FIGURE 1 Spatial Distribution of Expected Motor Vehicle Crash Frequency for Total Crash Counts and Counts by Severity Levels TABLE 1 Summary of Existing Multivariate Crash Frequency Studies Number of Studies Unit (Scale) Methodology Dependent Variables Analyzed Dimensions Examined Crash frequencies by severity level - property Multilane freeway segment Joint Poisson regression (Ye 2013) damage only, possible 3 et al. model injury, and injury/fatality Full Bayes multivariate Poisson frequencies by severity level - Fatalities, (Aguero-Valverde State-maintained rural lognormal major injuries, moderate injuries, minor injuries, 5 and Jovanis 2009) roads (Micro) models and PDO Crash frequencies by severity level slight injury, – Single carriageway link Bayesian Multivariate (Tunaru 2002) serious/fatal injury by number of vehicles involved 4 sites (Micro) Normal (1 and 2+) (Ladron de Guevara Traffic analysis zone Simultaneous negative binomial Crash frequencies by severity level no injury, – 3 2004) (Macro) model injury and fatal et al. frequencies by location intersection crash, – Bayesian multivariate (Song 2006) District intersection-related crash, driveway-access crash, 4 et al. conditional autoregressive model and non-intersection crash
FIGURE 1 Spatial Distribution of Expected Motor Vehicle Crash Frequency for Total Crash Counts and Counts by Severity Levels TABLE 1 Summary of Existing Multivariate Crash Frequency Studies Studies Unit (Scale) Methodology Dependent Variables Analyzed Number of Dimensions Examined (Ye et al. 2013) Multilane freeway segment Joint Poisson regression model Crash frequencies by severity level - property damage only, possible injury, and injury/fatality 3 (Aguero-Valverde and Jovanis 2009) State-maintained rural roads (Micro) Full Bayes multivariate Poisson lognormal models frequencies by severity level - Fatalities, major injuries, moderate injuries, minor injuries, and PDO 5 (Tunaru 2002) Single carriageway link sites (Micro) Bayesian Multivariate Normal Crash frequencies by severity level – slight injury, serious/fatal injury by number of vehicles involved (1 and 2+) 4 (Ladron de Guevara et al. 2004) Traffic analysis zone (Macro) Simultaneous negative binomial model Crash frequencies by severity level – no injury, injury and fatal 3 (Song et al. 2006) District Bayesian multivariate conditional autoregressive model frequencies by location – intersection crash, intersection-related crash, driveway-access crash, and non-intersection crash 4
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