The Colorado state Senate on Thursday approved a bill to expand the number of driver’s license offices that can offer identity documents, including driver’s licenses, to undocumented residents.

The 25-10 vote included a “yes” from one of the Senate’s most conservative members, Sen. Jerry Sonnenberg of Sterling, who was joined by five other members of his caucus in supporting the bill.

Sonnenberg has said he backed the bill because it helps agricultural workers, among others.

The issue of undocumented residents possessing driver’s licenses has divided the Republican caucus. Some caucus members see it as a public safety issue and one that benefits rural agriculture; other caucus members see the measure as part of the debate on illegal immigration.

Last year conservative Republicans on the Joint Budget Committee won approval for what could have slowed the already-troubled program down to a trickle.

The original law, passed in 2013, estimated about 66,000 people would sign up for the appointments. That number is expected to be reached in June, according to the Division of Motor Vehicles in the Department of Revenue. Spending authorization would have reduced the number of available offices down to one once that 66,000 number was reached.

Those who want to access the program have complained that getting the required appointments for those licenses is nearly impossible. Brokers have illegally sold those appointments, sometimes for up to $1,000.

Under Senate Bill 139, however, the program could grow to at least 10 offices around the state, adding locations in Alamosa, Glenwood Springs, Lamar, Montrose, Pueblo and Sterling. The program already operates out of offices in Grand Junction, Colorado Springs and Lakewood, and a fourth office in Aurora that handles renewals only.

The number of offices added would be phased in, with four offices added in the next fiscal year, and the rest added the year after. The program is self-funded through fees charged to those obtaining the licenses, which are good for three years.

During debate on Wednesday, bill sponsor Sen. Dominick Moreno of Commerce City highlighted that the program is cash-funded and would require no taxpayer money.

“We are problem solvers,” he said. “… This is a program that needs fixing. It has not operated efficiently or effectively” since it was started in 2013.

Construction and farm workers on the Eastern Plains often have to make appointments in Grand Junction, which means a full day off work, according to co-sponsor Republican Sen. Don Coram of Montrose.

“It’s a public safety issue,” too, Coram said Wednesday, because a person can’t get motor vehicle insurance without a driver’s license.