Zero logic

I would have stayed for 4 hours! But the waitress said: "You better leave." So this is one of the more logical script moments. One of the very, very few.
Jeeperscreepers, how can a director choose for the Next Victim an actress who looks exactly like the missing and murdered Leslie? What is needed in that final scene is a red haired lady dwarf!

Re: "why wouldn't you just outrun the tow truck? You're in a Mustang with 400+ horse power."

He obviously had a beefed-up truck.

Re: "why wouldn't you just STOP going the same direction as him and just TURN AROUND AND GO HOME!?!?"

This is a legitimate point and the same thought struck me while watching, but here are some things to keep in mind:

The film was shot in the remote Great Northwest between the Cascades and the Rockies (although it takes place in Washington, it was shot in BC). The roads aren't as numerous as they are in the East and therefore options are fewer. The wild child, Leslie, didn't strike me as someone who would "back down." Also, the trucker seemed pretty adamant about harassing and killing the girls by that point, so even if they went the opposite direction he'd figure it out and come after them. And, besides, who says they didn't turn around at some point? While the movie doesn't show this, it could've happened in between scenes.

Re: "WHY follow right after him when he willingly LEAVES the restaurant you're at and you literally follow him? You can't just hang out for 45 minutes?"

The waitress asked them to leave due to the blonde making trouble. True, they coulda/shoulda just gone the opposite direction as the trucker, yet -- even if they did -- I'm pretty sure he would've figured it out before too long and got back on their tail.