Additional bus companies, listed as existing during additional years or decades, are mentioned in old City Directories, and in the WPA American Guide Series of state guidebooks.
Chieppo Bus Co. - existed in 1940's to 1960's.
Theodore Clark - existed in 1950's to 1960's.
Robert Dunn - existed in 1950's to 1960's.
Orange Street Bus Line - city service in New Haven, existed in 1920's to 1960's.
Elmer Christian Sorenson - existed in 1950's to 1960's.