Currently there’s only one way in/out of the Arch grounds — via Walnut Street over I-44 (formerly I-70). While the new lid at the center is being completed, everyone is routed via the new bridge over the interstate, on the North side of Walnut Street. However, at some point, St. Louis removed the sidewalk on the North side of Walnut St, between Memorial (3rd St) and 4th.
Looking at the 1997 National Register nomination of the American Zinc building, the sidewalk was in place. Most likely the sidewalk was removed when Drury Inn combined it with two other buildings, see Drury steps up plans for hotel at Fur Exchange site.
Looking at GEO St. Louis it appears this remains part of the public right-of-way (PROW), not vacated to private interests. The PROW was reallocated to give pedestrian space to automobiles. At the time the Cardinals played in Busch Stadium II and Walnut Street was a major point of vehicular egress after games.
I think we need to examine the Walnut PROW to see if the amount for vehicle travel can be reduced by one lane so that a sidewalk can be replaced. Remember, hundreds of millions of dollars are being spent to connect the Arch ground to downtown. The lack of a sidewalk connecting to the South highway crossing point is a huge disconnect.
People know the shortest distance between two points is a straight line.
— Steve Patterson