Somewhere in the historical arc there were large land parcels. Then there were smaller land parcels. Then came housing developments, carefully avoiding/incorporating a river (called a Creek) that might (meaning “could be expected to”) flood. Sometime later came limited access highways.
The newest phase of development incorporates pedestrian corridors along the highways, making slow passage parallel fast travel separated by a few meters in elevation and a stout (but not tall) chain-link fence.
In this case, the “creek” now has a fancy pedestrian bridge crossing—Pioneer model(?) Bailey bridge.