From 24/7 Wall St.: Last year, the average American driver wasted 38 hours sitting in traffic. While the occasional traffic jam inconveniences most drivers, some unlucky people live in the nation’s most congested cities. In addition to spending an average of 42 hours a year in traffic, drivers in these cities face peak hour congestion that can increase travel time during rush hour by 15% or more.
INRIX, a traffic information and services group, collects data for individual road segments. In its 2012 Traffic Scorecard, INRIX calculated the amount of time that congestion added to drivers’ peak hour commute for each road. After aggregating these segments for each metropolitan area, it ranked the Los Angeles area as the city with the worst congestion in 2012. At peak hours, traffic on Interstate 405 in Los Angeles moved at just 14 miles per hour, adding 26 minutes to what should be an eight minute drive. Based on the INRIX Traffic Scorecard, these are the 10 cities with the worst traffic.
According to INRIX, congestion is the difference between the drivers’ actual speed on the road during peak hours and their speed when congestion is not an issue, as distinguished from how fast people are traveling during peak hours. Of course, this problem also extends travel time during both morning and evening rush hours. In 2011, six of the 20 cities with the longest average commute time were among the 10 cities with biggest difference between peak and nonpeak travel time. Two of these metro areas, Washington D.C. and New York, had average commutes of more than 34 minutes — the longest in the nation.
Not surprisingly, population density is a contributing factor to traffic congestion. Of the 10 metro areas that had the highest population density as of 2010, six were also among the nation’s 10 most congested. This group includes New York, Los Angeles and San Francisco, the three most-densely populated metro areas in the United States.
In many of the worst cities for traffic congestion, a relatively high percentage of commuters use public transportation. In 2011, more than 31% of New York area residents took public transportation to get to work, more than double any other metro area. Despite this, New York’s peak hour congestion was among the worst in the nation. While a relatively high percentage of residents in these cities use public transportation, highways, bridges and tunnels remain overwhelmed by the millions of commuters that continue to drive to work.
To determine the 10 cities with the worst traffic, 24/7 Wall St. reviewed figures published by the INRIX Traffic Scorecard for 2012. The scorecard assigns an index score for the 100 largest metropolitan statistical areas, and individual road segments within those areas. Scores are functions of the percentage difference between road segments’ uncongested (or “free flow”) travel time and the calculated travel time on the roads during peak hours (6:00 a.m. to 10:00 a.m. and 3:00 a.m. to 7:00 p.m., Monday through Friday). 24/7 Wall St. also reviewed population density from the 2010 Census, as well as travel time and commuting methods for each metro area from the Census Bureau’s 2011 American Community Survey. All data used were the most recent available.
These are the 10 cities with the worst traffic, according to 24/7 Wall St.: