Figure 3-3 Highway Reliability As Measured by the Planning Time Index in 18 Cities: January–December 2007, 2009, 2011, and 2012
| Month | 2007 | 2009 | 2011 | 2012 |
|---|---|---|---|---|
| Jan | 1.52 | 1.53 | 1.54 | 1.47 |
| Feb | 1.59 | 1.46 | 1.55 | 1.45 |
| Mar | 1.52 | 1.40 | 1.44 | 1.42 |
| Apr | 1.48 | 1.40 | 1.43 | 1.44 |
| May | 1.50 | 1.41 | 1.46 | 1.47 |
| Jun | 1.48 | 1.39 | 1.47 | 1.48 |
| Jul | 1.45 | 1.37 | 1.36 | 1.42 |
| Aug | 1.49 | 1.38 | 1.40 | 1.45 |
| Sep | 1.52 | 1.42 | 1.47 | 1.48 |
| Oct | 1.56 | 1.51 | 1.54 | 1.52 |
| Nov | 1.56 | 1.50 | 1.54 | 1.52 |
| Dec | 1.58 | 1.53 | 1.48 | 1.58 |
NOTES: Multicity 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.