Baked deep into this new Volvo is an extensive array of safety measures that go beyond two-stage front-impact airbags, side-impact airbags, and special head restraints. Notably, Volvo employs several strategies to tackle the rollover gremlin associated with high-center-of-gravity sport/utility vehicles. The first defense is an electronic system that senses roll speed and angle. If these exceed predetermined limits, engine power is reduced and braking one or more wheels is initiated to stay ahead of the roll and regain stability. The second level of defense is special high-strength boron steel in the crush-resistant roof. A third strategy is seatbelt pretensioners to keep passengers securely in place. Finally, an inflatable curtain prevents passenger heads from striking the side glass.
The XC90 is a workhorse that seats as many as seven or can carry more than 90 cu ft of cargo. That adds considerable mass to what is already a pretty stout vehicle. So at all four corners are vented disc brakes at least 12 in. in diameter backed up by a four-wheel anti-lock system. In addition, Emergency Brake Assistance senses a panic stop and automatically applies full braking pressure for a shorter stop.
Even after this rollover test, which we witnessed, all five access doors opened easily. In
Volvo acknowledges that the XC is not intended for extreme off-roading. For that, something like GM's H2 Hummer is a better answer. We were impressed, however, with the XC's off-road moves. The electronically controlled all-wheel drive, developed with Sweden's four-wheeling experts at Haldex, and the 8.6 (2.5T) to 9.2 (T6) in. of ground clearance provide sure-footedness without the belly scrape and clatter of pretend SUVs on moon-crater roads. In normal driving, about 95 percent of the power flows through the front wheels. But if the fronts begin to slip, in as little as one-seventh of a rotation, power can be diverted to the rear contact patches.
Passive safety was a prime XC90 design goal. Its passenger cell is designed to maintain it
The AWD is made up of three main parts: a hydraulic pump actuated by differences in speed between the front and rear axles, a wet multidisc clutch, and a control valve with feedback electronics. When both front and rear axles are rotating at the same speed, no pumping takes place. But if a speed differential occurs, the axles are progressively locked together, smoothly reducing the difference. This all-wheeling setup also interacts with the vehicle's electronic traction and stability control systems to maximize thrust, control, and safety by braking a wheel that tries to spin.