Question from Les Kristt: "Hello Tom ... Have a question please ... When did they discontinue the slanted parking on Broadway? I am going to guess about 1947 ... I am sure you know or can find the answer ... Thank you ..."

Broadway with diagonal parking, circa 1947, Monticello, New York
Broadway, Monticello, New York, with diagnoal parking, circa 1947.

Answer: You're probably just about exactly right, as the description of the above photo shows (from p. 57 of "Monticello" [2010]) attests: 

"This springtime photo shows Broadway (Route 42) from above the corner Oakley (now Lakewood) Avenue. It may be more recent than the newest automobiles shown because production was curtailed during the war years. Mayor Luis DeHoyos opposed elimination of diagonal parking, but parallel parking on Broadway became mandatory in 1946 when the village sought the state's permission to install parking meters. On the right, in the Bogner Building, is the Sol Strand Barber Shop & Beauty Parlor (later David's Fast Photo); Gottesman's Gifts (now Crown Chicken); Bogner's Meat & Poultry; the Green Door Bar & Grill; and Keller Sign Co. Next is Luzker's Hosier; Trachtenberg's (now Chinatown Kitchen); Joe Hertz's shoe repair; taxi-cab company; and another barber. At the corner is St. Peter's Church (minus its steeple), then the Post Office. (Courtesy of Ralph Cutler.)

'Mayor battles to keep wide parking', The Republican Watchman, June 20, 1946.
Republican Watchman, 6/20/1946