There was a fairly extensive exchange on transportation during the City Council meeting on first week of June (scroll down to "Lukes"), which was actually based on questions from the Research Bureau report.
Barring that, you could always look at "Transportation" in the FY14 Worcester Public Schools budget.
If you did, you would find that:
Durham School Services is both the Regular Education and Special Education transportation provider. FY14 is the fourth year of a five year contract with Durham School Services.aka: the vast majority of WPS transportation is already privatized (don't let the fact that the buses say "Worcester Public Schools" fool you; that's contractually required).
You'd also see (as has been covered several times; see, for example, the presentation the joint Education/Finance & Operations committee got on transportation earlier this year) that the only buses the Worcester Public Schools run internally are ones where midday transportation is required (that's slide 22). It is cheaper, when we need a midday route, to run it in house rather than contract it out.
And that's checked frequently.
So, please: by all means, make suggestions at improvements. Just get your facts straight first.