When an occasion is so popular/awesome that it gets crowded
out with people
so much that cars cannot drive down
the road! Usually a sign
of good times and banging music.
Festivals, Carnivals, & live gigs are usually them main culprits
'Goin up to carnival can you drop me off in Notting
'Get the tube man, its gonna be a ROADBLOCK!'
'Dr. Dre doing a live free set in the ASDA carpark, get down
there early, its gonna be a ROADBLOCK!'