Be on the look out on Thursday, drivers (well, more than you already should) — it's S.F.'s 4th Annual Bike to School Day, in which hundreds of kids and their families take to the streets and ride to school. The event is part of the San Francisco Safe Routes to School Program and is coordinated by the San Francisco Bicycle Coalition. Take a look at the event's website, which has quite a '90s vibe going for it. (CSS not tables, folks. Don't they follow the gospel of the SEO Rapper? [video])

This year's event poster contest was themed, "When I bike I feel _____," which inspired some great entries.

As S.F. Bike Coalition reports, over 2,000 students at 40 schools participated last year. The organizers are encouraging schools and families to organize bike trains, which are groups of people who bike together on a pre-planned route with meet-up points along the way.

Planning on participating? Be sure to check out the S.F. Bike Coalition's handy Family Biking Guide.