus-based Pre-Collision system, and radar-based adaptive cruise control and lane-keep assist.Toyota has not yet announced pricing for the 2010 Toyota Prius.Inside Line says: Even in a down market with new competition from the 2010 Honda Insight, Toyota is confident the new Prius will win hearts, minds and monthly payments. — Erin Riches, Senior Editor