This achievement comes down to mere luck. You can get it in Wyatt's chapter in the 400 days chapter. If you fail to get it, rewind and try again. it it missable!
When you hit a guy/walker with the car, you will discuss whether or not to look for the guy. Choose we should check together and when your friend proposes to rock paper scissor it, say that that is fair. Other strategies state that Always giving paper works to win (you need to win 2 out of the possible 3 games). My own strategy involved starting with paper, then depending on what your opponent chooses make your next call. The other guy chose paper as well, so I assumed he'd choose scissors to beat my paper (if I were to choose that again), so I went for rock. Turned out that way. I assumed he'd choose paper afterwards to beat my rock (if I were to choose that again), so I chose scissors. Again, it is luck involved but this strategy worked for me.