The Altima is Nissan’s best-selling vehicle and was the No. 2 selling car among all nameplates last year. Over its 20-year lifespan, some four million have been sold. The redesigned fifth generation 2013 Altima builds on that success.

Nissan says the new Altima is the most innovative yet, and the new model will begin arriving at dealerships next month. You might wonder why, when the Altima has been so successful, Nissan would redesign it. The answer is simple: sit still in the car business and people will beat a path not to your door, but right past it. Car companies are launching lots of new models, and Nissan is no exception. The Tennessee-based company plans five new models in the next 15 months: the Altima, the Pathfinder and the Sentra, as well as a hatchback and a crossover to be named later.

Built in Tennessee, the Altima competes in the midsize sedan category, which is arguably the most hotly-contested group with names like Camry, Accord, Fusion, Sonata and Malibu.

If mileage is one of the top reasons people choose a vehicle, the 2013 Altima 2.5 has the advantage with its estimated 38 miles per gallon on the highway and 27 mpg in the city. And if you use that estimate and do the math with the Altima’s 18-gallon fuel tank, you get an astounding range of more than 600 miles on a tank of regular unleaded gas.

If price is one of the top reasons people choose a vehicle, the 2013 Altima with the 2.5-liter 4-cylinder costs $21,500, or about $200 less than the 2012 model. The 3.5-liter 6-cylinder starts at $25,360. The two engines are mated to continuously variable automatic transmissions, and they’re the powerplants in seven Altima models: 2.5, 2.5 S, 2.5 SV, 2.5 SL, 3.5 S, 3.5 SV and 3.5SL. The 2.5-liter engine develops 182 horsepower and 180 lb.-ft. of torque, while the 6-cylinder bumps the horsepower to 270 and the torque to 258.

Meanwhile, you don’t mess around with the launch of your redesigned top-selling model, and Nissan will be pulling out all the stops this summer as it introduces the 2013 Altima. The company plans a wide range of advertising in what it is calling its “biggest launch ever.” Auto journalists were invited to Nashville last week for a daylong test drive through the Tennessee hills.

The Altima gets a number of new technologies for 2013, including a standard advanced drive assist display that puts key information on instant mileage, the audio system, a trip computer and turn-by-turn navigation in a 4-inch display right in front of the steering wheel. Tire pressure monitoring is also displayed, and Nissan takes the mandatory monitoring to the next level with its Easy Fill Tire Alert function. When the driver starts filling a tire after a system alert, the hazard lamps flash to let the driver know the system is functioning. When the tire reaches the correct pressure, the horn beeps. It’s a neat feature that eliminates the need for fumbling around for a tire pressure gauge.

The Altima also has hands-free phone and streaming audio via Bluetooth, a new blind-spot monitor and lane departure warning system that works off the rearview camera, available remote starting, and smartphone integration via the Nissan Connect system.

Inside the cabin, Nissan engineers used NASA research to develop the front bucket seats. Nissan says the “zero gravity” seats deliver a proven increase in blood flow, decreased muscular load and lower fatigue. We don’t know whether our blood flow was increased, but on our daylong test drive, we found the seats supportive and comfortable, and fatigue was not a problem.

The 2013 Altima has not yet been safety tested, but has warning systems for blind spots and lane departure, as well as a moving object detection system that warns the driver when anything is moving behind the car. All three systems work off the rearview camera, which is less costly than other radar-based systems.

With its new technology and features, best-in-class mileage and attractive pricing, the 2013 Nissan Altima will be on lots of test drive lists when it hits showrooms this summer.

If you’re in the midsize sedan market, it should be on yours too.

STATISTICS

Engine: 2.5-liter and 3.5-liter

Transmission: CVT

Horsepower: 182 and 270

Base price: $21,500 and $25,360

EPA mileage rating: 27 mpg city / 38 mpg highway (4-cylinder), 22 mpg city / 30 mpg highway (6-cylinder)