I couldn't talk to you specifically about the tax credit for public transit. However, regarding all tax measures—especially those for students, but also for higher education stakeholders—we have noted the following in our study. Students with an income or students who get in debt year after year to go to school could very rarely use that tax credit. You are talking about public transit, but those measures in no way help increase accessibility to services—whatever those services may be—when students cannot benefit from them or see their concrete effects over the course of the same year.
On November 6th, 2013. See this statement in context.