Legal Question in Traffic Law in California

Legally, the answer is no. It is considered a trespass. Realistically, it might be difficult to enforce, unless you chain or gate your driveway. You might attempt to diplomatically address this with the officer and/or his superiors, especially if you need to exit and enter the driveway during the day because someone at home has a health problems and might need emergency care on a moment's notice. The benefit you receive is that the officer's presence is slowing down vehicles on your road, which keeps it safer than if the officer were not there.