Foot traffic referred to the stream of people walking on foot. These people were called pedestrians.
It was also a term for the inflow of customers into a business.
In 1986, foot traffic across streets was directed by pedestrian crossing signs. Many such signs were in San Francisco during that time. (Star Trek IV: The Voyage Home)
In 2259, an alley on Kiley 279 was chosen as the beam-down site for the landing party of the Enterprise due to being void of foot traffic. (SNW: "Strange New Worlds")
In 2373, Quark expressed his belief that Bajor's impending Federation membership would be good for business at Quark's, as it would lead to more people foot traffic on Deep Space 9. (DS9: "Rapture")