The Toyota Corolla has long been the best-selling compact sedan in the U.S., and the all-new 2014 Corolla is a considerable advance over the aged, grim, unexciting model it replaced.

We recently tested the most fuel-efficient model, the Corolla Eco, over our usual test route of about two-thirds highway and one-third stop-and-go urban and suburban travel, covering almost 250 miles in total.

Our 2014 Toyota Corolla LE Eco, which is rated at 35 mpg combined (30 mpg city, 42 mpg highway), returned 33.1 miles per gallon for us--or about 5 percent lower than its rating.

MORE: 2014 Toyota Corolla - full review

That's well within the 10-percent margin of error most owners are comfortable with, and the three Corolla Eco owners thus far who've posted their own ratings to the FuelEconomy.gov site have averaged 34.5 mpg.

2014 Toyota Corolla L

2014 Toyota Corolla L

Based on our single early impression and that data, we surmise that the Corolla Eco should consume about 3 gallons of gasoline per 100 miles traveled.

That's half again as much as three different 50-mpg Toyota Prius models (assuming they deliver their rated 50 mpg), but that result at least brings the Corolla into competition for the most fuel-efficient conventional (non-hybrid) compact cars.

2014 Toyota Corolla 4-door Sedan CVT LE (Natl) Rear Seats

2014 Toyota Corolla 4-door Sedan CVT LE (Natl) Rear Seats

There are no fewer than five different gas-mileage ratings across the entire 2014 Corolla range.

The least fuel-efficient is the base model with automatic transmission, fitted with the 1.8-liter engine used in all Corollas and an old four-speed automatic. It's rated at 31 mpg combined (27 mpg city, 36 mpg highway).

Slightly better than that is the true base model, with a six-speed manual gearbox, at the same 31 mpg combined, but 28 mpg city and 37 mpg highway respectively.

Using Toyota's new continuously variable transmission (CVT), as our Eco model did--it's optional on several trim levels--raises mileage to 32 mpg combined (29 mpg city, 38 mpg combined--except 37 mpg in the Corolla S model, which programs the CVT to simulate the behavior of a seven-speed automatic).

MORE: New 2014 Toyota Corolla L Base Model To Start At $17,610

Our handful of quick impressions after three days behind the wheel:

  • The CVT generally behaved well, with less engine roar on hard acceleration than you'd find in a Prius
  • But there was a perceptible lag in takeup when accelerating from rest that we've not observed in other cars with CVTs
  • We found the Corolla to engage abrupt and startling engine braking at highway speeds on steeper downhill sections; it wasn't alarming, but it was definitely noticeable
  • The new Corolla interior, with pale grey dash panels setting off the black dash cover--and even a thin blue accent stripe--is miles ahead of the previous generation, and a far more pleasant place to spend time
  • It did have several horizontal surfaces and ledges that had already gathered dust--as had the tediously predictable glossy piano black panels meant to add class
  • Toyota still had a handful of the old hard-plastic pieces, and we could have done without the fake molded "stitching" along the edge of the dash top
  • The fabric inserts in the door--whose contrasting stitching is real, oddly--are a nice touch and "class up the joint," as a friend said
  • The infotainment is vastly improved, with intuitive audio controls, an easy Bluetooth pairing setup, and well-integrated text messaging with canned responses available

2014 Toyota Corolla L

2014 Toyota Corolla L

Finally, we'd suggest that Toyota has missed a bet by not fitting start-stop as an option to switch off the engine while the car is stopped.

We were reminded of this waiting for a very long freight train to pass a railroad crossing, but it also applies to some of the traffic-light cycles in suburban mall areas, which lasted well over a minute.

Our 2014 Toyota Corolla LE Eco carried a base price of $18,700.

Contrary to our usual experience in media-fleet test cars, it had no options whatsoever, so with the mandatory $810 delivery fee, the bottom-line total came to $19,510.

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