Traffic Congestion Statistics Glossary

The categories in Traffic Congestion Statistics are defined as follows.

 

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Category Definition
Population
Population (000) Combination of U.S. Census Bureau estimates and the Federal Highway Administration's Highway Performance Monitoring System.
Population rank Out of 75 metro areas
Population group Size of meto area. Sml (small), Med (medium), Lr (large), Vlg (very large)
Peak road travelers Travelers who made a trip during the peak periods
Urban area size in square miles Size of area
Freeway
Freeway daily vehicle-miles of travel (000) The average daily traffic of a section of roadway multiplied by the length of that section of roadway
Freeway lane miles Total measure of all lanes
Principal arterial streets daily vehicle-miles of travel (000) The average daily traffic of a section of roadway multiplied by the length of that section of roadway
Principal arterial streets lane-miles Total measure of all lanes
Cost Components, Delay, and Wasted Fuel
Value of time ($/hour) The 2005 value of person time used in the report is $14.60 per hour based on the value of time, rather than the average or prevailing wage rate.
Commercial Vehicle Operating Cost Truck travel time is valued at $77.10 per hour for the purposes of estimating congestion cost.
Fuel Costs Statewide average fuel cost estimates were obtained from daily fuel price data published by the American Automobile Association (AAA).
Total annual delay (1000 person-hours) The value of lost time in passenger vehicles and the increased operating costs of commercial vehicles in congestion
Travel time index Ammount of additional time that is required to make a trip because of congested conditons on the roadways. Includes recurring and incident conditions.
% of Daily Travel During Congested Times 6:00 - 9:30 am and 3:30 - 7:00 pm
Operational Treatments Freeway incident management, freeway ramp metering, arterial street signal coordination, arterial street access management and high-occupancy vehicle lanes.
Public Transportation Regular route service from all public transportation providers in an urban area.
Congested Travel
Congested System
Annual Roadway Deficit (lane-miles) to maintain congestion level The number of lane-miles that an urban area is short of to offset traffic growth.
Excess Fuel Consumed Increased fuel consumption due to travel in congested conditions rather than free-flow conditions.
Congestion Cost Value of travel time delay (estimated at $14.60 per hour of person travel and $77.10 per hour of truck time) and excess fuel consumption (estimated using state average cost per gallon). 2005 values include the effects of operational treatments.
Transit or Carpool Riders needed to maintain congestion level The number of transit trips needed to maintain the same congestion level

 

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