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Establishing Monitoring Programs for Mobility and Travel Time Reliability (L02) SHRP2 Tuesdays Webinar Series August 6, 2013
Establishing Monitoring Programs for Mobility and Travel Time Reliability (L02) SHRP2 Tuesdays Webinar Series August 6, 2013
Today’s Panelists and Moderator
• Pat Hu, RITA and Bureau of Transportation Statistics, USDOT [email protected]
• Matt Miller, Transportation Research Board [email protected]
• Bob Rupert, Federal Highway Administration [email protected]
• George List, North Carolina State University [email protected]
• Mename Hedhli, Transportation Research Board [email protected]
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1 TRB’s SHRP 2 Tuesdays Webinar - August 6 , 2013
– $232 million, federally funded research program to address critical transportation challenges
• Making highways safer • Fixing deteriorating infrastructure • Reducing congestion
– Managed by TRB of the National Academies
– Collaborative effort of TRB, AASHTO, and FHWA
– Originally operates from 2006 to 2013 – extended to 2015
– Aims to advance innovative ways to plan, renew, operate, and improve safety on the Nation's highways
WHAT IS SHRP2 ?
FOUR RESEARCH FOCUS AREAS
Safety: to prevent or reduce the severity of highway crashes by understanding driving behavior.
Renewal: to renew aging infrastructure through rapid design and construction methods that minimize disruption and produce long-lived facilities.
Capacity: to integrate mobility, economic, environmental, and community needs into the planning and design of new highway capacity.
Reliability …..
RELIABITY FOCUS AREA OBJECTIVE
“To provide reliable travel times by preventing and
reducing non-recurring congestion” •i.e., reduce the variability of travel time through reducing the underlying causes
THE SEVEN CAUSES OF UNRELIABILITY
The Reliability Focus Area research has attributed variability in travel time to seven primary causes
1. Incidents 2. Weather 3. Work zones 4. Fluctuations in demand 5. Special events 6. Traffic control devices 7. Inadequate base capacity
CHANGE IN POLICY FOCUS FROM AVERAGE TO VARIABILITY IN TRAVEL TIME
Travel Time
Past Focus on Average Travel Time
Now Focus is on Variability
Probability
Avg
RELIABILITY RESEARCH PROMOTE ADVANCES IN THESE THEME AREAS
Organizational strategies and processes
New data collection and analysis tools
Understanding and influencing driver behavior
Improving planning, programming and design
Adopting new ideas and innovations
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TRAVEL TIME RELIABILITY MONITORING SYSTEM (TTRMS)
A Travel Time Reliability (TTR) Monitoring System helps Operating Agencies
1. Monitor system performance 2. Understand the impacts of the factors that influence TTR 3. Provide credible information to the system users about TTR 4. Make better decisions to improve Reliability
Monitor Understand Inform Decide
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Objectives of the project 1. Provides guidance on developing and using a Travel Time
Reliability Monitoring System (TTRMS) 2. Provides guidance on Integrating data for reliability analysis 3. Provides methods for analyzing causes and locations of unreliable
performance that help to identify possible mitigating strategies
THE PROJECT “ ESTABLISHING MONITORING PROGRAMS FOR MOBILITY AND TRAVEL TIME RELIABILITY “
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Measure
Characterize
Identify
Understand
….. How travel time varies over time and collect related data …... the nature of Reliability …… the sources of congestion ……how to improve reliability
THE PROJECT “ ESTABLISHING MONITORING PROGRAMS FOR MOBILITY AND TRAVEL TIME RELIABILITY “ The four primary functions:
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Methodology
THE PROJECT “ ESTABLISHING MONITORING PROGRAMS FOR MOBILITY AND TRAVEL TIME RELIABILITY “
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Pre Publication Final Report and Guidebook are available on TRB’s website
Final Report Guidebook
THE PROJECT “ ESTABLISHING MONITORING PROGRAMS FOR MOBILITY AND TRAVEL TIME RELIABILITY “ Publications
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Thank you for listening
SHRP2 Tuesdays
• Upcoming webinars • August 20: Managing Risk in Rapid Renewal Contracts (R09)
• September 17: Incorporating Reliability Performance Measures into the Transportation Planning and Programming Process (L05)
• September 24: Modular Pavement Technology (R05)
• October 1: Integrated Advanced Travel Demand Model with Mode Choice Capacity and Finely-Grained, Time-Sensitive Networks (C10)
• Learn about future webinars at www.TRB.org/SHRP2/webinars
15 TRB’s SHRP 2 Tuesdays Webinar - August 6 , 2013
PILOT TESTING 5 CORE ANALYTICAL PRODUCTS (PROJECT L38)
Data Collection
Analysis
Decision
Establishing a Travel Time Reliability Monitoring System (L02)
Reliability in Planning and Programming (L05)
