noun
traffic hell; traffic congestion
Figurative expression likening severe traffic jams to hell; used in news and everyday speech to describe extremely congested roads.
年末の高速道路は交通地獄だった。
The expressway was traffic hell at the end of the year.
渋滞 is the standard neutral term for traffic congestion, while 交通地獄 is a more dramatic, figurative expression.
Compound of 交通 (traffic) and 地獄 (hell), literally 'traffic hell'.