The reasons for a roadside license suspension vary depending on the state or province in which the suspension occurs. The most common reasons are driving under the influence (DUI), driving without proper insurance and accruing too many traffic violations.
DUI infractions are the most common reason for roadside suspensions. If, during the investigative process, a driver is proven to have a blood alcohol content (BAC) above the legal limit, their license will be suspended and they may even be arrested. For most drivers, the BAC legal limit is 0.08, however, commercial drivers in Texas, for example, must have a BAC under 0.04. In states where 21 is the legal drinking age, a driver who is under 21 can have their license suspended for any measurable amount of alcohol in their blood. In some cases, a roadside suspension can last for as little as 24 hours, pending conviction of a DUI offense, at which time suspensions, fines or prison sentences can be added.
Another common violation which results in roadside suspensions is the failure to meet minimum insurance requirements. Each state has minimum levels of required liability insurance and if a driver is convicted of driving without insurance, they face suspensions and fines.
Most states use a point system for traffic violations. For example, in Florida, drivers may incur from 3 to 6 points on their record for infractions ranging from littering to excessive speeding. If 12 points, or more, are incurred within one year, the driver's license will be suspended for 30 days. Similar systems are in place across the U.S.