Effects of Designs (L07) Highway Capacity methods (L08) Benefit-Cost Analysis (C11)
PROJECT DELIVERABLES
• The key pilot test deliverable will be a final summary report providing detailed findings on:
– Technical feasibility of the suite of analytical products – List of potential refinements – Whether outputs were understood by decision makers
and regarded as credible – Whether the recommendations resulting from the
products were accepted and scheduled for implementation
FOUR PILOT TEST SITES
System Metrics; Southern California Association of Governments; Caltrans Testing All 5 products
Minnesota Department of
Transportation; SRF Corporation
Testing All 5 products
Florida International University; Florida Department of Transportation District 6; HNTB Corp Testing 4 products, not testing economic impact analysis
Washington State Department of
Transportation; University of Washington Star Lab
Testing All 5 products
Four Pilot Test Sites
EXAMPLE PILOT: FLORIDA INTERNATIONAL UNIVERSITY
This pilot will work closely with FDOT District 6 and regional stakeholders in order to integrate and test SHRP 2 products within the following data collection and integration tools: — ITSDCAP: ITS Data Capture and Performance Management Tool — IRISDS : Integrated Regional Information and Decision Support System
Florida District 6
ITSDCAP: ITS DATA CAPTURE AND PERFORMANCE MANAGEMENT TOOL
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IRISDS : INTEGRATED REGIONAL INFORMATION AND DECISION SUPPORT SYSTEM
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FINAL EVALUATION WILL FOCUS ON:
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1. Examining improvement strategies with inputs from project
stakeholders to identify potential alternative mitigation actions
2. Comparing the reliability of the I-95 corridor before and after implementing various strategies
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Thank you for listening
Matthew A Miller , TRB-SHRP2
Establishing Monitoring Programs for Mobility and Travel Time Reliability
(Project L02)
Bob Rupert Federal Highway Administration
Office of Operations
Reliability Vision
TRB’s SHRP 2 Tuesdays Webinar - August 6 , 2013
Why Does FHWA Focus on Improving Operations?
• To reduce / manage impacts of congestion • To keep people and commerce moving – a
healthy economy needs a reliable transportation system
• To improve the safety and sustainability of the highway system
• To make more cost effective investment of limited resources
• To promote a more proactive approach
2
Operations activities…
• Influence travel demand (how much, when, where) • Effectively manage traffic resulting from travel demand • Anticipate and respond to planned and unplanned
events (traffic incidents, work zones, bad weather, special events)
• Provide travelers with high quality traffic and weather information
• Ensure that the unique needs of the freight community are considered and included in all of the above
3
Proactively Operating the Transportation System Requires:
• Real-time and forecasted information • Measuring / monitoring performance • Good analytical foundation / tools • State of the art technologies and strategies • Integration across system elements,
jurisdictions, and modes • An organization and workforce capable of
managing all of the above 4
Link to L02
• Lots of data & information, but – How to make sense of it all – How to make it meaningful – How to make it useful
• Reliability Monitoring Systems can help – Monitor performance of the system – Visualize the impacts of the factors that influence
reliability – Provide means for communicating about reliability – Influence decisions related to improved reliability
• Learn from the pilot tests of the Reliability Analytical Products
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Conclusion
• Effective operation of the transportation system provides significant benefits
• Operating the system proactively is the key concept in realizing these benefits
• Implementation of SHRP2 reliability products will be vital to achieving the vision for proactive transportation system management and operations
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Thank you! Bob Rupert, Team Leader Transportation Information Management FHWA Office of Operations [email protected] 202-366-2194
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Concepts, Training Materials,
Processes and Practices
SHRP2 Tuesdays Webinar Series: Establishing Monitoring
Programs for Travel Time Reliability
August 6, 2013
George List / NC State
Presentation Organization (Three Parts)
• How to set up and use the monitoring system
• Skills needed and how to use them
• Example analyses
2
Part 1: Set Up the System • Develop the system modules (see below)
• Create links to data feeds • system sensors, individual vehicle data, causal factors
3
Note: Can be stand-alone or attached to an
existing TMC System.
