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The following is from the ITE Trip Generation Manual (6th Edition). I've just applied the "average rates" used in the manual. There are some calculations you can do to get a little more detail, but at the end of the day it's all just a guesstimate anyway.
Library (Land Use Code 590)
Trip Generation per 1000sq. ft. Gross Floor Area.
Average Weekday: 54
Average Saturday: 46.55
Average Saturday Peak Hour: 6.75
Average Sunday: 25.49
Average Sunday Peak Hour: 5.14
Average AM Peak Hour (of adjacent street traffic): 1.06
Average PM Peak Hour (of adjacent street traffic): 7.09
Average AM Peak Hour (of generator (site)): 4.32
Average PM Peak Hour (of generator (site)): 7.02
So...if your library is say 5000sq ft. it would generate 54x5 trips on a Saturday, and so on...
I couldn't find anything on parking. The downtown rate for Toronto is 1 space per 175 square metres. I space for every 10 occupants might be a good rule of thumb rate.