l02: establishing monitoring programs for mobility and ... · 117257821/28/2011 12:24 22 us50-e...
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L02: Establishing Monitoring Programs
for Mobility and Travel Time Reliability
Project Overview
For the:
L38 Preliminary Meeting
August 1, 2012
George List, NC State
Main Work Products
• A guidebook that describes how to develop a travel time
reliability monitoring system (TTRMS)
• Supporting methodologies
• Data processing and management
• Data analysis
• Causal factor assessment
• Validation of the methodologies
• Illustrations of how to use a TTRMS
2
Structure of the Monitoring System
• It requires new data feeds to capture data about the influencing
factors; it requires skill in statistical analysis to have greatest value
• It allows you to understand how much a system’s travel times vary,
what makes them vary, and (implicitly) what corrective actions
might help
3
Analysis Methodology Overview
4
• The analysis process
involves several steps
Both Vehicles and Facilities
Distribution of tv
for 7:05 PM on
Feb 25, 2011
20 min. 19 min.
21 min.
Midnight
Noon
Time of Day
TT-PDF for the
Segment / Route
Se
gm
en
t o
r R
ou
te
Non-recurring
event impacts
Travel times for
individual vehicles
Average travel times at a specific
time of day for different days
Distribution of tavg
for 7:05 PM
Measurement Points
• A clean topology is needed to get clean data
7
Monuments,
Segments, Routes
Imputation
• Clean and complete data are needed
• You are trying to monitor travel times at the 1-5 minute level
• You are monitoring variations across time, across distances, and
among vehicles
8
9
AVI - Timestamps
AVL – Locations and Timestamps
Passage Times
Extracting Travel Times
• Differentiating between trip- and travel-times is crucial
• Remove the trips with stops and side trips, or filter them out, but do
not interfere with incident detection
10
Constant Transitions During Peaks
• The travel time world is richly varied
11
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
Tra
vel 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
CDF Animations
12
13
Vehicular Variance Trends
Route Travel Times and Rates
14
τbc (sec/mi)
50 60 70 80 90 100 110
τab
(sec/mi)
60
80
100 8% 24% 5%
120 6% 21% 7% 1%
140 1% 7% 2%
160 1% 3% 2%
180 1% 2% 1%
200 2% 1%
220 1% 1%
240 1% 1%
260
280
300
>300
1
Use correlations
Use incidence matrices
Use cascading queues
Walk the time-space matrix
Operating Regimes • Regimes help clarify the cause-effect relationships
• Regime = (congestion condition + non-recurring event condition)
• Regime = consistent system behavior
• Reflects traffic conditions
• Supports intuitive understandings
• How many regimes you need is site specific
• The impacts from non-recurring events vary widely and depend on congestion
15
None Weather Incident
High
Demand
Special
Event
Work
Zone
Uncongested
Low
Moderate
High
Event
Congestion
Level
Reliability Regimes
Congestion Condition Labeling
16
22 2
1
1 n
r i r r i
i
x r and x rn
Non-Recurring Event Data
17
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
Non-Recurring Event Labeling
18
A
B
Causal Factor Analysis
19
Variations by Regime
20
Mitigating Strategy Identification
21
Portrayal and Data Storage • Working with PDFs and CDFs works great
• You can use the PDFs and CDFs to answer
every question
• Both are valuable, in different ways
• The raw CDFs and PDFs help the most with
insights
• Parametrically-based distributions aren’t really
helpful
• Non-parametric analyses are not difficult, they
lend insights that might otherwise be missed,
and they are intuitive
• You should store the CDFs
• They are easy to identify, easy to verify, and
intuitive
• The PDFs can be derived from them
23
Travel Rates
• It is valuable to study travel rates (travel times / unit distance)*
• They allow comparisons among facilities
24
* Not speeds
Thanks / Questions
25
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