When is a Ford Focus not a Ford Focus?

— -- The Ford Focus is a terrific car. But anyone who's driven one knows that while it may be economical, reliable and peppy, there is one thing that it is not: intermediate sized. Even if Enterprise Rent-A-Car calls it that.

That's just one example of the confusion consumers face when trying to find the right car to rent. Unfortunately, the rental industry continues to struggle with product standardization so you're often left scratching your head when comparison shopping from site to site and weighing one firm against another. To make matters even stickier, with a few exceptions it's virtually impossible to secure a specific make and model at most rental companies.

Class warfare

On its website, Enterprise defines the intermediate class as "Chevy Cobalt, Ford Focus, or similar" and provides this description: "Larger than an economy and compact car rental, our standard cars [sic] balance the space and budget to give you a great deal on your car rental."

The problem is that Budget and Hertz—which both feature Ford vehicles—list the Focus as a compact, one step below intermediate or midsize. Similarly, the Cobalt is called a compact by Alamo, Avis, and National.

But it doesn't stop there. Enterprise defines the standard class as Pontiac G6 and Ford Fusion, but the G6 is an intermediate or midsize at Alamo, Avis, Budget, and National (Budget agrees with Enterprise that the Fusion is a standard, however). Such confusion reigns at many rental companies, both here and abroad. At Dollar Rent A Car, for example, a Chrysler Sebring is an "intermediate" but a Sebring convertible is a "standard convertible."

Nomenclature is also tricky with rental cars. The terms "intermediate" and "midsize" generally are used interchangeably. You might also be confused by Avis' use of the term "sub-compact" for what the other major domestic rental firms call an "economy" vehicle. And both Dollar and Thrifty have no "standard" class, even though their six largest rivals do.

Travelers probably shouldn't expect relief on this anytime soon. Enterprise spokeswoman Laura Bryant notes that "I don't know of any effort to ensure that all car rental companies are 100% consistent on this issue...we're a pretty competitive and fractious group, as you know."

Seeking benchmarks

In many ways, it would seem renting a car should be the easiest component in the very confusing universe of booking one's own travel. But anyone who has comparison shopped undoubtedly has grappled with the loose terminology used to describe rental vehicles.

Even the leading travel mega-sites don't always speak the same language. For example, Expedia uses the following classifications:

Economy Compact Midsize Standard Full-size Premium Luxury Convertible Minivan SUV Sports car

If you substitute "van" for minivan, and "specialty" for sports car, Orbitz uses basically the same system.

Travelocity, however, offers a total of 30 vehicle classes in all, broken down into four subdivisions: cars; SUVs & trucks; vans & wagons; and specialty. Within the car class, the site substitutes "intermediate" for midsize and also offers the additional class of "mini" below economy, but this is designed for foreign rentals, not domestic bookings.