With the cost of gasoline at about $4 a gallon in most of the U.S., fuel efficiency is a buzzword for the auto industry. Each year, manufacturers expand their fuel-efficient product lines, giving consumers more options to help save money at the pump without sacrificing vehicle preference.

Recently NADAguides, a publisher for vehicle pricing, came out with its annual list of the most fuel-efficient vehicles of 2011. The data are based on combined miles per gallon (MPG) and the average rate of city and highway’s MPG. The study names the most fuel-efficient vehicles in multiple categories, including sedan, luxury, and hybrid. Each vehicle segment offers models that achieve at least 23 or more combined MPG, including the (traditionally gas-guzzling) SUV and crossover segments.

Click ahead for the 2011 model year’s most fuel efficient vehicles.

By Jill Weinberger
Posted 13 June 2011

2011 Kia Sorento 2WS 4 dr I4 LX
Combined 25 MPG, MSRP: $22,595

According to NADAguides, consumers who are looking to downsize from a full-size SUV, but still take advantage of the space a large vehicle offers, the crossover gets the job done. The Sorento offers a 2.4-liter four-cylinder with 175 hp delivering up to 21/29 mpg city/hwy with FWD and 21/27 mpg city/hwy and can seat up to 7 passengers.

NOTE PICTURE IS 2012 MODEL*

Runners Up:

2011 Nissan Rogur FWD 4 dr S
25 MPG combined, $22,595 MSRP

2011 Scion xB dr Wgn Man
25 MPG combined, $16,000 MSRP

2011 Ford Transit Connect XL
Combined 23 MPG, MSRP: $21,200 MSRP

With 135 cubic feet of cargo space, this European-inspired work van has quickly become a big hit for North American commercial businesses, NADAguides reports. The van offers fuel economy of 21 miles per gallon city and 26 miles per gallon highway.

Runner Up:
2011 Honda Odyssey 5dr Touring
23 MPG combined, $40,755 MSRP

2011 Volkswagen Jetta Sportwagen 4 dr DSG TDI
Combined 35 MPG MSRP: $26,095

Fuel mileage for the diesel engine is an estimated 23 mpg city and 33 mpg highway, and offers 140 hp. A less expensive standard engine is also available for the model, with 170hp and 23mpg city and 33 mpg highway.

Runner Up:
2011 Ford Fiesta 4 dr HB SE
32 MPG combined, $15,520 MSRP

2011 Volkswagen Golf 4 dr HB Man TDI
35 MPG combined, $23,885 MSRP

The 2011 Volkswagen Golf is a compact hatchback and is available with two different engines; a 2.5-liter in-line 5-cylinder engine that produces 170 hp and a 2.0-liter TDI® Clean Diesel engine that produces 140 hp. Fuel mileage is estimated at 23 mpg city and 33 mpg highway for the standard engine and 30 mpg city and 41 mpg highway for the diesel variant.

Runners Up:
2011 Audi A3 4 dr S Tronic FrontTrak 2.0 TDI Premium
35 MPG combined, $30,250 MSRP

2011 Volkswagen Jetta Sedan 4 dr Manual TDI LE
35 MPG combined, $22,095 MSRP

2011 Audi A3 4 dr HB S Tronic FrontTrak 2.0 TDI Premium 35 MPG combined, $30,250 MSRP

The A3 comes with a 2.0-liter Turbo-Diesel I4 with 140-hp, 6-speed automatic transmission and up to 30/42 mpg city/hwy.

Runner Up:
2011 BMW 3 Series 4 dr Sdn 335d RWD
29 MPG combined, $44,150 MSRP

2011 Honda CR-Z 3 dr CVT
37 MPG combined, $19,995 MSRP

A completely new sports coupe for 2011, the Honda CR-Z borrows exterior design inspiration from the 1980s Honda CR-X, according to NADAguides. The fuel efficient model is fitted with a continuously variable transmission and gets 37 miles per gallon through average city and highway driving.

Runner Up:
2011 Smart fortwo 2 dr Cpe Pure
37 MPG combined, $12,490 MSRP

2011 Smart Fortwo 2 dr Cabriolet Passion
37 MPG combined, $17,690 MSRP

It may be cozy, but the 2011 Smart Fortwo’s 1.0-liter 3-cylinder engine enables an EPA estimated 33 mpg city and 44 mpg highway. And with a MSRP of $17,690, it is one of the least expensive vehicles on the list.

Runners Up:
2011 Audi A3 4 dr HB S tronic FrontTrak 2.0 TDI Premium Plus
35 MPG combined, $30,250 MSRP

2011 Volkswagen Jetta SportWagen 4 dr DSG TDI
35 MPG combined, $26,095 MSRP

2011 Kia Soul 5 dr Wgn Man
28 MPG combined, $13,300 MSRP

The 2011 Kia shows that fuel efficiency comes in the budget class. The vehicle carries a MSRP of only $13,300, making it the least expensive vehicle on the list. Its 1.6 liter inline-4 engine paired with a 5-speed manual gearbox gets 26 miles per gallon city and 31 miles per gallon highway. In addition, it offers generous cargo volumes with up to 53.4 cubic feet of room when rear seats are folded down, according to NADAguides.

Runner Up:
2011 Mitsubishi Outlander Sport 2WD 4 dr CVT ES
28 MPG combined, $19,495 MSRP

2011 Ford Ranger 2WD Reg Cab 112” XL
24 MPG combined, $18,050 MSRP

Powered by a standard 2.3 liter inline-4 engine on the XL and XLT, this 143 horsepower engine promotes class-topping fuel mileage of 22 miles city or 27 miles highway. A higher-powered 207 horsepower 4-liter V-6 engine is optional on the 2011 Ford Ranger XLT and standard on the Sport trim.

Runner Up:
2011 Toyota Tacoma 2WD Reg I4 MT
23 MPG combined, $16,365 MSRP

2011 Toyota Prius 5 dr HB I
50 MPG combined, $21,650 MSRP

The 2011 Toyota Prius is a mid-size, five-door hybrid hatchback powered by a 1.8-liter 4-cylinder hybrid engine that produces 98 hp and estimated 51 mpg city and 48 mpg highway.