California 

How to report an unsafe driver using a dashcam video

Reporting AgencyReporting Link
California Highway Patrolhttps://www.chp.ca.gov/notify-chp 
DMV Medical Driver re-evaluation program https://www.dmv.ca.gov/portal/driver-education-and-safety/educational-materials/fast-facts/potentially-unsafe-driver-ffdl-10/ 

If you report via telephone, Please explain to them what happened and ask for an email address for sending a link to the dashcam video.