When passing another vehicle going in the same direction on a two lane roadway or two lane highway you should pass the other vehicle at a speed of at least 10 MPH faster than the other vehicle is going.
Just do not go above the speed limit when passing the other vehicle but you should be going 10 MPH or above the other vehicles speed you're passing on the two lane highway or roadway.
Then return to your lane as soon as possible or when you can see both the headlights of the vehicle you passed in your rear view mirror.
Always be very cautious when passing another vehicle and never pass a vehicle at the crest of a hill and if you really do not need to pass the vehicle it's best to stay in your lane and stay behind the vehicle because passing vehicles gets you into oncoming traffic which could end in a head on crash that could be a fatal decision.