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Archive – Urban Mobility Reports: 1999-2005

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2005 Urban Mobility Report

What's New

Each year the Urban Mobility Report revises procedures and improves the processes and data used in the estimates. In doing so, the report also revises all previous estimates so that true trends can be developed whenever possible. Some key changes for this year are:

  • Four urban areas moved into a new population group in 2003. All historical statistics were updated with these changes. Atlanta and Phoenix were moved into the "Very Large" group. Providence was moved into the "Large" group. Allentown-Bethlehem was moved into the "Medium" group.
  • The researchers have refined the numerous equations and calculations used to produce the Urban Mobility Report. Minor changes to the computer programs have been made and the historical trend data reflect the new information and procedures. Additional changes are anticipated at the conclusion of the study.
  • The calculation methodology has been changed to provide an improved estimate of fuel wasted during congested conditions. The new values show the amount of wasted fuel as approximately half of the previous total. The year-to-year trend is the same—increasing fuel consumption and fuel costs.
  • The operational treatment effects are included for 2000, 2001, 2002 and 2003 mobility estimates. The data provide a better picture of the travel conditions in those four years. Unfortunately, the long-term trend analysis for years before 2000, does not yet include this information.

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2005 Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader
The 2005 Urban Mobility Report - with Appendix PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader
Methodology for 2005 Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

The 2004 Urban Mobility Report

What's New?

Each year the Urban Mobility Report revises procedures and improves the processes and data used in the estimates. In doing so, the report also revises all previous estimates so that true trends can be developed whenever possible. Some key changes for this year are:

  • An increase from 75 to 85 areas studied. The new urban areas mean that all urbanized areas in the U.S. with a population greater than 500,000 and all of the top 70 urbanized population areas are included in the report database.
  • Five urbanized areas in the 2003 report were combined into two areas for the 2004 report. The US Census Bureau combined Fort Lauderdale, West Palm Beach and Miami into one urban center of 5.0 million persons and Tacoma was combined with Seattle for a total population of 2.7 million persons.
  • The value of truck delay cost is lower than estimated in previous reports, which lowers the total congestion cost. The new values include the efficiencies gained by the trucking industry in the last 20 years, rather than a trend based on the Consumer Price Index.
  • Arterial street access management programs were added to the operational treatment list. These elements smooth traffic flow and reduce collisions through a variety of treatments such as deceleration lanes, restricting turns across medians and combining driveways.
  • The operational treatment effects are included for 2000, 2001 and 2002 mobility estimates. The data provide a better picture of the travel conditions in those three years. Unfortunately, the long-term trend analysis does not yet include this information.
  • The delay per traveler measure uses the number of persons beginning their travel using a motorized mode during the peak periods (6 to 9 a.m. and 4 to 7 p.m.). This is a more appropriate mobility measure than the previous delay per capita statistics.
  • The Annual Report seeks to provide the best estimate of travel conditions for each year. This year, as in other years, some previous statistics were slightly modified based on better understanding of trends and updated

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2004 Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader
2004 Urban Mobility Report: Six Congestion Reduction Strategies and Their Effects on Mobility PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

The 2003 Annual Urban Mobility Report

What is New for this Year?
  1. We have added the effect of three widely implemented operational treatments, public transportation service and high-occupancy vehicle lanes to the 2000 and 2001 mobility estimates. This change allows an examination of the effect of more types of improvements, allows a more thorough use of the available data and is another step in improving the mobility statistics. A separate report details these analyses and is posted on the Mobility Report website.
  2. We have chosen to present the data in population groups to better illustrate the mobility trends for areas of similar population. The mobility levels that might be expected in urban areas are more related to cities of similar size than to the full group of 75 cities. The statistics and methodology descriptions are still included along with much more information in Appendix A and on the website: http://mobility.tamu.edu.
  3. We present more information about the reliability side of urban mobility. This is not a comprehensive treatment, and more information is available in the 2001 Mobility Monitoring Report (http://mobility.tamu.edu/mmp) (1). The variation in travel times is an important element of congestion, and might be a more solvable problem than the regular overcrowding of roadways. Data to inform this discussion, however, is not as available as it is for average or estimated conditions.
  4. We have improved the speed estimation procedure and the incident delay factors. New computer simulations have been used to estimate the effect of vehicle breakdowns and collisions. Future changes in estimating the effects of operational improvements (see #2) will also likely affect the methods we use to estimate speeds and delay in the next several years. But simplifying assumptions and estimating procedures will be needed until more data collection programs are deployed.
  5. Delay per person and the travel time index indicate somewhat different conclusions about mobility. This trend will be watched to see if it continues and the potential causes will be examined, but it appears that there are some differences that are the result of actions and policies rather than random occurrences.

