 The regional transit agency , renamed to Sound Transit the following year , began operating its Sound Transit Express buses under contract with Community Transit in September 1999 . The new express buses connected park and rides in southwestern Snohomish County , the only part of Community Transit 's service area within the Sound Transit taxing district , to Downtown Seattle , including the newly opened , 1 @,@ 000 @-@ stall Ash Way Park & Ride in northern Lynnwood . Sound Transit funded several capital projects to improve bus service on the Interstate 5 corridor , including direct access ramps from HOV lanes to Lynnwood and Ash Way park and rides that opened in 2004 and 2005 , respectively . In 2011 , the existing Mountlake Terrace park and ride was expanded with an 890 @-@ stall parking garage and bus platforms in the median of I @-@ 5 connected by a pedestrian bridge . 
