The number of casualties caused by drug use in traffic is unknown. A 2011 estimate indicated that blood testing showed one in ten seriously injured drivers to have used drugs. Half of them had also used alcohol. These figures are based on the European DRUID study and date back to 2007-2009 . In comparison: the same study showed that 25% of the seriously injured drivers in the Netherlands had tested positive for alcohol. No information about drug use in traffic by other road users, such as cyclists and moped riders, is available.
In 2012, data sourced by the European DRUID study resulted in an estimate of 5 to 10% of the road deaths being attributable to the use of impairing medicines by drivers . No information about medicine use in traffic by other road users, such as cyclists and moped riders, is available.