[231] The information about Maryland’s signs is taken from articles by Harry D. Williar, Jr., Assistant Chief Engineer of the Maryland State Highway Road Commission, in Public Roads, August, 1921, and Engineering and Contracting, October 5, 1921.

[232] “The ‘Wisconsin Idea,’ as Applied to Detours a Source of Satisfaction to Motorists,” by N. M. Isabella, Assistant Maintenance Engineer, in Concrete Highway Magazine, April, 1922.

[233] An article entitled “Prevent the Proposed Permanent Traffic Towers on Fifth Avenue,” by Wm. P. Eno.

[234] “Electric Lighting,” by O. J. Ferguson; McGraw-Hill Book Company, New York.

[235] “Improved Lighting System to be Installed on the Lincoln Highway,” by H. H. Bell, Electrical World, April 15, 1922.

[236] “The Motor Camping Book,” G. P. Putnam’s Sons, New York.

[237] “A Jitney Guide to the Santa Fé Trail,” by Nina Wilcox Putnam, in Saturday Evening Post, June 10, 1922.

[238] Interview with Frank A. Harrison in Nebraska State Journal, July 12, 1921.

INDEX