l02: establishing monitoring programs for mobility and ... · 117257821/28/2011 12:24 22 us50-e...

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 3:53 10 South 5.8 - 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 18:53 10 South 3.5 - 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




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

l02: establishing monitoring programs for mobility and ... · 117257821/28/2011 12:24 22 us50-e...

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