The weekday patterns are not always mirrored in the morning
and afternoon periods. The two time periods do not always
have the same degree of congestion for each month, possibly
confounding the monthly weekday congestion estimates
Morning (a.m.) congestion:
• The lowest average morning congestion for all three
cities is in December
Weekday morning congestion is worst in Los Angeles
in March, and in Chicago and Houston in September.
Afternoon (p.m.) congestion:
• Both Chicago and Houston have the lowest afternoon
congestion in January, while May is the lowest for
Los Angeles.
• Los Angeles’ afternoon congestion is worst in February
and March, Chicago’s is worst in September, and
Houston is worst in July and November.