United hopes to avoid a federal mandate by delivering all checked luggage within 25 minutes of a flight's arrival.

United Airlines will work to improve baggage delivery as part of an updated customer-service policy aimed at avoiding federally mandated service requirements.

United, the largest carrier at Denver International Airport, said Wednesday it is striving to deliver all checked luggage within 25 minutes of a flight's arrival. The airline said that is its standard but that it may not achieve the delivery time consistently.

Baggage delivery is "one of the last links in the service chain and can tarnish an otherwise positive experience," United chief executive Glenn Tilton said in a message to employees.

The updated customer-service policy covers 12 areas, and United said it gives customers more information on policies and pledges than the previous version.

It also includes information on the airline's new ground-hold policy outlined in May.

United said it will provide customers with compensation, generally with discount travel certificates, if it has a diversion taxi-out delay on the ground before takeoff longer than four hours or a taxi-in delay on the ground after landing longer than 90 minutes. The airline said it has contingency plans to provide food, water, restroom facilities and access to medical treatment for customers aboard planes.

When customers complain, United said, it will respond within 45 days with an answer, resolution or information about next steps to resolve the problem. That's shorter than the 60 days United had allowed previously.

The policy, known as a "customer commitment," is separate from the airline's contract of carriage, which outlines obligations, terms and conditions behind the purchase of a ticket. The company said it will review the customer commitment every six months.

"When we see areas where we're not meeting our customer commitment, we know those are areas where we need to be more efficient and improve service," United spokeswoman Robin Urbanski said.

United's move comes as airlines draw criticism for their customer service and carriers try to forestall a legislated passenger bill of rights by implementing their own policies that don't have the force of law.

Urbanski said federal law already has a procedure in place for prices, routes and services for air transportation.

JetBlue announced its own customer bill of rights in response to a February meltdown that left passengers stuck on the ground in New York for hours.

"The real question is, Do the carriers walk the talk, so to speak?" said Bob Mann, an aviation consultant in Port Washington, N.Y. "The industry as a whole - they were supposed to solve this problem in the late '90s, and it somehow seems to have escaped them."