(MONEY Magazine) – Q What's the difference between all-wheel drive and four-wheel drive? Manufacturers refer to their vehicles as being one or the other, and some magazines use the labels interchangeably. I'm confused.

You're not the only one. Subaru alone offers five all-wheel-drive systems on its vehicles. Assuming you don't want to hear about viscous couplings, I'll skip the mechanics. Basically, four-wheel drive refers to vehicles that let the driver manually lock the front and rear axles to send constant, equal power to all four wheels (almost exclusively pickups and hardier SUVs). It's useful for off-roading but causes excess wear on the system if you use it constantly on pavement. Such true four-wheel drive also offers driver-selectable low-range gearing, likewise for off-road action or towing.

In contrast, all-wheel-drive systems are fully automatic and usually less capable off road. Some, like the one found on the Honda CR-V, operate in two-wheel drive until the wheels lose traction. Then they divert power to the other axle, saving some fuel and wear. Others, including systems from Acura, Audi, BMW, Subaru and Volvo, send a varying ratio of power between front and back wheels and redistribute power when individual wheels lose grip.

For most buyers, there's no need to fret over the differences--automakers know what people expect from each type of vehicle. If you're shopping for a burly pickup or SUV, you'll find a selectable four-wheel-drive system. If you want a car or an SUV for everyday travel, you'll find an all-wheel-drive system designed to maximize on-road traction and performance, not tackle Mount Doom.

Q I'm in the process of shopping for a small SUV for my daughter to take to college. Are there any specific models and attributes I should be looking at?

First consider whether an SUV is the best choice for a young, inexperienced driver. While SUVs tend to perform well in collisions, and offer the traction benefits of all-wheel drive, they just don't handle as well as most cars do during emergency situations, leading to the off-pavement excursions that cause most rollovers. I'd check out mid-size or even larger cars, still the safest vehicles overall. That said, if you're set on an SUV, look for models with safety features like anti-lock brakes, side and side-curtain air bags, and especially stability control, which can reduce the risk of skids, spins and rollovers. For 2005 the Honda CR-V ($20,510) has added standard stability control with rollover sensors, plus side and side-curtain air bags. For less money, you can get the all-new Hyundai Tucson ($18,094). It's less spacious and refined but delivers an impressive roster of standard safety gear.