Costco store visits have surged, while other major retailers have remained flat. Bloomberg/Getty Images Costco keeps getting busier, with store visits up by more than 18% over the last seven years. Traffic trends at Walmart and Target are mostly flat, according to Placer.ai. The growth brings additional pressure on warehouses, and Costco is having to get creative with fixes. Costco's sprawling sales floor is sometimes likened to a racetrack, but lately it can feel more like a demolition derby. It's a change that has taken a few years to emerge, but new numbers from Placer.ai, a market research firm that analyzes foot traffic, show how much more crowded Costco has gotten in the last few years. Shopping visits to Costco warehouses ticked up by more than 18% from the first quarter of 2019 to 2026 as US consumers have turned to the club for relief from rising prices (and the occasional free sample). That growth has come through a combination of visits to new warehouses and increased traffic at existing ones.…