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2003 Annual Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader
2003 Urban Mobility Report: Volume 2 PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

The 2002 Urban Mobility Report

What is New for this Year?
  1. We have chosen to emphasize the mobility ISSUES and what we might be able to learn from the data this year. The statistics and methodology descriptions are still included along with much more information on the website: http://mobility.tamu.edu Issues and trends dominate this year’s report, however. The 19-year history of the database and the coming re-authorization of the federal transportation legislation provided the impetus to move away from a simple reporting of the numbers, to a slightly deeper attempt to understand what the data say.
  2. We have examined the "SOLUTION" side of urban mobility in more detail than in the past. This is not a comprehensive treatment, and more information will be published in the fall of 2002. Operational improvements and high-occupancy vehicle treatments are included in this report. The Fall 2002 report will provide a more integrated look at the urban transportation system—incorporating the effects of many improvement types into the Travel Time Index statistics.
  3. We have improved the SPEED ESTIMATING procedure. Using the new computer models that simulate traffic conditions and the more extensive traffic monitoring data we have collected, the relationships between traffic volume and speed are closer to the real world experience. Future changes in estimating the effects of operational improvements (see #2) will also likely affect the methods we use to estimate speeds and delay in the next several years. But simplifying assumptions and estimating procedures will be needed until more data collection programs are deployed.
  4. The improved speed estimates have resulted in LESS DELAY than we have previously estimated. This does not mean that congestion is not a problem; in fact, the trend remains the same—congestion increasing in every city size category. It means that the time penalty for peak period trips is not as great as previously estimated. This is primarily the result of the large volume of trips using the off-peak direction of the roadway to travel at speeds close to the speed limit. The measures for all years of the study are recalculated with the new trends.
  5. DELAY PER PEAK TRAVELER is a new mobility measure. We have used commuting surveys to estimate the number of travelers using the roads during the peak period, and divided the annual delay estimates by those people. This provides a more realistic idea of the amount of extra time that motorists spend traveling during peak hours.

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2002 Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

The 2001 Urban Mobility Report

What is Different About This Year’s Report?

The layout of the report is somewhat different this year. This report will focus less on the data tables and more on the issues addressed by the data. Many of the "issues" associated with urban mobility are discussed with some important trend or magnitude information shown by the data tables. The individual urban area information—all of the tables included in past reports—are included in an appendix to this report with links from each "issue" to the relevant tables.

New Measure

One important additional measure used in this report is the Travel Time Index (TTI)—a comparison of total travel time in the peak to travel time in free flow conditions. The TTI is different from the Travel Rate Index (TRI) because it includes delay from both heavy traffic demand and roadway incidents. The TRI only focuses on delay caused by heavy traffic demand. The TTI and TRI each illustrate the effect of a range of transportation improvements and address a central concern of urban residents—time it takes to travel in the peak periods.

New Methodology

A 1986 report (1) from FHWA summarized an analysis package to calculate freeway delay using the Highway Performance Monitoring System (HPMS) database. The program used travel and roadway information from each urban area to calculate both the recurring and incident delay that would result from the traffic levels on the roadways. The program simulated delay conditions on an urban freeway by generating incidents based on incident pattern data from a few U.S. cities from the 1960s and 1970s. The traffic incidents generated in the program could range from a breakdown on the roadway shoulder to a full freeway closure for an hour or more. The ratios of incident delay to recurring delay calculated in the FHWA report were used in previous Urban Mobility Study reports. In the latest Urban Mobility Study report, the FHWA program has been replicated so that the ratios can be updated annually with the current travel and roadway information. Thus, any changes in roadway configuration—such as more or fewer freeway breakdown lanes—will be reflected in the incident delay in the report.

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 2001 Urban Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

The 1999 Annual Mobility Report

1999 Annual Mobility Report — What's New This Year?

This report broadens the coverage of previous reports by including more information on mobility measures. The study began several years ago with a few measures, a few urban areas and a focus on roadway congestion measures. All of these have been expanded to more completely address urban mobility in the U.S.

  • One significant change in this report is the use of the Travel Rate Index (TRI)—a comparison of travel time in the peak to travel time in free flow conditions—instead of the Roadway Congestion Index (RCI). The TRI can illustrate the effect of a broader range of transportation improvements and addresses a central concern of urban residents—the time it takes to travel in the peak periods.
  • For the first time in this report series, the effectiveness of an operational improvement (HOV lanes in Houston) was included in the analysis. Additionally, the effectiveness is shown at both the areawide and individual freeway levels. The versatility of the new methodology is also shown in the case study of the Houston HOV lanes with speed data collected from the freeways in Houston substituted for estimated speeds. The hope for future reports is that with more and better travel speed data being collected, the speed data collected from operating freeways can be used to replace estimated data.
  • The most significant change to the current methodology is the addition of a fifth congestion level labeled "extreme." Because of the inclusion of the extreme category, some shifts in the estimated speeds for each of the congestion levels have occurred. These new estimated speeds have caused the average calculated speed to fall from previous levels in some areas and to increase in others, depending on the traffic density of the sections of roadway within each urban area.
  • The congestion estimation methods have particular importance when urban boundaries are redrawn due to realignments or when local agencies update the boundary to account for urban growth. These changes may significantly change the size of the urban area, which also causes a change in system length, travel and mobility estimates. When the urban boundary is not altered every year in fast growth areas, some data items take on a "stair-step appearance." Significant changes that are caused by the data compilation methods are addressed by altering statistics to present a trend closer to actual experience for each year. This may cause some areas to move up or down in the rankings in some of the measures.

CAUTION: Do not compare data or performance measures from two different reports to identify trends. (more details)

The 1999 Annual Mobility Report PDF document - For best results, view PDF files with the most recent version of the Adobe Acrobat Reader

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