Define the Segments and Routes • Use spots in-between interchanges and intersections
• TMC boundaries on freeways, mid-block locations on arterials
4
Segment
Route
Segments on a Freeway
5
Segment Definitions
Segment breakpoints
Notes
• Segments begin and end in-between the interchanges
• At least one data source exists for each segment
• Breakpoints are at TMC segment boundaries
Monitoring locations
Acquire Travel Time Data
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System Detector
Data
Vehicle Data
(AVI, AVL)
Get Good Timestamps and Locations
7 7
AVI: Timestamps AVL: Timestamps
and locations
Impute Missing Data
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Detectors: Occupancies,
Volumes, and Speeds
Detectors: Speeds (single loops)
AVI and AVL: Segment Times
Filter Trip Times to get Travel Times
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Raw Data
Filtered Data
Note: Filter very carefully to capture transients and remove noise
Get Non-Recurring Event Data
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DataTime Visib Wind Wind Spd Gust Spd Precip Events Cond
1/28/2011 0:53 10 Calm Calm - N/A Clear
1/28/2011 1:53 10 South 3.5 - N/A Clear
1/28/2011 2:53 10 Calm Calm - N/A Clear
1/28/2011 3:53 10 South 5.8 - N/A Clear
1/28/2011 4:53 10 Calm Calm - N/A Clear
1/28/2011 5:53 10 Calm Calm - N/A Clear
1/28/2011 6:53 10 Calm Calm - N/A Clear
1/28/2011 7:53 10 Calm Calm - N/A Clear
1/28/2011 8:53 10 Calm Calm - N/A Clear
1/28/2011 9:53 10 Calm Calm - N/A Clear
1/28/2011 10:53 10 NNE 3.5 - N/A Clear
1/28/2011 11:53 10 NE 4.6 - N/A Clear
1/28/2011 12:53 10 NNE 5.8 - N/A Clear
1/28/2011 13:53 10 NNE 9.2 - N/A Clear
1/28/2011 14:53 10 Variable 4.6 - N/A Clear
1/28/2011 15:53 10 SSW 5.8 - N/A Clear
1/28/2011 16:53 10 SSW 3.5 - N/A Clear
1/28/2011 17:53 10 Calm Calm - N/A Clear
1/28/2011 18:53 10 South 3.5 - N/A Clear
1/28/2011 19:53 10 Calm Calm - N/A Clear
1/28/2011 20:53 10 South 8.1 - N/A Clear
1/28/2011 21:53 10 SSW 3.5 - N/A Clear
1/28/2011 22:53 10 Calm Calm - N/A Clear
1/28/2011 23:53 10 Calm Calm - N/A Clear
1/29/2011 0:53 10 Calm Calm - N/A Clear
Incident Id Start Time Dur (min) Freeway Abs PM Location Description
11724869 1/28/2011 3:50 41 US50-E EB US50 ON 15TH ST OFR 1182 - Collision - Non Injury
11724935 1/28/2011 5:45 7 US50-E EB US50 ON POWER INN RD OFR 1125 - Traffic Hazard
11724958 1/28/2011 6:02 27 US50-E 5.89 EB US50 ON 34TH ST OFR 1182 - Collision - Non Injury
11725029 1/28/2011 6:55 0 US50-E EB US50 JEO EL DORADO HILLS BLVD 1126 - Disabled Vehicle
11725175 1/28/2011 7:57 2 US50-E 31.755 EB US50 JWO BASS LAKE RD 1125V - Traffic Hazard - Vehicle
11725425 1/28/2011 9:33 22 US50-E 17.601 EB US50 JWO SUNRISE BLVD 1125 - Traffic Hazard
11725782 1/28/2011 12:24 22 US50-E 298.514 EB US50 JWO SB SR99 1125 - Traffic Hazard
11725927 1/28/2011 13:17 0 US50-E 64.033 EB US50 AT HAZEL VALLEY RD 1183 - Collision - No Further Details
11726010 1/28/2011 13:49 10 US50-E EB US50 AT FRONT ST 1125V - Traffic Hazard - Vehicle
11726196 1/28/2011 14:51 59 US50-E 10.488 EB US50 JWO NB WATT AV 1183H - Collision - Blocking Lane - No Details
11726269 1/28/2011 15:11 23 US50-E EB US50 JWO POWER INN RD 1126 - Disabled Vehicle
11726302 1/28/2011 15:23 0 US50-E EB US50 JWO 48TH ST 1126 - Disabled Vehicle
11726453 1/28/2011 16:03 19 US50-E EB US50 JWO POWER INN RD 1179H - Collision - Ambulance - Blocking Lane
11726532 1/28/2011 16:29 0 US50-E 10.688 EB US50 AT NB WATT AV 1126 - Disabled Vehicle
11726568 1/28/2011 16:39 0 US50-E 26.68 EB US50 JWO E BIDWELL ST 1125 - Traffic Hazard
11726655 1/28/2011 17:04 2 US50-E 8.83 EB US50 JWO HOWE AV FIRE - Fire
11726737 1/28/2011 17:29 14 US50-E 5.89 EB US50 ON 34TH ST OFR 1125V - Traffic Hazard - Vehicle
11727378 1/28/2011 22:21 60 US50-E 26.88 EB US50 AT E BIDWELL ST 1126 - Disabled Vehicle
11727377 1/28/2011 22:25 0 US50-E 29.838 EB US50 JEO LATROBE RD 1126 - Disabled Vehicle
11727559 1/29/2011 1:25 20 US50-E 298.384 EB US50 JWO NB SR99 1126 - Disabled Vehicle
11727710 1/29/2011 6:12 1 US50-E 298.514 EB US50 JWO SB SR99 1125 - Traffic Hazard
Weather
Incidents and Other Events
Note: Be sure to capture incident events that happen nearby as well as on
the subject facility. Explanatory events may not be on the facility of interest.
• Location
• Start time
• End time
• Lanes blocked
• Max queue length
• Description
Label the Data using Regimes
• Regime: (nominal congestion level, non-recurring event)
• Clarifies causal factor impacts
• Makes it possible to separate non-recurring event impacts from recurring congestion impacts
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None Low Moderate High
Incidents
Weather
Work Zones
Demand Fluctuation
Special Events
Traffic Control
Low Base Capacity
Nominal Congestion Level
Analysis Regimes
Non-Recurring Event Condition
Seven
Factors
None
Note: Time of day, season, region, facility
types, etc. are related, but separate thoughts.
