Congestion is a growing concern on the nations
transportation system. Not only does congestion make driving more inconvenient
and unsafe, but it increases transportation costs for many American businesses.
The Texas Transportation Institute (TTI) estimates that in the 68 metropolitan
areas studied in 1997, Americans wasted 6.7 billion gallons of fuel and
4.3 billion hours of time because of delay. The total cost to American
motorists in these areas is about $72 billion annually.
Travel (DVMT) per lane mile has increased on all systems over the past
10 years. While DVMT has grown for both rural and urban highways, it
increased at a faster rate on rural routes. DVMT grew by 3.40 percent
on rural Interstates between 1987 and 1997.
![{short description of image}](cpesg_14.gif) Another way to measure operational performance is to
examine peak-hour travel equal or greater than the 0.80 volume-service flow
(V/SF) threshold. This measures only the severity of peak-hour congestion, not
its extent or duration. More than half of peak-hour Urban Interstate travel
occurs under congested conditions.
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![{short description of image}](cpesg_15.gif) Delay increased on all highways between 1993 and
1997, rising from 8.3 to 9.0 hours per 1000 VMT. While calculated
delay declined on most urban highway systems from 1995 to 1997, the reason for
this is unclear. A longer time period is needed to determine if this is the
beginning of a trend. Daily delay is measured by hours per thousand vehicle
miles traveled, and it primarily occurs in urbanized areas (over 50,000
population).
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