FIGURE 5-5 Highway Reliability As Measured by the Planning Time Index in 18 Cities: January-December 2007, 2009, 2011, and 2012
NOTES: Multi-city average is weighted by VMT in these respective cities: Boston, MA; Chicago, IL; Detroit, MI; Houston, TX; Los Angeles, CA; Minneapolis-St. Paul, MN; Oklahoma City, OK; Orange County, CA; Philadelphia, PA; Pittsburgh, PA; Portland, OR; Providence, RI; Riverside-San Bernardino, CA; Sacramento, CA; St. Louis, MO; Salt Lake City, UT; San Diego, CA; San Francisco, CA; and Tampa, FL. Planning Time Index-the ratio of travel time or the worst day of the month compared to the time required to make the same trip at free-flow speeds. A value of 1.8, for example, indicates a 20-minute free-flow trip requires 36 minutes during the worst peak period.
SOURCE: U.S. Department of Transportation, Federal Highway Administration, Urban Congestion Report, January 2013-March 2013 (FY 2013, Q2), available at http://www.ops.fhwa.dot.gov/perf_measurement/ucr/reports/fy2013_q2.htm as of November 2013.