I agree that contractors, plumbers etc are pretty bad as they drive from job to job. School bus drivers aren't bad, traffic before and after school hours are dangerous because of rushing parents and new teenage drivers. Pizza delivery drivers can be scary. The problem with large trucks is that often they are unaware of bicycles. In the Boston area there have been at least two fatal accidents involving trucks and cyclists where the truck just kept going. I believe one truck was a garbage truck that killed a brillant young scientist.