1) Accumulate 2) Amass 3) Collision 4) Freeway nightmare 5) Freeway problem 6) Highway problem 7) Interstate calamity 8) Loose-football aftermath 9) Mess during a commute 10) Multi-vehicle accident 11) Multi-vehicle crash 12) Multicar accident 13) Road accident 14) Road mishap 15) Traffic stopper 16) Traffic tragedy 1) Logjam 
[n] - multiple collisions of vehicles
noun multiple collisions of vehicles