Wrong-way driving (WWD) is the act of driving a motor vehicle against the direction of traffic. It can occur on either one- or two-way roads (in the latter case, arising from driving on the wrong side of the road), as well as in parking lots and parking garages, and may be due to driver inattention or impairment, or because of insufficient or confusing road markings or signage, or a driver from a right-hand traffic country being unaccustomed to driving in a left-hand traffic country, and vice versa. People intentionally drive in the wrong direction because they missed an exit, for thrill-seeking, as a suicide attempt, or as a shortcut.
On a divided highway, especially freeway, WWD is a serious problem because of the high speeds usually involved, since the result is more likely a head-on collision. In the United States, about 355 people are killed each year in crashes caused by drivers headed in the wrong direction on the highway. Given an average of 265 fatal WWD crashes, 1.34 fatalities per WWD fatal crash can be calculated. The significance of these kind of crashes is corroborated when this number is compared to the fatalities per fatal crash rate of 1.10 for all other crash types, which translates to 24 more fatalities per 100 fatal crashes for WWD crashes than for fatal crashes in general. Most drivers who enter a divided highway or ramp in the wrong direction correct themselves by turning around.
Depending on the jurisdiction, WWD is a punishable offense. In New Zealand, WWD is counted as careless driving and can result in up to 5 years imprisonment and/or a fine up to NZ$10,000.