After his fourth driving-while-intoxicated conviction in 2016, a San Antonio man tried to overturn his four-year prison sentence by arguing that Texas' legal limit on intoxicated driving discriminates against alcoholics.

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Ralph Alfred Friesenhahn argued that the state's driving limit of 0.08 blood-alcohol concentration ignores the higher tolerances that frequent drinkers have to the effects of liquor, allowing the "protected class of alcoholics" to be prosecuted without having to prove that they had lost control of their mental or physical abilities.

The Austin-based 3rd Court of Appeals wasn't buying it, saying in an opinion issued Friday that state law does not unfairly single out alcoholics because it applies equally to all drivers.

Friesenhahn not only failed to present evidence that alcoholics are a protected class under the Americans With Disabilities Act or other federal law, he also failed to prove that the law treats alcoholics differently than other DWI defendants, said the opinion by Justice Cindy Olson Bourland.

“Instead, he argues that they ‘should’ be treated differently … and thus fails to establish an equal-protection violation,” Bourland wrote.

Friesenhahn was arrested after a single-car rollover accident along a rural Comal County road south of New Braunfels. Blood tests later indicated that he had an alcohol concentration of 0.29 — more than 3½ times the legal limit.

His trial lawyer, Gina Jones of New Braunfels, moved to quash Friesenhahn's indictment, arguing that the legal driving limit discriminated against alcoholics, but state District Judge Jack Robison denied the request.

After Friesenhahn was convicted of felony DWI because of his prior alcohol-related convictions, Jones made the same argument on appeal, leading to Friday’s 3rd Court of Appeals decision upholding Robison’s ruling. Jones has not yet responded to an interview request.

Sammy McCrary, chief of the felony division for the Comal County criminal district attorney’s office, said it is ridiculous and misleading to suggest that the law treats alcoholics differently.

“You’re not being punished for being an alcoholic. It’s the driving that’s the problem,” McCrary said. “It’s making the decision to get into a 3,000-pound vehicle … after drinking.”

Trial records show that Friesenhahn also was convicted for driving while intoxicated in Victoria County in 1985 and Bexar County in 1990 and 1998, McCrary said.

Although Friesenhahn argued for leniency in drunken driving laws, the trend has been moving in the opposite direction.

In 1999, the Texas Legislature lowered the state’s legal driving limit from a blood-alcohol concentration of 0.10 to the current 0.08, a limit eventually adopted by every state, and pressure is on to go even lower.

The National Transportation Safety Board in 2013 recommended that states reduce the legal limit to 0.05, saying the move could cut fatal accidents almost in half, and last month the National Academies of Sciences, Engineering and Medicine made the same suggestion, saying studies found lower accident rates in countries that adopted the lower limit.

Last year, Utah became the first state to cut its limit to 0.05 in a law that takes effect Dec. 30.