Conversation games beat trivia on long drives
Trivia is great for twenty minutes. Conversation games are great for two hours. Hypotheticals, Get to Know Ya, and How Well Do You Know Me all hand the car a question and then get out of the way — the good part is the argument that follows.
They also work with a partner, a friend, or your parents, which most 'party games' don't.
Competitive options for two people
If you want a scoreboard, pick games with fast rounds so the passenger can hand the phone over: True or False, Myth or Fact, Before or After, and Finish the Lyric all run in ten-question bursts.
Games the driver can play safely
The driver should never hold the phone. Read-aloud formats fix this: the passenger reads the prompt, everybody answers out loud, and the passenger taps the answers. Impressions, Two Truths and a Lie, and Would You Rather are all designed this way.