The U.S. Postal Service hopes to save $3 billion a year through a series of changes reflecting its greater reliance on regional hubs that revise delivery time standards while retaining three-day local mail delivery and offering customers more precise point-to-point delivery estimates. Election mail won't be affected, officials said.

The proposal, announced Thursday, would adjust first-class mail delivery times while maintaining a commitment to a maximum five-day delivery in the U.S. and local mail delivery of three days. It also would allow postal customers look up precise delivery times for mail between specific zip codes, officials said.

Postmaster General Louis DeJoy said the changes are necessary to "enable us to operate more efficiently and reliably, grow our business and give us a chance for a viable future" after an 80% drop in first-class mail since 1997 and a corresponding growth in packages. All told, the Postal Service has amassed more than $87 billion in losses from 2007 through 2020.

Details were unveiled Thursday as the Postal Service announced a Sept. 5 conference in which the proposed changes will be discussed — and possibility modified — before being submitted to the Postal Regulatory Commission.

Election mail and holiday shipments won't be affected because the proposed changes would not take place until the new year, officials said. Medications also should continue to be delivered at their current speed, or faster, under the proposal, officials said.

The proposal reflects the Postal Service's move to larger hubs connecting local post offices, something that is already beginning to take place in Atlanta, Richmond, Virginia, and Portland, Oregon. Changes to better utilize ground networks mean the Postal Service must adjust pickup and drop-off times between post offices and processing plants, officials said.

This proposal aligns with the organization's mandate to be financially self-sufficient while continuing to deliver to every address across the nation six days a week. If adopted, 75% of first-class mail will see no change from the current service standards, and around two-thirds of mail will be delivered in three or or fewer days, the Postal Service said.