The document discusses the evolution of transportation studies from the 1950s to the 21st century, highlighting the need for traffic impact studies (TIS) to consider transit service alongside auto traffic. It critiques the current emphasis on auto traffic metrics and advocates for improved transit service quality, suggesting new metrics and practices for TIS. The authors, including Michelle Derobertis, aim to redefine transportation success, emphasizing the importance of a balanced transportation system that accommodates all modes of transit.

1. Transportation Studies
in the 21st Century-
Incorporating All Modes
Michelle DeRobertis PE
Transportation Choices for
Sustainable Communities
Oakland CA

3. 1950’s till now, goal of Traffic Impact
Studies (TIS) was:
Accommodate Auto Traffic

4. Absurd Results of Tipping Scales in
Favor of Autos:
1. Inequitable Development Conditions
▫ First in pays least
▫ Last in pays most (or
changes project)

5. 2. SPRAWL

6. 3. Huge wide swaths of asphalt unused
for 22 hours a day

7. 22 hours of the day, roadway capacity is
unused

8. 4. Double Standard-

9. 21st Century Setting-
Political & Social Landscape is Changing

10. Fewer Teen Drivers 1983-2010
90
80
70
60
40
30
20
10
0
50
16
17
18
19
1983
2010
17 18
16 19

11. 21st Century Setting-:
CAR FREE Households
Are Increasing

12. Even State Laws Are Changing
▫ Many States now have GHG reductions targets
▫ California has a state law that prohibits vehicle
congestion from being considered significant
impact in Environmental Documents

13. Our Speakers
▫ Peter Albert, City of San Francisco
▫ Patrick Lynch Transpo Group,
Bellingham, Washington
▫ Doug Thompson, City of Boulder CO
▫ Michelle DeRobertis, ITE Transit Council

14. Michelle DeRobertis P.E.

15. Purpose of ITE Committee on Transit
and Traffic Impact Studies
Document whether and how:
▫ Transit Quality of Service is addressed.
▫ Traffic impacts on transit service and
operations is addressed.
▫ Transit providers are involved in the TIS
process.

16. State of the Practice Study
Methodology
▫ Survey practitioners on the state of the
practice on Transit and Traffic Impact Studies.
▫ Review of known traffic impact studies and
TIS guidelines to see how well they address
transit.
▫ Write a “State of the Practice” report to be
published by ITE.

17. Problem –
• Undue attention is given to the LOS of the
surrounding freeways and arterials
• Very little attention to the Transit Service
▫ Report may mention the number and frequency of
busses, but does not rate whether the existing transit
service is “good” or “adequate”
• Conclusion often is that Roadways are operating at
LOS F and “need improving” whereas the Transit
service just “is”.

18. Result of Lopsided Analysis
MORE CAPACITY FOR AUTO NO CHANGES TO TRANSIT

19. Current Transit QOS Measurements*
• Service Availability
▫ Spatial- where the routes are
▫ Temporal – hours of service, headways
▫ Capacity- function of vehicle size and headways (2)
• Comfort and Convenience
▫ Passenger load
▫ Average Speed -Travel Time (1)
▫ Reliability
▫ Safety and security
▫ Stations and stops

20. Possible Metrics for use in TIS
1. Travel time-
▫ Compare transit travel time to the site to auto-travel
time
Mitigation measures to improve travel
time
• Transit signal preemption
• Bus only lanes

21. Possible Metrics for use in TIS
2. Capacity
• compare capacity of traffic lanes serving a site to
the capacity of transit service
Mitigation measures to improve capacity
• Decrease headways
• more./larger train cars

22. SAN FRANCISCO MUNI-Frequency
Standards
Weekday PEAK BASE EVENING OWL
RADIAL 10 15 20 30
EXPRESS 10 - - -
CROSS-TOWN
15 15 20 30
FEEDER 20 30 30 --

23. GOAL: ITE TRANSIT & TIS COMMITTEE
STATE OF THE PRACTICE
RECOMMENDED PRACTICE
BETTER TRANSIT SERVICE
1
2
3

24. 21st Century Way of Thinking:
▫ System is not “failing” when there is auto
congestion; it is an indicator of a thriving
economy.
▫ Congestion indicates that more/better transit
is needed as well as bikeways/walkways.
▫ Level of Service Scale of A-F is wrong:
 Implies LOS A is optimal where as in fact it is means
there is excess capacity.
 In fact V/C ratio of 1.0 LOS F could be considered
ideal in the demand and capacity are balanced