The Office of Personnel Management on Tuesday outlined changes to its closings and early-dismissals protocol, building on its policy overhaul after the 2010 “Snowmageddon” traffic jams that clogged roads for hours.

This year’s changes include “delayed arrival” announcements. They will tell federal employees either to remain off the roads until a designated time or instruct them to postpone their usual start times by a certain number of hours. Those guidelines would apply when weather and road conditions are expected to improve enough to open government offices, OPM said.

OPM said it will also urge government agencies to increase the number of employees who can telework when offices are closed.

OPM’s goal is to alert workers to severe-weather closings by 4 a.m. Agency director John Berry makes the final decision, based on a conference call with local, state and federal officials who report on conditions and explain how well their agencies can function.

“Anyone who has a transportation or emergency management function is on that call,” OPM spokesman Thomas Richards said during a media briefing Tuesday.

National Weather Service meteorologist Chris Strong, also at the briefing, said the Washington region is likely to experience “a winter close to normal,” adding that residents should always prepare for the unexpected.

In 2010, Snowmageddon trapped thousands of drivers in traffic for as long as 12 hours as blizzards blanketed roads starting around rush hour. That prompted OPM to overhaul its bad-weather policies, mainly by setting a deadline for early dismissals and asking workers to “shelter in place” if they cannot leave by the designated time.

The federal government’s bad-weather policies have led to confusion in past years, and OPM officials acknowledged Tuesday that the previous “federal offices are closed” alert left many federal employees wondering whether they had to report for work or if the notice was only for the general public.

A new announcement will read: “Federal offices are closed — emergency and telework-ready employees must follow their agency’s policies.”

OPM officials said the new wording, which the agency adopted unofficially last year, encourages workers to consult their respective agencies about what to do.