Figure 1: Number of Congested Hours per Weekday: Monthly Average ,,,
Hours per day,,,
,"Chicago
weekday congestion","Houston
weekday congestion","Los Angeles
weekday congestion"
Apr-2004,12.93939,5.70075,7.297623
May-2004,13.604165,5.300922,7.658325
Jun-2004,13.951752,5.340904,7.200759
Jul-2004,14.061394,4.837309,8.099204
Aug-2004,13.100873,5.412273,7.178027
Sep-2004,14.328957,5.904757,8.738095
Oct-2004,13.293647,5.158723,9.119038
Nov-2004,13.133325,5.62083,9.470835
Dec-2004,11.97082,4.460309,8.869047
Jan-2005,13.67083,5.13333,9.016665
Feb-2005,12.561405,5.02082,10.045845
Mar-2005,12.807973,5.909426,10.163034
Apr-2005,13.25,6.230152,8.730161
May-2005,13.55,5.468252,8.908733
Jun-2005,13.54999,5.636363,9.431822
Jul-2005,13.234375,6.05,10.1125
Aug-2005,13.325754,5.855078,8.811591
Sep-2005,13.43334,5.753966,9.154757
Oct-2005,13.726195,6.107152,9.007933
Nov-2005,12.895835,5.687495,9.620835
Dec-2005,12.689827,4.833338,7.69048
Jan-2006,11.697373,5.066665,8.887495
Feb-2006,12.6375,5.325,9.262505
Mar-2006,13.076095,5.122995,10.108695
Apr-2006,12.212495,4.8875,8.395825
May-2006,13.3875,4.848486,7.871209
Jun-2006,13.454545,4.48864,9.25
Jul-2006,12.732457,4.30417,8.729165
Aug-2006,13.541668,4.97826,8.025369
Sep-2006,13.451752,5.849995,9.51667,,
Oct-2006,13.746209,5.946981,9.45075,,
Nov-2006,12.64583,5.80418,9.6875,,
Dec-2006,11.245605,4.879165,8.44999,,
Jan-2007,11.015866,5.37698,8.789685,,
Feb-2007,12.97916,5.812495,9.596489,,
Mar-2007,13.045459,5.79545,9.037877,,
Apr-2007,12.22778,5.801595,7.63889,,
"NOTE: The number of congested hours per day are not directly comparable across different urban areas because data collection coverage on the freeway system in each urban area can vary dramatically.  In this case, the data cover about 65 percent of all freeway lane-miles in Los Angeles, compared to about 22 percent in Chicago where data collection is focused on a smaller, more congested portion of the network.  In addition, Chicago tends to have lower free-flow speeds on its monitored freeway network compared to Los Angeles. ",,,,,
"SOURCE: Calculated from data used in preparation of Federal Highway Administration, Urban Congestion Report, April 2004–April 2007.",,,,,