Add the Non-Recurring Event Labels
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A
B
Average travel times for
every 5 minutes on
weekdays for a year
Add Nominal Congestion Level Labels
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22 2
1
1 n
r r r i i
i
where x r x rn
We used the semi-standard deviation*
*other options include TTI, PTI, BT, τrms
5-minute average travel rates for normal
operation (no non-recurring event) on
weekdays for a year
Define the Analysis Setting
• First perspective:
• Periods of time during a day (e.g., AM peak, PM peak, midday, a
specific hour, a specific 5 minutes), across a time span (e.g., a
season, a year, multiple years, looking at how the distributions of
average travel times (or average rates) vary by time of day, regime,
etc. (could be the median travel time or some other percentile)
• Second perspective:
• A period of time (e.g., the AM peak) on a specific day (e.g., last
Friday), or set of days (all Fridays in the summer) to see how the
distributions of individual vehicle travel times vary as time
progresses (e.g., how the distributions change during an incident or
during peak congestion)
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Analyze Performance
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• More vertical is better
• Further left is better
• Label by regime
High percentiles are
difficult to manage and
mitigate because they
are likely to be caused
by infrequent events
CDFs of individual vehicle
travel rates during regimes
Find Mitigating Strategies
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• Weather advisories
• Drainage
• Pavement markings
• Event management
(High, Weather)
(High, Incidents)
(Moderate, Special Events)
(Moderate, Weather)
CDFs of individual vehicle
travel rates during regimes
Assess Improvements Across Time
17
• Compare CDFs
• Look for shifts left and up
Year 1
Year 2
Year 3
Hypothetical Route
CDFs of average travel
times across a year
Summary
Set up the system o Hardware and software
o Define segments, routes, etc.
Acquire data o Spot speeds (e.g., loops)
o Vehicle trajectories
o Non-recurring event data
Prepare for analysis o Add non-recurring event labels
o Add congestion level labels
o Group data by regime
Analyze and take action o Define the analysis setting
o Spot mitigating strategies
o Implement
o Assess impacts
o Refine and iterate
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Part 2: Skills
• How to work with the data
• PDFs and CDFs
• System data and vehicle data
• Travel times and rates (including route-level values)
• AVI and AVL travel times
• Imputation
• How to define the analysis conditions and performance
metrics
• How to spot the impacts of congestion and incidents and
diagnose why travel times change
• How to pick response actions and monitor improvements
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Work with PDFs and CDFs • PDFs and CDFs provide the answers
• The raw CDFs and PDFs provide the best insights
• Fitting to parametric distributions is not that helpful
• The PDFs help spot regimes (modes)
• More peaks more regimes (modes)
• Height frequency of occurrence / significance
• The CDFs are useful for comparisons
• More vertical is better
• Further left is better
• Less bumpy is better
• Go back and forth between the two
• PDFs can be created from CDFs and vice versa
20
Use PDFs to Spot Regimes
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CDFs of average travel
times across multiple days
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0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 2 4 6 8 10 12 14 16 18 20
Cu
mu
lati
ve P
erc
en
tage
Travel Time (min)
Travel Time CDFs on I-5 NB in Sacramento for Four One Hour Time Periods
7-8AM 1/27/11
5-6PM 1/24/11
8-9AM 2/2/11
7:30-8:30AM 2/8/11
Use CDFs to Compare Performance
CDFs of individual
vehicle travel times
Use CDFs to Study Factor Impacts
23
Jordan Road
NY-4
5 6
1
2 3
North
3 2
CDFs of individual
vehicle travel rates
Use CDFs to see System Dynamics
24
CDFs of individual
vehicle travel times
25
Use CDFs for Distribution Trends
Successive CDFs plotting
selected percentiles. The
mean and standard deviation
are also plotted.
CDFs of individual
vehicle travel times
26
Use CDFs to Identify Actions
CDFs of individual
vehicle travel times
Use Travel Rates for Comparisons • Rate = distance per unit time
• Typical units: minutes/mile, seconds/mile
• Inverse of the space-mean speed
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Average travel rates for every 5
minutes on weekdays for a year
Route Times for AVI / AVL Data
• Add specific percentiles of the
segment-level times
• Red = actual
• Blue = synthesized
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PDFs of individual
vehicle travel times
Example: Route
Performance
29
• Pick origin and
destination
• Pick starting times
• e.g., every 5 minutes
• For every starting time
• Find the exiting time for
each segment
• Use that time as the
entering time for the next
segment
• Sum the segment times
Define the Analysis Context
• Data sources
• Individual vehicles, system detectors, or some combination
• Time span for the observations
• Multiple years, one year, a season, a week, a day, a peak period..
