Dublin is the 6th most congested city in Europe according to the TomTom quarterly Congestion Index which identifies congestion hot spots across Europe.

The report, initially covering 31 cities, finds Warsaw to be the most congested city in Europe with a 42% congestion level. Dublin
was found to be the 6th most congested city. On average, journey times in Dublin are 30% longer than when traffic in the city is flowing freely and 70% longer during morning rush hour. This is a significant rise in traffic congestion in Dublin from last year then Dublin was the 24th most congested city with a 24.2% congestion level. The TomTom Congestion Index, including individual city reports, can be found at www.tomtom.com/congestionindex.

The TomTom Congestion Index is the world''s most accurate barometer of congestion in urban areas. The Index is uniquely based on real travel time data captured by vehicles driving the entire road network. TomTom's traffic database contains over five trillion data measurements and is growing by five billion measurements every day. The overall congestion level for all the cities analysed in Europe is 24% - meaning journey times take 24% longer than when traffic is flowing freely.
 
The top ten most congested cities, ranked by overall congestion level, between January and March 2012 were:

1.   Warsaw, 42%
2.   Marseille, 41%
3.   Rome, 34%
4.   Brussels, 34%
5.   Paris, 32%
6.   Dublin, 30%
7.   Bradford - Leeds, 28%
8.   London, 27%
9.   Stockholm, 27%
10.   Hamburg, 27%