GIS-Based Statewide Roadway and Area Risk Assessment Screening Tool
19
GIS-based Statewide Roadway and Area Risk Assessment Tool By Michael Martin 2016 Traffic Safety Conference College Station, Texas
-
Upload
texas-am-transportation-institute -
Category
Data & Analytics
-
view
66 -
download
2
Transcript of GIS-Based Statewide Roadway and Area Risk Assessment Screening Tool
GIS-based Statewide Roadway and Area Risk Assessment Tool
By Michael Martin
2016 Traffic Safety Conference
College Station, Texas
Overview
The Concept
The Process– Defining a Common Geography
– Calculating Relative Area Crash Risk Metrics
– Creating a Composite Ranking
Statewide Area Risk Examples
To compare crash risks for a commonly identifiable geography relative to:
- Population Size
- Vehicle-Miles Travel (VMT)
- High & Very High Risk VMT
The Concept
1,024
Independent School Districts
Commonly Identifiable Geography
Fatal & Incapacitating Injuries per 1,000 inhabitants
Area Risk Relative to Population Size
Roadway Risk Assessment
Crashes Assigned2010-2014 Crashes Assigned
to Roadway Segments
Traffic Volume Ranges Defined
Area Type Functional Class
Volume Ranges
(ADT)
Low Medium High
Urban
Freeways <75,000 75,000 – 150,000 >150,000
Arterials <25,000 25,000 – 50,000 >50,000
Collectors <5,000 5,000 – 10,000 >10,000
Local* 0 – 20,000
Rural
Freeways <30,000 30,000 – 60,000 >60,000
Arterials <15,000 15,000 – 30,000 >30,000
Collectors <5,000 5,000 – 10,000 >10,000
Local* 0 – 15,000
*- Only one volume group.
Traffic Volume Ranges DefinedCrashes per Mile vs. Traffic Volume (ADT) for
Rural Freeways
Low HighMedium
0
10
20
30
40
50
60
70
80
90
100
0 20000 40000 60000 80000 100000 120000 140000 160000
Cra
she
s p
er
Mile
Traffic Volume (ADT)
Inflection points where the relationship changes.
Crash Risk Categories Assigned
Area Type Functional Class
Volume Ranges
(ADT)
Low Medium High
Urban
Freeways <75,000 75,000 – 150,000 >150,000
Arterials <25,000 25,000 – 50,000 >50,000
Collectors <5,000 5,000 – 10,000 >10,000
Local* 0 – 20,000
Rural
Freeways <30,000 30,000 – 60,000 >60,000
Arterials <15,000 15,000 – 30,000 >30,000
Collectors <5,000 5,000 – 10,000 >10,000
Local* 0 – 15,000
*- Only one volume group.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 1 2 3 4 5 6 7 8 9 10
Per
cen
t o
f Se
gmen
ts
Crash Rate (Crashes per Million Vehicle-Miles)
Inflection points where the relationship changes.
Low
Moderate
HighVery High
Crash Risk Categories AssignedCumulative Percent of Segment vs. Crash Rate for
Medium Traffic Volume Rural Freeways
All 20 combinations of:- Area Types- Functional Classes- Volume Ranges
Roadway Risk Assessment
Area Risk Relative to VMT
Fatal & Incapacitating Injuries per 10,000 VMT
Area Risk Relative to High & Very High Risk VMT
Percent High & Very High Risk VMT of Total VMT
Ranked #1 for Highest Risk
Metric Rankings
High Risk
Low Risk
Composite Ranking
OrderedLeast-to-Greatest
Ranked
Top 10 ISDs
Roadway Crash Risk Assessment
Fatal & Incapacitating
Injuries
