Sonoma County Bicycle Coalition (Sarah Hadler). Interested in bike commuting or just riding your bike more often? Attend our Bike Commuting Workshop with expert League of American Bicycling Certified Instructor Sarah Hadler from the Sonoma County Bicycle Coalition. Sarah is an avid bike commuter and educator who has ridden her bike up and down the coast of California, through Mexico, and all around the streets of Sonoma County. She is a wealth of information about everything bike-related. Come to the clinic to learn and be inspired!