4 saucers follow cars then hover above Yuba River in Nevada City. Flashing circle of lights that hum under craft.

Traveling along Yuba River toward N. San Juan,when encounter with 4 golden-year bright saucers (humming sound when close up): younger daughter said, "Daddy, why is the moon following us?"  I said, "Just reflections on window."  
Older daughter replies, "No, daddy there are now 2 moons following us."  I look in the rear view window and see 4 oval lights following the car.  
Up ahead a man is standing outside his car which is pulled over before crossing the Yuba river bridge looking upward above us.  
I pull over, get out of car and see 4 yellow-gold bright shining saucers hovering above Yuba Bridge.  I cross the street and stand under a saucer. Above me is rotating circle within saucer like circling flasing lights with a Vrrrr Vrrr humming sound.  
The saucers hover about then shoot of within seconds East and out of sight.  
Reportings in paper of other witnesses.
Witness indicates that the date of the incident is approximate.  PD