Traffic Lab is a Seattle Times project that digs into the region’s transportation issues to explore the policies and politics that determine how we get around and how billions of dollars in public money are spent. If the best things in life are free, then parking at some of the most popular light rail stations in the Seattle area will soon be less than best. Make that far from best, according to several commuters on a recent morning. Sound Transit, which runs the 58-mile train system , is inaugurating a new paid parking program, starting Friday at three stations: Northgate and the two in Shoreline. Most spots will remain free and first-come, first-served. But upward of a quarter of spaces will be reservable, for $60 a month or $6 a day, for those who want a spot but don’t want to show up while most people are still hitting the snooze button. Permits will be needed only from 4 to 10 a.m. on weekdays, and only in permit parking zones. The spots will revert to being free for all after 10 a.m.…