The Washington State Patrol normally stops about 1,000 motorists annually for driving under the influence of marijuana.

According to new data released by the WSP this week, some 745 drivers tested positive for pot in just the last six months. If that average continues, it would mean just under 1,500 drivers nabbed in 2013 -- about a 50 percent increase over 2012.

Of the 745 drivers, 420 (how ironic!) were above the state's legal limit of 5 nanograms of active pot per milliliter of blood.

Bob Calkins, a spokesman for the State Patrol, says that doesn't necessarily mean a larger number of drivers are smoking before driving. He says some of that number could be because officers are focusing more on impaired drivers.

However, over the last half-decade, impaired driver emphasis patrols have been stepped up to record levels, and have stayed there. According to information from the Washington Traffic Safety Commission, these patrols have been ongoing and intensive for years, not just in 2013.

Washington state has been devoting enormous resources to the Target Zero program, which began in 2010. Target Zero is a plan to reduce DUI traffic fatalities to 0 by the year 2030.