A driver who has been drinking is more likely to

A driver under the influence of alcohol is more likely to drive too fast or too slowly, change lanes frequently, and fail to dim the headlights. Even more crucially, a drunk driver may be less alert in an emergency and may take too long to brake. Such mistakes may endanger the driver and others. [How Drinking Impairs Your Driving, Alcohol and Other Drugs, Part 3: Keeping Fit to Drive, State of Maine Motorist Handbook and Study Guide]