Folded Dimensions: 4 ¼" X 9 ½" 
Open Dimensions: 24" X 38"
Date Determination: There is no date apparent in this map.  The maps used by British American at this time were virtually the same maps published by the Ontario Government.  So a comparison of the Official Ontario Road Map to the British American map can help determine the date of the B - A map.  It has been determined that errors (the omissions of lettering indicating Highway 18, 19, 20 and 30) in the marked 1930-31 Official Ontario Road Map, also appear in this edition of the B/A map.
In addition, reference is made within the map to the B/A company being 23 years old.  B/A was founded on October 17, 1906 - hence the map date of the map should be 1929 thanks to the math (1906 & 23 years = 1929).  However it is realistic to assume that the 23rd anniversary would run October 1929 through to October 1930.  Further, the Ambassador Bridge was not opened until November of 1929 and the bridge is shown on the map, so the map is more likely created after 1929.
Cover Description: The cover is a light cream color - likely more close to white originally - with only red and black text on the cover - no illustrations.
Date Code: Non-Applicable
Main Legend Side Features:
Opposite Side Features:
Other: Compiled and drawn by D Barclay. A. Hay Chief Draughtsman
Note: Highways are numbered except for 18, 19, 20 and 30. Bridges - Ft. Erie - Peace Bridge (1927), Ambassador at Windsor - Detroit (1929),  2 at Niagara Falls - the Honeymoon Bridge (1898-1938) & Lower Steel Arch Bridge (1897), Geo. S. Henry is Minister of Public Highways, highway completely paved from Windsor to Quebec, newly completed Ferguson Highway to Cochrane (1927 according to one reference in Ontario site, 1930 at another part of same site).  Thank you to fellow collector Willie Frey for his assistance in determing the date of publication of this map. 

I do not have this map in my collection - but fortunately for me, Ken Brown; another member of the Road Map Collectors Association, has been kind enough to provide a scan of his map to me to be included in my web site.
The information above is based on what Ken supplied to me.