2. 2010 © CEOs for CITIES 2
KEY FINDINGS
The secret to reducing time Americans spend in peak hour
traffic has more to do with how we build our cities than how
we build our roads.

3. 2010 © CEOs for CITIES 3
DISTANCE MATTERS
! In nation’s cities largest, typical traveler spends
200hr/yr in peak period travel
! But in best performing cities, travelers spend 40
fewer hrs in peak traffic
! Why? They travel shorter distances

4. 2010 © CEOs for CITIES 4
LONGER TRIP
DISTANCES
AND SPRAWL
SHAPE TRAVEL
TIMES

5. 2010 © CEOs for CITIES 5
A VERY DIFFERENT PICTURE
LONGEST PEAK HOUR TRAVEL
TIMES
Nashville-Davidson TN
Oklahoma City OK
Birmingham AL
Richmond VA
HOURS
284
252
245
242
RANK
1
2
3
4
UMR RATE
31
38
34
44
SHORTEST PEAK HOUR TRAVEL
TIMES
New York-Newark NY-NJ-CT
Sacramento CA
Chicago IL-IN
HOURS
122
136
163
RANK
46
48
51
UMR RATE
14
23
21

6. 2010 © CEOs for CITIES 6
ROADMAP
1. The Urban Mobility Report
2. Travel Time Index is flawed concept
3. UMR overestimates congestion
4. Fuel economy estimates contain errors
5. Developing better measures

7. 2010 © CEOs for CITIES 7
THE URBAN MOBILITY REPORT
! Produced since 1982 by
Texas Transportation
Institute
! Provides estimates and
rankings of congestion

8. 2010 © CEOs for CITIES 8
UMR CLAIMS
! Congestion is a big problem
– 46 hrs of delay per person per yr
! It wastes lots of energy
! It’s getting worse
! It costs us a lot of money
– $750 per person up from $290 in 1982

9. 2010 © CEOs for CITIES 9
UMR REALITY
! Impact of distance on travel times ignored
! UMR rates areas “less congested” even if residents have
to travel farther and longer
! Congestion estimated from unattainable ideal
! Speeds estimated from inaccurate model, mechanically
converting higher volumes into slower speeds
! Other evidence shows commute times have not increased
! Fuel economy incorrectly estimated, overstating costs

10. 2010 © CEOs for CITIES 10
A FLAWED CONCEPT:
THE TRAVEL TIME INDEX (TTI)
! How much additional time does it take to travel a given
distance at peak vs off-peak
! Example:
– Trip takes 20 min off-peak (free flow)
– Trip takes 25 min at peak
– TTI = 25/20 = 1.25
– 5 min of delay

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PROBLEMS WITH TTI
! An unrealistic baseline
– No one expects or can achieve zero
delay/free-flow in the peak hr
! TTI ignores variations in travel distances among
metro areas

12. 2010 © CEOs for CITIES 12
IS CHICAGO TRAFFIC REALLY
WORSE?
COMPARISON
Average Trip
Un-congested Travel Time
Delay
Total Travel Time
TRAVEL TIME INDEX
CHARLOTTE
19mi
38.4min
9.6mi
48.0mi
1.25
CHICAGO
13.5mi
22.8mi
9.8min
32.6mi
1.43

13. 2010 © CEOs for CITIES 13
UMR OVERESTIMATES CONGESTION
! No direct observation of travel time
! A bad model for estimating travel time
! UMR results don’t square with other measures

14. 2010 © CEOs for CITIES 14
WEAK BASIS FOR SPEED
ESTIMATES

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CHECKING UMR VALIDITY
! Do UMR estimates square with other data on variations in
travel over time and space?
– Inrix: Real time speed data
– NHTS: Comprehensive travel survey data
– Census/ACS: Reported journey-to-work
travel time data

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NATIONAL SURVEY SUGGESTS
TRAVEL TIME, ADJUSTED FOR
DISTANCE, ACTUALLY DECLINED

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UMR NOT CONSISTENT WITH INRIX
The average UMR estimate in 70% higher than the average INRIX observation:
UMR = 1.24 INRIX = 1.14

18. 2010 © CEOs for CITIES 18
FUEL CONSUMPTION ESTIMATES
BASED ON OUTDATED STUDY
! RAUS study done in 1981
! Data: 1973-76 GM cars av 13.6mpg
! Fuel economy estimates
“The above relationship is
good only for speeds up to
about 35mph”

19. 2010 © CEOs for CITIES 19
UMR v. DOE FUEL ECONOMY
CURVES

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TOWARD BETTER MEASURES OF
URBAN TRANSPORTATION SYSTEMS
TWO KEY TASKS
! Correcting the UMR
! Developing new measures that emphasize accessibility

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CORRECTING THE UMR ESTIMATE
! Recompute UMR, assuming
– Realistic baseline
– Better travel time data (Inrix)
– Lower travel time costs
– Drop fuel model
! Reduces UMR cost estimate 70%
! UMR overstates by $49 billion

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A NEW FOCUS
! Shift to accessibility measures
! Start with shorter distances actually traveled in many
metro areas
! Use a realistic baseline
– What is actually attained in best of class
metro areas
– Look at 90th percentile performers
! Quantify time, energy, and economic costs of sprawl-
lengthened commute travel

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THE ROLE OF
LONGER TRIP
DISTANCES

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THE PAYOFF
! If every one of the top 50 metro areas achieved
same level of peak hr travel distances as best
performing cities, their residents would drive about
40B fewer mi/yr and use 2B fewer gal of fuel, at
savings of $31B annually.

25. 2010 © CEOs for CITIES 25
SOME CITIES HAVE MADE
PROGRESS
THE UMR VIEW: Congestion got worse
Travel Time Index
1982
1.07
2007
1.29
THE REALITY: Trips and travel time got shorter
Average Trip
Travel Time
1982
19.6mi
53min
2007
16.0mi
43min

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BUILDING A BETTER MEASURE
! Emphasize access to destinations
! Add measures of land use & trip distance
! Incorporate better data
! Adopt open, multidisciplinary process
! Aim to guide policy and assess investments

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CONCLUSIONS
! The Travel Time Index (TTI) is a misleading guide to
assessing transportation system performance and costs
and inherently rewards sprawl and penalizes compact
development
! The UMR methodology is flawed, and its results can’t be
reconciled to real world observations
! Sprawl, not congestion, is the bigger source of time loss,
energy waste and excess costs in most metro areas
! New measures that emphasize accessibility should guide
our transportation policy