To adventure drivers who do their exploring in off-highway-capable SUVs and pickup trucks, unpaved backcountry roads are what foot trails are to hikers. As with non-motorized forms of backcountry travel, there are things to know that will help you have a safe off-highway experience while, at the same time, enjoying wildlands responsibly. This information will serve you well on any of the routes in my Backcountry Byways series (learn more about Huegel's series at backcountrybyways.com).

KNOW YOUR VEHICLE
Familiarize yourself with your four-wheel-drive system. Is it a full-time, part-time or automatic system? In a full-time, or permanent, 4WD system, all four wheels are continuously engaged as driving wheels; there is no 2WD mode. (A multimode system, however, will include a 2WD mode.) Full-time 4WD uses either a center differential or viscous coupling to allow the front and rear axles to turn independently for typical daily driving. Some systems allow the driver to "lock" the center differential so that, in poor conditions, both axles will turn together for greater traction. Some vehicles, like Toyota's 4Runner, Land Cruiser and FJ Cruiser, can be purchased with driver-engaged locking rear differentials—often called "lockers"—that greatly enhance rear-wheel traction. I wouldn't own a 4WD vehicle without one. In many circumstances, particularly if you must crawl over rocks, ledges and deep ruts, a locking differential will vastly improve your ability to get through. It will deliver full power to both driving wheels and eliminate an "open" differential's tendency to transfer power to the wheel with the least traction.

A part-time 4WD system uses only the rear wheels as driving wheels until the driver engages 4WD. A part-time system must be disengaged from 4WD on pavement to avoid excessive drivetrain stress. An automatic system is designed to sense on its own when 4WD should be engaged. All-wheel-drive (AWD) systems, such as those used in some passenger cars and vans, provide power to all four wheels much as full-time 4WD systems do. Many, though not all, AWD vehicles should be thought of as all-weather vehicles, not all-terrain vehicles.

Does your vehicle have a transfer case with low-range gears? More than any other single feature, a transfer case—which is akin to a second transmission—identifies a vehicle suited to all-terrain travel. It sends power to the front axles as well as to the rear axles, and, acting as an auxiliary transmission, provides a wider range of gear ratios for a wider range of driving conditions. Use high-range 2WD for everyday driving in normal conditions, both on pavement and off. Use high-range 4WD when added traction is helpful or necessary on loose or slick surfaces but conditions are not difficult. Use low-range 4WD in difficult low-speed conditions when maximum traction and power are needed and to keep engine revs high while moving slowly through rough or steep terrain.

Does the vehicle have all-season highway tires or all-terrain tires? Tires take a terrible beating in off-highway conditions, for which the latter are designed.

Find out the location and height of the engine's air intake. This knowledge is important to avoid the devastating consequences of sucking water into the engine through the air intake while fording waterways.

Look at the vehicle's undercarriage. Does it have steel plates—usually called "skid plates"—protecting vital components like the engine oil pan, transmission, transfer case and fuel tank? They are essential to helping you avoid the expensive and inconvenient powertrain damage that obstacles, particularly roadbed rocks, can inflict while traveling primitive roads.

Knowing these things will give you a better sense of what your vehicle's capabilities are. "Sport-utility vehicle" used to mean brawny all-terrain, all-purpose passenger trucks like Toyota's Land Cruiser and 4Runner, the vehicles I use exclusively to research my Backcountry Byways guides. Despite their upscale appointments and matching pricetags, they are built for the rigors of off-highway exploring. But lately, automakers, eager to tap into the motoring public's yen for at least the visage of adventure, have begun to apply the label "sport-utility" to just about anything with wheels that can be given an outdoorsy, active-lifestyle look and all-wheel drive. Don't be fooled. Know what you're driving, and drive within the vehicle's limits as well as your own.