Step 3: Apply for a permit and pick a date
Here's a cool reason to check with your local alderman to find out whether block party permits are required in your area: Some cities provide free stuff with the permit! For instance, Arnold lives in Chicago, where free block party permits include a complementary Jumpy Jack (those big, balloon-like things kids can jump around inside) and a pinata, as well as a visit from a Chicago Fire Department truck. (These freebies are in addition to "No Parking" signs provided by the city, as well as city-tagged sawhorses to block off the ends of the street from car traffic the day of the event.)
Arnold applied for his block party permit about three months before his party, mainly to ensure the Jumpy Jack and Fire Dept. would be available on the chosen date.
Most alderman in Chicago require that first time applicants gather signatures from their neighbors to show that there's support for the party on the block. The number of signatures required varies from ward to ward. So if you're a first-time applicant, you'll need to gather signatures by going door-to-door. Ask your volunteers to help you with this since it can be daunting to do this alone if you've never knocked on doors before. People who've thrown block parties on their street before usually don't need to gather signatures of support.
Though you can never predict the weather, you may want to take it and other things into consideration when choosing a date. Arnold's block party group chose July because the summer season in Chicago is at its peak, and most families wait to go on vacation until August. You may also want to avoid picking a date that competes with a major local event, like a music festival or church picnic happening in your neighborhood. Your alderman's office will likely make this a requirement.