The Manual of the Motor Transport Corps of 1919 spells out the procedure to used in numbering and marking of American Expedionary Force vehicles. There were numerous errors in the downloaded text, which I have attempted to correct based on the most probable word usage.
I don't seem to have much luch adding attachments, but will give it a try. Note that it's in TXT format; let me know if you cannot translate it to WPD or DOC format and I'll see what I can do about reposting.
Should the attachment not work out, look in Google Books using the <full> option under the title listed above. The material is given in Sections 509 - 513, near the end of the documant.
Wish that more countries had published similar material!
Somtimes you just can't get things right no matter what you do! (Maybe the fact that I've got an testinal flu is a factor here!). Para 513 should read:
"513. IDENTIFYING INSIGNIA.
(a) Trucks composing trains or smaller units of not less than twelve trucks will have stencilled or painted on both sides and the rear, distinctive insignia together with the serial number of such truck within the company or other unit. The design must be of simple pattern, readily discernable at some distance and must be black but on a background of any color, which must be more than eighteen inches square. The same design and the same colored background will be used for vehicles in a company or smaller unit, while the same design, but of different color background, for each company will be used for the vehicles in a train. Motor ambu- lances and passenger cars will also bear such insignia, so far as body construct will permit."