Review of the Texas Transportation Institute (TTI) 2007 Urban Mobility Report

ByRonald F. Kirby

Presentation to Transportation Planning BoardOctober 17, 2007

2

Introduction

“Traffic Congestion continues to worsen in American cities of all sizes, creating a $ 78 billion drain on the US economy” –press release of the Urban Mobility Report.

• Report prepared by Texas Transportation Institute

• First report in 1982, and repeated every few years since

• Current report based on 2005 data

• Following slides will review methodology, limitations, and conclusions of the report; and compare the report findings with TPB’s congestion monitoring

program.

3

Methodology

•The data source for the calculations is the national Highway Performance Monitoring System (HPMS)

•The primary performance measure used to estimate congestion delay is the Roadway Congestion Index (RCI) which in simple terms is a ratio of demand (VMT) to supply (lane miles of roadway).

4

Methodology (cont’d)

•Other performance measures are: Percent of daily travel in congested conditions, travel speed, travel delay (recurring), incident-related travel delay (non-recurring), person delay, travel time index, wasted fuel, and congestion cost

•Travel delay is the sum of recurring delay and non recurring delay. Travel delay per person is the primary measure in the 2007 report used in the ranking of metropolitan areas reported widely in the press.

•In previous reports a Travel Time Index (TTI) (the ratio of travel time in the peak period to travel time under free flow conditions) was used to rank cities.

5

Methodology (cont’d)

•Methodology in the TTI reports has changed over time; 2007 report changes include

•Freeway speed estimate under congested conditions•Population estimates•Truck percentages for each road•Average of daily fuel prices

•The revised speed estimation procedure used in 2007 is based on average daily traffic and speed observations from 29 metropolitan regions, which resulted in the low speed threshold being raised from 20 mph to 35 mph (graphic shown on next slide)

6

Urban Mobility Report Speed Estimation Chart

Archived data based freeway speeds and daily volumes from twenty nine (29) metropolitan regions

UTMPS: TTI model used for estimating speed from daily traffic

7

Limitations

•The report estimates the average conditions across the entire metropolitan region

•For our region the report estimates 50% of VMT occur during congested conditions and, based on national averages, that congested speeds on freeways are 43 mph and on arterials are 25 mph

•The report does not provide any facility-, direction-, time- or location-specific information

•Even though the methodology has improved over time and attempts to include the impacts of transit, HOV, demand management and some operational improvements, it still cannot estimate performance on a specific corridor

8

TPB’s Congestion Monitoring Program - Freeways

•TPB has had a freeway and arterial highway congestion monitoring program since the 80’s

•The freeway program represents a comprehensive study of the entire freeway system for am and pm peak periods and identifies congestion by location, time, and intensity (including the top ten congested locations). Aerial photography has been employed since 1993 on a three year cycle

•The Impact of fixing bottlenecks such as the Wilson Bridge and the exit ramp to the Dulles Toll Road from the Capital Beltway can be studied, as shown on the next slide

9

I-495/95 Capital Beltway (Outer Loop) Morning 2005 Traffic Survey

Note: Number of lanes increased from 1 to 2 on the exit ramp from SB I-495 to WB VA 267

10

TPB’s Congestion Monitoring Program - Arterials

•Since 1999 a sample of arterial highways in the National Highway System has been monitored on a three year cycle

•Use of global positioning system (GPS) technology provides speed information every two seconds along the roads being studied and helps identify bottlenecks (next slide shows the results of the arterial survey along VA 7)

•The impacts of a signal optimization along certain corridors are noticeable in the survey, as are improvements carried out at bottleneck locations such as addition of turn lanes

11

Virginia Route 7 (Tour 1)Between Van Dorn Street and International Drive

LOS for PM Period

Nor

thbo

und

Sout

hbou

nd

N

PM

Pea

k P

erio

d

PM

Pea

k P

erio

d

C

C

E

D

C

D

B

D

D

E

B

D

Van Dorn

Beauregard

Carlin Springs

Sleepy Hollow

Washington St

Haycock Rd

International Dr

C

D

F

D

C

E

D

E

C

F

E

C

PM

Pe a

k H

o ur

PM

Pe a

k H

o ur

D

E

D

C

FY 0

4FY

01

FY 0

4

FY 0

1

FY 0

4

FY 0

1

FY 0

7

FY 0

1

B

C

C

C

B

B

C

E

D

C

E

B

D

F

D

C

E

Segment Length: 9.1 milesPeak hour: 5:00 – 6:00 pmPeak period: 4:00 – 7:00 pm

C

C

D

E

E

D

E

FY 0

4

C

D

E

E

C

E

FY 0

7

C

C

C

E

D

C

D

B B

D

D

E

B

C

D

C

E

D

C

FY 0

7

FY 0

7

NB Bottleneck

SB Bottleneck

12

TPB’s Congestion Management Process

•The Congestion Management Process (CMP) is a requirement in metropolitan transportation planning under SAFETEA-LU

•The CMP under development involves efforts to evaluate transportation system performance; define, analyze, implement, and assess strategies; and compile project-specific congestion management information

13

Conclusions

•Even though the methodology in the TTI report has improved over time, it still provides average conditions across a region and is not a substitute for a regional congestion monitoring program which can identify location, direction, and time specific problem areas

•The primary value of the report is not so much in the rankings but in studying how urban areas across the country are doing over time:

“Please do not place too much emphasis on small differences in the rankings”

“That is the conclusion of this report – congestion is worse in urban areas of all sizes”

14

Policy Implications for the Nation •Traditional federal and state funding sources such as the gasoline tax have not kept pace with needs, and much of the responsibility for adding capacity has shifted to local funding sources and tolls

• Discussions underway on reauthorization of federal transportation legislation, due by October 1, 2009 for federal FY 2010 - 2015

15

Two Commissions Established Under SAFETEA-LU

(1)National Surface Transportation Policy and Revenue Study Commission

• Charged with “completing a comprehensive study of the national surface transportation system and the Highway Trust Fund, then developing a conceptual plan, with alternative approaches, to ensure that this system continues to serve the needs of the United States”

(2) National Surface Transportation Infrastructure Financing Commission

• Charged with “analyzing future highway and transit needs and the finances of the Highway Trust Fund and making recommendations regarding alternative approaches to financing transportation infrastructure”

16

Activities and Schedule for SAFETEA-LU Commissions

(1) Policy and Revenue Study Commission

• Ten field hearings; 74–member “big ideas” panel of experts; seven public sessions in Washington, DC

• Report expected December 2007

(2) Infrastructure Financing Commission

• Four meetings in Washington, DC, two more scheduled

• Interim report expected December 2007, final report early 2008

17

Potential TPB Reauthorization Activities

• Review reports of national Commissions in early 2008

• Consider forming a Reauthorization Task Force to prepare a TPB policy brochure, as was done for SAFETEA-LU