Just a quick copy and paste, not quite done with the full edit for Chapter 5 yet.
"Proceed forward to the front of the Semi ahead of you. Have Amy scan the Push symbol on the drivers side door. Timing is critical here, shoot the car to the far left, alerting the two Zombies in the middle of the road. Immediately after, shoot the car directly behind you, removing the Zombie watching the intersection. Sneak around to the left and hide behind the barrier. Then have Amy shoot the car to your right, moving the Zombies in the middle of the road back to where they were. Use this moment to then sneak ahead to the alleyway."
Let me know if you need more help.