There’s still much work to be done, but Tucson International Airport’s major improvement project is already yielding benefits.

Starting Tuesday, passengers began using a new Transportation Security Administration checkpoint for Concourse B, which handles American, Alaska and Delta flights on the far west end of the ticketing level.

Construction on the airport’s Concourse A security checkpoint is scheduled to be completed in August.

The expanded and relocated checkpoints, part of a $28.3 million terminal optimization project, each have four lanes followed by a “recomposure area” overlooking the airfield.

The TSA is expected to bring in additional equipment to staff the extra lane, the airport said.