San Francisco International airport overhauled its gate numbering system for the first time in 25 years, implementing a new alphanumeric system that it hopes will simplify the passenger experience as travelers walk through the airport.

San Francisco International airport overhauled its gate numbering system for the first time in 25 years, implementing a new alphanumeric system that it hopes will simplify the passenger experience as travelers walk through the airport.

The change at one of the West Coast’s busiest airports cost $8.9 million to implement and took place overnight from 15 October to 16 October. The gates, which previously had a continuous numbering system from 1 to 102, switched to a system with a letter corresponding to the boarding area (A through G), and a sequential number relative to its location from the checkpoint to the end of the concourse.

“All the wayfinding signage inside the terminals had actually been changed some time ago, but covered with decals noting the old gate numbers until the transition date,” San Francisco airport spokesman Doug Yakel says. “So, all we had to do overnight was pull of the temporary signs to reveal the new permanent signs underneath.”

Passengers who, for example, left the airport earlier in the week from gate 60 in Terminal 3 and arrive back at the same gate will see it now renamed “E4”. Posters placed throughout the terminals show the corresponding gate numbers, and volunteers are on hand to guide confused travelers, the airport says.

More complicated than the interior signage, says Yakel, was switching over the exterior indicators which pilots use to navigate to the correct gate.

“We had to integrate how the airline systems talk to the airport systems, so there were technical systems that required some troubleshooting,” Yakel says. An emergency operations center was set up to monitor that switch overnight. “There were a few hiccups getting some of the airline systems to work.”

The only outstanding task is the repainting of the gate numbers on the tarmac, he adds.

“A lot of US and international airports use this alphanumeric system, and we’ve been wanting to make the transition for some time,” says Yakel. The impetus for the change was the opening of the new Harvey Milk terminal 1, which when fully completed in 2022 will add 25 new gates to the system. The first nine gates in the new terminal, which opened in July, had already been designated according to the new scheme.