(CBS13/CNN) – A recent study is taking a closer look at teens and marijuana use.

The study was published last month in Jama network Open. Researchers analyzed data from the 2017 national youth risk behavior survey. They found that more than 45-percent of teens reported having used marijuana in their lifetime.

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And almost half of the teens who smoke pot reported driving after using it. According to researchers, the teens were either 12-years old or older.

Researchers say the percentage of teens who drove under the influence of marijuana was more than double those who drove after drinking alcohol.

Running red lights. Driving at high speeds. Crossing center lines into the opposite lanes. Getting into accidents — even hitting pedestrians. A study published at the start of 2020 found these were some of the dangerous driving behaviors of regular, heavy users of recreational weed who began using before the age of 16.

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Here’s the catch: users drove this badly even when they were no longer high.

The study published in the journal Drug and Alcohol Dependence, asked chronic, heavy marijuana users to drive in a customized driving simulator.

At the time of driving experience, the marijuana group had not used for at least 12 hours, and based on urine tests were not intoxicated on THC, the main psychoactive compound in recreational marijuana.

Despite having no THC in their system, heavy users consistently performed worse on driving tasks than non-users, making critical, dangerous mistakes.

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The worst drivers? Those who began using regularly before age 16.