28 Questions
What has enabled safety researchers to extract more information from crash databases?
Steady improvement in statistical methodologies
What is a major barrier despite the progress in statistical methodologies?
Quality and availability of data sources
What is the focus of statistical modelling methods in road safety research?
Assessing the impact of various factors on disaggregate-level injury-severity data
What has improved our understanding of the factors influencing the occurrence of crashes and resulting personal injuries?
Traditional crash data and models
What type of regression model was used to estimate total road traffic deaths?
Negative binomial regression model
How was population used in the regression model for estimating road traffic deaths?
As exposure to interpret the coefficients for independent variables as effects on rates
In the pedestrian crossing behaviour analysis, what was the decision process modelled as?
Discrete choice model
What did the stated preference experiments evaluate in the pedestrian crossing behaviour analysis?
Crossing behaviour in different hypothetical choice scenarios
In the development of pedestrian crossing choice models, what factors significantly affected pedestrian crossing choices?
Road type, traffic flow, and traffic control
What is widely accepted as one of the most important walkability predictors in public spaces?
Perceived safety
What type of model was used to quantify the perception of security in public spaces?
Ordered logit model
In the ordered logit model, what do 𝑈(𝐴𝐵−1) and 𝑉(𝐴𝐵−1) represent?
Utility and systematic portion of utility
What does 𝑅𝑖 represent in the ordered logit model?
Systematically selected alternative
What does 𝜇1 represent in the ordered logit model?
Threshold for the first category
What does 𝜇2 represent in the ordered logit model?
Threshold for the second category
What was the aim of using econometric models to quantify perception of security?
To understand what determines perception of security
What type of regression models address over-dispersion by allowing greater variance than the mean?
Negative binomial regression
What do Poisson regression models estimate the probability of?
A roadway entity having y crashes per time period
What are the injury severities assessed by police officers at the crash scene?
No injury, possible injury, evident injury, disabling injury, fatality
What do crash frequency models aim to determine?
Factors influencing crash frequencies for mitigation strategies
What is used to analyze crashes as the duration of time between incidents?
Duration models
What occurs when the variance of observed accident counts exceeds that expected under a Poisson distribution?
Over-dispersion
What statistical modelling method includes driver behavioral adaptation and risk compensation?
Driver behavioral adaptation and risk compensation are not part of statistical modelling methods
What is used to expand the dataset by linking police data with government-provided roadway information?
Linking police data with government-provided roadway information
Which regression model estimates the probability of a roadway entity having y crashes per time period?
Poisson regression
What aims to determine factors influencing crash frequencies for effective mitigation strategies?
Crash frequency models
Which regression model addresses over-dispersion by allowing greater variance than the mean?
Negative binomial regression
What is the most common source of data extraction in highway-accident studies?
Police crash reports
Study Notes
Statistical Modelling Methods in Accident Severity Analysis
- Most highway-accident studies use police crash reports for data extraction
- Injury severities assessed by police officers at crash scene: no injury, possible injury, evident injury, disabling injury, fatality
- Police-reported data include various factors like time of day, age, road conditions, and crash type
- Inaccuracies associated with police data are well-documented, including underreporting of less severe crashes
- Linking police data with government-provided roadway information can expand the dataset
- Statistical modelling methods include driver behavioral adaptation and risk compensation
- Crash frequency models aim to determine factors influencing crash frequencies for effective mitigation strategies
- Models include Poisson regression, negative binomial, zero-inflated Poisson, gamma, and other specialized models
- Duration models are used to analyze crashes as the duration of time between incidents
- Over-dispersion occurs when variance of observed accident counts exceeds that expected under a Poisson distribution
- Negative binomial regression models address over-dispersion by allowing greater variance than the mean
- Poisson regression models estimate the probability of a roadway entity having y crashes per time period, using explanatory variables
Test your knowledge of statistical modeling methods in accident severity analysis with this quiz. Explore various factors influencing crash frequencies, over-dispersion, and the use of Poisson regression and negative binomial models.
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