Look up Robert Moses (NYC). Or Georges-Eugène Haussmann (Paris), or Ildefons Cerdá (Barcelona). These are general urban planners not strictly concerned with biking, but single individuals can have incredibly extensive effects on huge populations, that may last for centuries (for better or for worse).

In the US, not a single person, but the General Motors/Mack Truck/Firestone Tires/Standard Oil cabal exerted significant influence on shaping how our cities are built. Literally buying up streetcar companies across the nation to put them out of business, among other tactics.

He wrote the CalTrans Bicycle Guide which later became the national AASHTO Bike Guide. These guides prohibited protected bike lanes and discouraged dedicated bike infrastructure until 2012.

It is not an exaggeration, he set national cycling infrastructure policy in the US that stood for decades.

https://en.wikipedia.org/wiki/John_Forester_(cyclist)#1978_C...