"The increase in law enforcement officers who are trained in recognizing drug use, from 129 in 2012 to 214 in 2018, can increase drug detection rates apart from any changes in driver behavior.

"Traffic safety data were obtained from a number of different sources. Please note that traffic safety data may be incomplete because law enforcement officers may determine that alcohol is impairing the driver, and therefore additional (time consuming and costly) drug testing may not be pursued.

"The total number of marijuana arrests decreased by 52% between 2012 and 2017, from 12,709 to 6,153. Marijuana possession arrests, which make up the majority of all marijuana arrests, were cut in half (‐54%). Marijuana sales arrests decreased by 17%. Arrests for marijuana production increased appreciably (+51%%). Marijuana arrests that were unspecified, meaning the specific reason for the arrest was not noted by law enforcement, went down by 45%.