About 14 percent of drivers under the influence of pot had a child in their vehicle.

There has been an increase by up to 6 percent in the number of highway crashes in four of the states where the recreational use of marijuana has been legalized, according to a pair of new studies. The new reports do not prove there’s a direct risk caused by the use of marijuana among motorists, but they raise caution flags, especially since there is no easy way to test drivers to be sure if they are, in fact, under the influence of THC, the active ingredient in marijuana, said David Harkey, president of the Insurance Institute for Highway Safety’s Highway Loss Data Institute. “It’s certainly early in the game,” Harkey told NBC News. But, he warned, “We’re seeing a trend in the wrong direction.” There are now 30 states that have legalized the use of marijuana for medical purposes, with Oklahoma the most recent to join the list. Nine states and the District of Columbia now have legalized recreational use. With a Gallup poll showing 64 percent public support, more states are set to follow, including Michigan, where recreational use is on the November ballot.

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