You and your group of friends were kind of like a biker gang except it was just for riding and for fun

enjoying the empty road that you and your friends have all to yourselves eventually you get to a town and stop for gas.

you go to the bathroom for a while but come out to see you've been left.. their bikes are gone.. You decide to get back onto the road and look for them. you feel your being followed though and can see what looks like a military truck in the distance always following you..