RICHMOND, Va. (WRIC) — Marijuana will be legal in Virginia on Thursday and the change has American Automobile Association (AAA) concerned about safety on the roads.

Beginning July 1, anyone over 21 will be allowed to possess up to an ounce of marijuana, but the agency says just because it’s legal, doesn’t mean it safe to use behind the wheel.

The agency looked at 10 years worth of data which suggested legalizing recreational marijuana may increase the number of THC positive drivers involved in deadly crashes.

Crash rates and insurance claims also increased in Colorado, Nevada, and Oregon after legalization passed.

Data from the Colorado Division of Criminal Justice found deadly crashes involving cannabis increased up to 153% in other states.

AAA says while marijuana affects people differently, it can impair reaction time, attention and coordination.

They’re urging drivers if they do choose to use, to not get behind the wheel.

Even when legalization takes effect Thursday, Virginia law bans drivers and passengers from smoking or consuming marijuana while a car is being driven.