Intentional
traffic collisions may be a chosen method of suicide where
speed limits are high enough to produce fatal
deceleration. Modern cars have high rates of acceleration and can easily reach very high speeds in short distances, while most cars cannot protect occupants from
disability or death in frontal impact collisions exceeding . Motor vehicles can be tempting as machines of self-injury or self-destruction for individuals attempting to disguise their suicidal motivation, because widespread use of the word
accident implies traffic collisions are unintentional, and because traffic collisions are already so frequent. The percentage of suicides among the tens of thousands of people killed annually in United States traffic collisions is unknown because suicides are often misclassified as accidents if no suicide note is found. Considering the large number of suicides by other methods, it would be remarkable if vehicles were less used as a convenient method of self-destruction trying to minimize insurance and religious complications. In addition, many attempts at driver suicide presumably result in permanent disabilities rather than death. The probability and severity of traffic collisions may be increased by
suicidal behaviors including
drunk driving and
speeding. These risky driving behaviors are associated with
depression as contributing factors to vehicular suicide. Impact velocity may be maximized by exceeding speed limits or by maneuvering into a
head-on collision with a heavier and less maneuverable vehicle like a
bus or
semi-trailer truck. Crash investigators found head-on collisions with heavier vehicles were a suicide method more common than the single vehicle crashes sometimes assumed to be more typical. These suicidal collisions may kill or injure others. Motor vehicles remain widely available while
gun control reduces access to firearms. The percentage of traffic fatalities which are suicides appears to be increasing with time. Understanding the fraction of traffic fatalities attributable to suicide is important because many
traffic safety measures are unlikely to influence suicides. Unmeasured suicides in
empirical data used to evaluate traffic safety measures will result in systematic underestimation of effectiveness for non-suicidal road users. ==See also==