The 20 North American Cities With The Worst Traffic

Every quarter, car navigation system maker TomTom releases the results of its Congestion Index, a breakdown of traffic in North American cities.

The results for Q2 of 2012 (April — June), compiled from GPS readings, may not be shocking (New York, LA, and Houston all make the list), but looking at the 20 cities in North America with the worst traffic, there are a few surprises.

The congestion figure, expressed as a percentage, represents the increase in overall driving times when compared to a "free flow situation"— when there is little traffic, such as at night.

#20 Baltimore

Congestion: 15% increase in driving time over no traffic

Morning peak: 26% increase

Evening peak: 40% increase

Congestion figures from the TomTom report are found by comparing travel times (from TomTom's database of anonymous speed measurements) during peak hours with times while driving in no traffic.

#19 Boston

Congestion: 16% increase in driving time over no traffic

Morning peak: 28% increase

Evening peak: 35% increase

Congestion figures from the TomTom report are found by comparing travel times (from TomTom's database of anonymous speed measurements) during peak hours with times while driving in no traffic.

#18 Dallas-Fort Worth

Congestion: 16% increase in driving time over no traffic

Morning peak: 32% increase

Evening peak: 41% increase

Congestion figures from the TomTom report are found by comparing travel times (from TomTom's database of anonymous speed measurements) during peak hours with times while driving in no traffic.

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