The Book of Rites stated

On The Right Side of the Road
...
...
Lay traced the first regulation of one-side-or-the-other to the
Chinese bureaucracy of 1100 B.C. The Book of Rites stated: "The right
side of the road is for men, the left side for women and the center
for carriages." This Western Zhou dynasty rule applied only to the
dynasty's wide official roads and was "more concerned with protocol
than avoiding head-on collisions." Over 3,000 years later, Lay
concluded, "there are no technical reasons for preferring driving on
either the left or the right side of the road."

https://highways.dot.gov/highway-history/general-highway-history/right-side-road