2010 GMC Acadia Owner's Manual - Page 259

Driving and Operating Medical research shows that alcohol in a person's system can make crash injuries worse, especially injuries to the brain, spinal cord, or heart. This means that when anyone who has been drinking - driver or passenger - is in a crash, that person's chance of being killed or permanently disabled is higher than if the person had not been drinking. 9-3 Braking See Brake System Warning Light on page 5‑19. Braking action involves perception time and reaction time. Deciding to push the brake pedal is perception time. Actually doing it is reaction time. Average reaction time is about three‐fourths of a second. But that is only an average. It might be less with one driver and as long as two or three seconds or more with another. Age, physical condition, alertness, coordination, and eyesight all play a part. So do alcohol, drugs, and frustration. But even in three‐fourths of a second, a vehicle moving at 100 km/h (60 mph) travels 20 m (66 ft). That could be a lot of distance in an emergency, so keeping enough space between the vehicle and others is important. And, of course, actual stopping distances vary greatly with the surface of the road, whether it is pavement or gravel; the condition of the road, whether it is wet, dry, or icy; tire tread; the condition of the brakes; the weight of the vehicle; and the amount of brake force applied. Avoid needless heavy braking. Some people drive in spurts - heavy acceleration followed by heavy braking - rather than keeping pace with traffic. This is a mistake. The brakes might not have time to cool between hard stops. The brakes will wear out much faster with a lot of heavy braking. Keeping pace with the traffic and allowing realistic following distances eliminates a lot of unnecessary braking. That means better braking and longer brake life. Control of a Vehicle The following three systems help to control the vehicle while driving - brakes, steering, and accelerator. At times, as when driving on snow or ice, it is easy to ask more of those control systems than the tires and road can provide. Meaning, you can lose control of the vehicle. See StabiliTrak System on page 9‑30. Adding non‐dealer/non‐retailer accessories can affect vehicle performance. See Accessories and Modifications on page 10‑3.