Tennessee on Monday became the nation’s 22nd state to enact legislation allowing public funds to go to private schools as Gov. Bill Haslam signed into law a measure aimed at special needs students.

The Individualized Education Act, which easily passed in the Tennessee legislature in April, will provide families of about 18,000 students with severe disabilities the option to forego public schooling for a bank account holding public funds for “education-related expenses,” which can include physical therapy, private schooling, home schooling, textbooks and even college courses after graduation from high school.

The measure will take effect in 2016.

Proponents say the voucher program will improve education for disabled students who opt in by providing them with a customized education that is of higher quality than what they receive in public schools. “No one is better suited to understand a child’s distinct learning needs than a parent, and no one can offer better direction in choosing the right educational options for them,” said Daniel Zavala, state policy director for StudentsFirst, an advocacy group founded by former District of Columbia schools Chancellor Michelle Rhee.

Others, including educators and special education experts, are concerned that parents will unwittingly waive rights and protections granted to special education students in public schools under federal law, and also that public schools will lose needed funds as a result of the legislation.

Though the Individualized Education Act stands to have a major impact on Tennessee schools, it was not the voucher legislation that dominated conversation throughout the legislative session. A voucher bill for low-income children, expected by many to pass, stalled for the fifth time.