Tax deductions, like credits, could be used by those who take the standard deduction if congress specifies so in the law.
I believe that the existing commuter benefit is implemented through the employer because the payments have to be made directly from the employer to the parking garage, mass transit, etc. I don't belive that the employee gets to touch the money first. This simplifies record keeping and reduces fraud.
I would expect that the bill recently introduced would only apply to those expenses that would be similar. Other than parking expenses, I can't see what expenses could be paid directly from the employer. If you use a bike in conjunction with mass transit, you would already be covered if your employer participates in the current program.
EDIT: I should also add that the expenses are paid with pre-tax income and you should not have to claim anything on you taxes since your reported income is reduced by the amount of the benefit.
So, how many people pay to park their bike? How much do you pay?