here's a link to a post about Seattle's recent road diets at the largest cycling club in the nations' website from David Hiller, Cascade Bicycle Club's advocacy director.
Seattle has improved two dozen significant routes thru road diets and rechannelization. These road diets are proving to:
reduce speeding by a significant extent,
increase pedestrian safety,
increase effective use and safety of roads for bicyclists,
and increase ADT carrying capacity of roads by reducing turn delays from center two lanes of traditional four lane arterial layouts.
link here to the cascade article, cascade its about three articles down and i couldn't link directly to it due to quotes in the tagline.
and a link the a seattle transportation brief on the latest rechannelization project
SDOT statements on Nickerson road diet
despite the effectiveness and lack of negative impact on freight or carrying capacity while at the same time significantly increasing safety for road users and pedestrians, road diets seem to always be met with knee-jerk NIMBYism from local business groups.
some statistics from the latest road diet on Stone Way:
Motor vehicles now traveling at speeds closer to the posted 30 mph limit.
• A decline of more than 80 percent in those going faster than 40 mph.
• The changes made to the street lowered total all collisions by 14 percent and pedestrian collisions by 80 percent.
• Motor vehicle traffic volume decreased 6% on the corridor over the study period. This might lead one to believe that the project increased traffic on adjacent streets as people changed routes to avoid delays, but traffic decreased more on adjacent streets than it did on Stone Way N itself.
• Bike traffic – the stuff we care about – increased 35% over the period and represents 15% of the peak hour volume.
Road diets work to calm streets, increase safety and reduce barriers to effective roadway bicycling.