Shut Down a Major City Road Bike to Work Day

I love to bike to work.  I've done it off and on in the past and have always loved how quickly the exercise clears my head after a busy day in the office.  I think the city should have one day a year where they close down a major road for miles so people can commute to work by bike.  The benefit of shutting down a major road would be people might actually try biking to work (traffic would be that much worse on the other streets) and find that it is quite nice.