I have just looked at the timetable for the 14/18 in cornwall as my drive to work takes me along the exact route of said bus from redruth to truro. The bus is timetabled for 36 minutes. If I'm starting work between 0830 and 1000 it takes a minimum of 45 mins to drive to work. Likewise if finishing between 1500 and 1800 it takes a minmum of 45 minutes to get home.
The bus also has to pop off route to go into one of the villages which will easily add 5-10 minutes to the journey.
I see noway is a 36 minute bus time possible from redruth to truro in 36 minutes
Remember there are short bus lanes in Truro which helps a few minutes.