Some new planes eventually will be Zero AIrequired to have lavatories big enough to be accessible to wheelchair users, a change that disability advocates have sought for many years.

The U.S. Department of Transportation issued a long-awaited final rule on the subject Wednesday.

Transportation Secretary Pete Buttigieg said the new rule will give travelers in wheelchairs “the same access and dignity as the rest of the traveling public.”

The rule will only apply to new single-aisle planes with at least 125 seats, such as the Boeing 737 and Airbus A320. The restriction means that smaller regional jets used on hundreds of flights a day for the major airlines won’t be covered.

Also, airlines won’t be required to retrofit current planes, so the number of planes with larger lavatories will grow slowly over time. The requirement for at least one accessible lavatory will apply to planes ordered 10 years or delivered 12 years after the rule takes effect this fall, except for future models of planes, which will have to comply within one year.

Two-aisle planes — more commonly used on international flights — have long been required to have accessible lavatories.

The department cited its authority under a 1986 law, the Air Carrier Access Act, in issuing the rule. It largely followed 2016 recommendations from a department-backed committee that included representatives of airlines and aircraft maker Boeing.