TomTom Study Reveals Most Polluting Roads in the United States

California roads have long been considered some of the most scenic, and congested, in the United States. A new study by location and navigation solutions leader TomTom gives them another distinction: the nation’s most polluting.

The TomTom study shows the segments of roads on which vehicles produce the most carbon emissions, based on the length and time of average weekday traffic jams and the estimated number of vehicles in those jams. Of the top 10 most polluting major or interstate roads in the country, seven are in California, including: I-5 South (1); I 10 East (2); I 405 South (3); 60 East (4); I 5 North (6); 101 South (8); and I 210 East (9). /p>

The results were calculated using data from Speed Profiles, the historical speed database from the company's licensing business unit Tele Atlas that helps personal and professional fleet drivers find the best routes. Speed Profiles aggregates, anonymously and on an opt-in basis, the actual speeds that millions of GPS-enabled drivers have traveled over the last two years, providing the most accurate view of historical traffic on both primary and secondary roads. It is incorporated on TomTom GPS devices as IQ Routes to guide drivers away from congestion, not only on major highways but on all routes in the road network.

Calculations for emissions were for weekdays, or 300 days of the year. Traffic jams were defined as such if drivers could travel at only 70 percent or less of the posted speed limit, meaning on average an hour-long trip included 20 minutes or more of significant delays.

Key findings are:

  • There are on average 120,000 cars stuck in traffic jams every day on the 170-mile section of California roads in the study.
  • Of the top 10 most polluted stretches of roads in the nation, only three are outside California. They are: I 95 South in Virginia (5); I 93 North in Massachusetts (7); and I 95 North in Connecticut (10).
  • Collectively, the 10 most polluted road segments in the study produce 85,000 tons, or 170 million pounds, of carbon emissions every year. According to the carbon calculator from TerraPass, that’s the equivalent carbon footprint of one person taking 116,000 round trip flights from Boston to Los Angeles. To negate the effects, you would have to plant nearly 100,000 square miles of artificial forest on land the size of the state of Colorado.

The top 10 most polluted major roads also have an impact on drivers’ wallets. Cars sitting in congestion don’t just idle but stop and start for extended periods, burning an additional 0.1 gallons of fuel per hour. At $3 per gallon, drivers sitting on these roads spend $30 million every year on wasted fuel.

Although they have fewer lanes, secondary or non interstate roads can be equally pollution-producing. The top 10 most polluted local roads are:

  • California 1 from Malibu to Redondo Beach;
  • Virginia 7, from Washington D.C. toward Leesburg;
  • Pennsylvania 611;
  • Illinois 64;
  • Georgia 120, from Marietta heading West;
  • New York 25 between East River and Forest Hills;
  • New York 25 A from La Guardia Airport heading East;
  • New York 25 from Jericho to South Huntington;
  • Virginia 7, through Leesburg; and
  • Oregon 99 West, near Portland.

TomTom N.V. provides location and navigation solutions. Headquartered in the Netherlands, it has more than 3,000 employees worldwide.

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