The Oklahoma Highway Safety Office is warning people about the dangers of driving while under the influence of marijuana. 

Several counties will have extra patrols out on Saturday to watch for people using the drug and driving.

The agency said the drug slows reaction time and affects driver's ability to stay in their lanes. 

"Somebody that takes any kind of prescription medication or even illegal drugs, they're using that to make them feel different and in turn, it's going to make them drive differently," said Trooper Lisa Jorgensen with OHP. 

OHSO said people using the drug should treat it like alcohol, find a safe ride home and keep the keys away from impaired friends.