Horizontal license and a vertical license.

When UA art student Melissa Arrillaga returned to Tucson from summer break in California last year, she had freshly turned 21.

She and her friends went out to the bars on Fourth Avenue in early September, just to be turned away at the door by bouncers who told her that her vertical California driver’s license was not an acceptable form of identification to buy alcohol.

Vertical state identification cards and driver’s licenses are issued to people younger than 21 years old.

“It’s a really big inconvenience, especially coming from out of state,” Arrillaga, now 22 years old, said. “You can’t get horizontal license online in California.”

A state law enacted in July bans the use of vertical IDs for buying alcohol 30 days after the ID holder turns 21, even if the date of birth on the ID indicates the holder is old enough.

The law seeks to deter underage people from using someone else’s ID to drink, but the law is in its infancy and has had unintended consequences, said Lee Hill, communications director at the Arizona Department of Liquor.

The law, which Hill said is what the liquor industry wanted, alienates people like Arrillaga, an out-of-state student who had to wait until winter break to go back to California to apply for a horizontal license, and visitors from states who may not otherwise need to switch to horizontal.

It rolled into effect just as the state was gearing up for winter visitors and the Super Bowl, and students from out of state returning from break. “Everything was happening in the state,” Hill said.

“It was horrible in the beginning,” she said. “There was a learning curve for the people of drinking age that didn’t have an acceptable form of ID for drinking.”

Bar owners and door hosts in Tucson say they are turning away a dozen or so people on weekend nights and a handful on weekday nights.

“It is what it is,” said Bill Nugent, owner of the Shanty, at North Fourth Avenue and East Ninth Street. “There’s a learning curve.”

The Shanty’s door host, Jonathan Revies, said a lot of UA students already know, but it’s usually their friends from out of town who are “kind of iffy on what to do,” he said. And then there are those visitors who have no idea about the law and tell him that they are here only for a short time, asking to be let in with a vertical ID.

But as a door host, Revies said he has to do his job. The Shanty has signs alerting patrons of the law, citing the exact statute.

“Technically, it counts for everybody,” he said. “You still have to abide by it.”

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Valid forms of ID for buying alcohol are horizontal driver’s licenses from any U.S. or Canadian state or territory, unexpired passports, resident alien cards and military IDs. Military IDs are permitted to be vertical.

Consular cards, Mexican IDs and border-crossing cards are not acceptable for alcohol purchases.

“Apparently, the process in which a Mexican ID is issued is not as stringent as Canadian or United States IDs,” said Hill, the liquor department communications director.

The penalty for establishments that accept unauthorized IDs is a $500 fine for the first offense, $1,000 for a second and $1,500 for a third, she said.

“We realize that has been the outcome, and it has affected people’s vacations and their social time and the bars, bottom line,” she said. “And that’s never what a law intends to do.”

But other states have the same concerns about public safety, especially regarding underage drinking, she said. Eventually, others will catch on in banning vertical licenses for alcohol purchases.

As for Arizona, she said it’s an ongoing process to educate the public.

“We’re hoping that in a one-year cycle, word will get out,” she said.

Contact reporter Yoohyun Jung at 573-4224 or yjung@tucson.com. On Twitter: @yoohyun_jung.