1922 - The Milwaukee Electric Railway & Light Company forms subsidiary Wisconsin Motor Bus Lines to operate buses, and introduces bus service between Milwaukee and Oconomowoc, and between Milwaukee and Janesville. Boulevard Transit Co. introduces bus service between Milwaukee and Madison, shortly after which Wisconsin Motor Bus Lines acquires Boulevard Transit Co.
1926 - Bus service to Madison revised to originate at Watertown, connecting with railway.
1928 - Bus service between Milwaukee and Janesville revised to originate at Waukesha, connecting with railway.
1934 - Wisconsin Motor Bus Lines ceases to be a separate subsidiary of The Milwaukee Electric Railway & Light Company.
1934 - Bus service between Waukesha and Janesville discontinued.