Contra Costa County Traffic is the courthouse that serves the former Mt. Diablo Judicial District and the communities of Avon, Clayton, Clyde, Concord, Martinez, Pacheco and Pleasant Hill. You can file small claim, traffic, landlord and tenant and domestic violence restraining order cases. Clerks accept payment of traffic fines, fees and sell court forms. There is a drop box on the left side of the courtroom door for payments or correspondence.