The main reason I would say no is because I don't trust the government to spend the money properly. Politicians have squandered any ability for people to trust them, as far as I'm concerned. There's all these promises of a better tomorrow, but there will be so much waste, so much corruption, that people would rather not tax themselves.
What this is a vague promise of better transit, but no real plan, no budget with accountability, etc. Also, unless I missed something the tax is forever. How often have we seen taxes meant for one thing to be diverted to another thing?