Star Quality Ratings and Filtered Searching in Road Safety Features
Current and Upcoming Features
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Star quality ratings
•
Searching with filters
•
Recent features:
–
Reorganized navigation
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User guide with video tutorials
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State CMF lists
•
Upcoming features:
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Comparison tool
Star Quality Rating
Criteria
1.
Study design
2.
Sample size
3.
Standard error
4.
Potential bias
5.
Data source
Study Design
•
Methodology of the study
•
Excellent
: Statistically rigorous study design
with reference group or randomized
experiment and control
•
Fair
: Cross sectional study or other coefficient
based analysis
•
Poor
: Simple before/after study
Sample Size
•
Crashes, mile-years, site-years, miles, or sites
–
Ex: 8 miles for 5 years is 40 mile-years
•
Excellent/fair/poor
: Larger is better. Rating
depends on size of sample, with
considerations for study design.
Standard Error
•
Statistical indication of the reliability of the
CMF value
•
Excellent
: Significant at 95% confidence level
(SE=0.05, CMF=0.80)
•
Fair
: Significant at 90% confidence level but
not 95% confidence (SE=0.11, CMF=0.80)
•
Poor
: Not significant at 90% confidence level
(SE=0.20, CMF=0.80)
Potential Bias
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Any biases observed by the reviewer
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Ex: Makeup of the study site group, issues with
analysis or modeling, etc.
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Excellent/fair/poor
: Better rating for fewer
biases.
Data Source
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Diversity of the data used to develop the CMF
•
Excellent
: Diversity in States representing
different geographies
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Fair
: Limited to one State, but diversity in
geography within State (e.g., CA)
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Poor
: Limited to one jurisdiction in one State
Star Quality Rating
Using Filters
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Search “signal” (581 results)
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Filter for only 3,4, or 5 star CMFs (389 results)
•
Filter for only angle crash CMFs (38 results)
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Filter for only urban CMFs (24 results)
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Discuss all results, why various categories
appear
CMFs that look similar in search results
•
Search for “rumble”
•
Filter for “run off road” crash type and crash
severities of fatal, serious injury, and minor
injury
•
Expand shoulder treatments -> Shoulder
rumble strips -> Install shoulder rumble strips
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What makes the 1
st
and 2
nd
ones different?
•
Go to Details, see differences in road type and
division; AADT range; states of origin
Comparison
CMF = 0.64
CMF = 0.83
Comparison
CMF = 0.64
CMF = 0.83
Website Features
•
Recently added
–
Reorganized navigation
–
User guide with video tutorials
–
State CMF lists
•
Upcoming
–
Comparison tool
In this information-rich content, delve into the criteria of star quality ratings in road safety, including study design, sample size, standard error, potential bias, and data source diversity. Explore the methodology nuances for excellent, fair, and poor ratings in each category. Discover how to efficiently search and filter road safety data based on star ratings, with insights on using filters for specific CMFs like angle crashes and urban scenarios.
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Presentation Transcript
Current and Upcoming Features Star quality ratings Searching with filters Recent features: Reorganized navigation User guide with video tutorials State CMF lists Upcoming features: Comparison tool
Star Quality Rating Criteria 1. Study design 2. Sample size 3. Standard error 4. Potential bias 5. Data source
Study Design Methodology of the study Excellent: Statistically rigorous study design with reference group or randomized experiment and control Fair: Cross sectional study or other coefficient based analysis Poor: Simple before/after study
Sample Size Crashes, mile-years, site-years, miles, or sites Ex: 8 miles for 5 years is 40 mile-years Excellent/fair/poor: Larger is better. Rating depends on size of sample, with considerations for study design.
Standard Error Statistical indication of the reliability of the CMF value Excellent: Significant at 95% confidence level (SE=0.05, CMF=0.80) Fair: Significant at 90% confidence level but not 95% confidence (SE=0.11, CMF=0.80) Poor: Not significant at 90% confidence level (SE=0.20, CMF=0.80)
Potential Bias Any biases observed by the reviewer Ex: Makeup of the study site group, issues with analysis or modeling, etc. Excellent/fair/poor: Better rating for fewer biases.
Data Source Diversity of the data used to develop the CMF Excellent: Diversity in States representing different geographies Fair: Limited to one State, but diversity in geography within State (e.g., CA) Poor: Limited to one jurisdiction in one State
Using Filters Search signal (581 results) Filter for only 3,4, or 5 star CMFs (389 results) Filter for only angle crash CMFs (38 results) Filter for only urban CMFs (24 results) Discuss all results, why various categories appear
CMFs that look similar in search results Search for rumble Filter for run off road crash type and crash severities of fatal, serious injury, and minor injury Expand shoulder treatments -> Shoulder rumble strips -> Install shoulder rumble strips What makes the 1stand 2ndones different? Go to Details, see differences in road type and division; AADT range; states of origin
Comparison CMF = 0.64 CMF = 0.83
Comparison CMF = 0.64 CMF = 0.83
Website Features Recently added Reorganized navigation User guide with video tutorials State CMF lists Upcoming Comparison tool
