SAN DIEGO -- A San Diego attorney claims California driving under the influence laws should not be applied to marijuana usage, 10News reported.

While many have assumed that marijuana affects the ability to safely operate a vehicle, attorney Cole Casey said two federal studies do not support that.

Rudy Reyes has used marijuana for years after 70 percent of his body was burned in the 2003 Cedar fires.

"I constantly have pain," said Reyes.

Reyes said he has gotten behind the wheel with marijuana in his system and has been pulled over dozens of times.

"It had nothing to do with you swerving? Or running a red light?" asked 10News' Charisse Yu.

"The worse one I have yet to have is not having my little cell phone thingy on," said Reyes.

Casey represents people like Reyes, and he said while the California Department of Justice has found that marijuana impairs driving, the U.S. Department of Transportation's studies contradict this.

"There are two federal studies that have come to that conclusion that although marijuana can impact someone's short-term memory, when somebody is concentrating on the task of driving that really there was no measurable impact," said Casey.

Another study by the Department of Transportation showed that researchers found that "it appears not possible to conclude anything about a driver's impairment on the basis of his/her plasma concentration of THC."

Casey said the big problem is that THC, the active ingredient found in marijuana, stays in the body for up to 30 days.

"It's very difficult to pinpoint, 'Yes, somebody has ingested marijuana,' but are they 'impaired,'" said Casey.

While opponents said marijuana damages brain cells and respiratory systems, Reyes said other legal drugs are much worse.

"Marijuana is not where people are having most of their driving problems; most of them are alcohol," said Reyes.

In California, drivers can be arrested for driving under the influence while on any medication -- depending on how much is taken and whether it impairs driving ability.