If you want to make an impact on transportation policy in New York (and you’re a registered Democrat), tomorrow is your big day. All-important seats in the State Senate and Assembly will, for all intents and purposes, be decided in the primary. And if experience is any guide, the margin of victory will come down to a handful of votes in some contests. We’ll have more on that later today, but we can’t stress the importance of your vote too much.

Also this week, community boards are back in action after the summer recess, and Friday marks the return of Park(ing) Day to a curbside space near you.

• Monday: A Manhattan CB 6 committee will turn its attention to the traffic impacts of the Union Square redesign and hear a presentation from NYC DOT about plans to give buses priority on the Queensboro Bridge. 7:00 p.m.
• Tuesday: Primary day — VOTE! Also, the Manhattan CB 2 transportation committee will hear from Council Member Jessica Lappin’s staff about her bill, Intro 121, to regulate commercial cyclists and the businesses that employ them. 6:30 p.m.
• Wednesday: What can be done to calm traffic on Canal Street, Varick Street, and Sixth Avenue? A Manhattan CB 1 committee will discuss. 5:30 p.m. Also Wednesday: Manhattan CB 3 is looking for input on the design of Forsyth Plaza, and will consider asking DOT to allow school buses to load and unload in bike lanes. 6:30 p.m.
• Thursday: Second Avenue Sagas blogger Ben Kabak, Naked City author Sharon Zukin, and transportation analyst Charles Komanoff will share the stage for a forum called “Geeking Out: The Anatomy of the Big Apple” at JLA Studios in DUMBO. 7:30 p.m.
• Friday: Park(ing) Day 2010! 50 curbside parking spaces throughout the five boroughs will be reclaimed as public space all day long. See the map of all the parking spot squats right here.