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The Connectivity Declaration - Joe Cortright, President of Impresa
- 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
- 11. 2010 © CEOs for CITIES 11
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
- 15. 2010 © CEOs for CITIES 15
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
- 16. 2010 © CEOs for CITIES 16
NATIONAL SURVEY SUGGESTS
TRAVEL TIME, ADJUSTED FOR
DISTANCE, ACTUALLY DECLINED
- 17. 2010 © CEOs for CITIES 17
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
- 20. 2010 © CEOs for CITIES 20
TOWARD BETTER MEASURES OF
URBAN TRANSPORTATION SYSTEMS
TWO KEY TASKS
! Correcting the UMR
! Developing new measures that emphasize accessibility
- 21. 2010 © CEOs for CITIES 21
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
- 22. 2010 © CEOs for CITIES 22
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
- 23. 2010 © CEOs for CITIES 23
THE ROLE OF
LONGER TRIP
DISTANCES
- 24. 2010 © CEOs for CITIES 24
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
- 26. 2010 © CEOs for CITIES 26
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
- 27. 2010 © CEOs for CITIES 27
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