INRIX, a leading international provider of traffic information and driver services, launched the INRIX Gridlock Index (IGI), a new monthly report that measures the intensity of gridlock in 10 of the largest cities in the US. In October 2012, the aggregate IGI score was 17.6, meaning the average driving trip in these cities took almost 18 percent longer than necessary, due to traffic.

October's traffic congestion data shows that while we are still sharply down from 2010 levels, gridlock has recently been on an upward trend since July 2012. While this may be bad news for the nation's drivers, it may also be a signal that the economy is back on track.

"We believe the IGI is a useful tool, not only for measuring traffic congestion but for also measuring broader economic trends," said Bryan Mistele, CEO of INRIX. "It tells us whether businesses are shipping products, people are going to work and shoppers are going to the mall. What the IGI's telling us now is that we're mired in a stop-and-go economy."

According to October's IGI, traffic congestion in these 10 cities was up only 0.75 percent from the previous month, in sharp contrast to August and September increases of 10.5 percent and 12.4 percent, respectively.  Today's release includes data for October 2012, with monthly comparisons dating back to January 2010.

Additional October 2012 IGI highlights include:

• Fewer jobs, less traffic -- Of the 10 cities measured by the IGI, Detroit drivers experienced the least amount of delay in October (an IGI score of 8.5 ) compared to other IGI cities, and also the highest rate of unemployment (10.8 percent).

• Boston was the only city whose IGI score decreased compared to the previous month (from 17.2 to 16.8). Its unemployment rate also crept up from 5.8 percent in September to 6 percent in October.

• New York's IGI score of 21 for October was just shy of its year-to-date high of 21.3. Only drivers in Los Angeles and San Francisco faced worse delays.

• Washington D.C. benefited from having the lowest unemployment rate among the IGI cities (5.3 percent in October), which may have resulted in commuters experiencing some of the worst delays (an IGI score of 17.7).   

• Despite having the highest increase in gas prices as compared to October 2011 (more than 16 percent higher), Los Angeles drivers experienced the worst delays in the country, with the average trip taking them over 30 percent longer (an IGI score of 31.2) due to gridlock.

• Strong employment driven by the tech sector may have offset higher gas prices in San Francisco and resulted in Bay Area commuters experiencing the second worst traffic in the country, afterLos Angeles (an IGI score of 27). San Francisco's IGI remained unchanged from the prior month and stood at its highest point for the year.