• Time period of interest
• Peak period, all congested hours, all Fridays……
• Temporal granularity for performance assessment
• Sets of vehicles, 1 minute averages, 5 minute averages, 15 minute
averages ……
• Metric(s) to use
• Travel rates, standard deviations, RMS rates, TTIs, PTIs, BTs…..
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Pick and Understand the Metrics
0
50
100
150
200
250
300
350
400
4.5 9.5 14.5 19.5 24.5 29.5
Travel Time (in Minutes)
Number of Trips (in Thousands) for a year or some other extended time span
Free Flow
Mean 95th
Percentile
99th
Percentile
Misery Time
Standard
Deviation
Buffer
Time
Planning
Time
Failure
Measure
Semi-Standard Deviation
RMS Travel Time
Source: Adapted from L08
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 2 4 6 8 10 12 14 16 18 20
Cu
mu
lati
ve
Pe
rce
nta
ge
Travel Time (min)
Travel Time CDFs on I-5 NB in Sacramento for Four One Hour Time Periods
7-8AM 1/27/11
5-6PM 1/24/11
8-9AM 2/2/11
7:30-8:30AM 2/8/11
Using the CDFs is
always very clear.
How Vehicle and System Data Relate
32
Illustrations
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0
5
10
15
20
25
0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 0:36:00 0:43:12 0:50:24 0:57:36 1:04:48 1:12:00
Trav
el T
ime
Relative Minutes
Bluetooth-Based Vehicle Travel Time Trends, I-5 Northbound, Sacramento
5-6PM 1/24/11
7-8AM 1/27/11
8-9AM 2/2/11
7:30-8:30AM 2/8/11
Part 3: Examples
• First location • San Diego, CA
• Hypothetical trips • From the I-5 / I-805 Split
• To National City
• Routes • I-5
• I-805 / CA-163 / I-5
• I-805 / CA(I)-15 / I-5
• Data • Average travel times every
5 minutes for weekdays
• From system detectors
• Time frame • All workdays for a year
34
Study the Time of Day Variations
35
Average rates for every 5
minutes on weekdays for a year
Study the Congestion Level Variations
36
Average travel rates for every 5
minutes on weekdays for a year
Add the Non-Recurring Event Labels
37
Average travel rates for every 5
minutes on weekdays for a year
Add the Nominal Congestion Labels
38
Average travel rates during normal operations (i.e., no non-
recurring event) for every 5 minutes on weekdays for a year
39
Study the CDFs by Regime and Route
CDFs by regime of average rates for every
5 minutes on weekdays for a year
40
Notice What CDFs are Worst
CDFs by regime of average rates for every
5 minutes on weekdays for a year
41
Identify Mitigation Strategies
CDFs by regime of average rates for
every 5 minutes on weekdays for a year
42
Unify the Ideas
Find the Biggest Impacts
43
Create the Unified Picture
44
Exhibit 1-1: Semi-Variances Each Regime for Three Routes in San Diego
A Second Example – Rural Arterial • US 50 / Placerville to South Lake Tahoe, Bluetooth data
• Winter
• All hours, all conditions (regimes)
45
Monitoring location
Extract Travel Times from Trip Times
46
Raw trip time
observations
Inferred
travel times
from careful
filtering Individual
vehicle travel
times
Create Regimes by Labeling
47
Note: In this case, the variations in congestion level were not that significant, so the
regimes were principally dependent on the non-recurring event conditions.
Find Mitigating Actions
48
• Snow detection and removal
• Lane markings and illumination
CDFs of individual
vehicle travel times
by regime
Summary
49
Set up the system o Hardware and software
o Define segments, routes, etc.
Acquire data o Spot speeds (e.g., loops)
o Vehicle trajectories
o Non-recurring event data
Prepare for analysis o Add non-recurring event labels
o Add congestion level labels
o Group data by regime
Analyze and take action o Define the analysis setting
o Spot mitigating strategies
o Implement
o Assess impacts
o Refine and iterate
Thank You / Questions
50
