source: The Republican (Danville, Indiana) - issue of Thursday, March 26, 1959 - page 1, column 6:
In March 1959, in an effort to ease congestion, the Danville Town Council passed an ordinance to change the traffic flow around the courthouse square. What had previously been two-way traffic was changed to one-way traffic, going in a counterclockwise direction (meaning traffic from US 36 would enter the square by going south on the west side (aka Jefferson Street), then going east on the south side of the square (aka Marion Street), and then going north on the east side of the square (aka Washington Street).
An earlier article (March 5, 1959) mentions that they had initially wanted to make the one-way traffic go in a clockwise direction - with traffic from US 36 entering the square by going south on the east side of the square (aka Washington Street), then going west on the south side of the square (aka Marion Street) and then going north on the west side of the square (aka Jefferson Street).
The articles noted that some business owners were against the change, wanting the traffic to remain two-way for fear that they would lose customers. The Hendricks County Sheriff and the Danville police chief were both in favor of the change.