Nomenclature 

P_{n}  Probability of death for pedestrian n 
X_{n}  Independent variable for pedestrian n 
β  Corresponding efficient for variable X_{n} 
K  Number of independent variables 
M  Number of variables and interaction effects 
HL  HosmerLemeshow statistic 
O  Observed accidents of a fatal outcome 
E  Expected accidents of a fatal outcome 
N  Number of observations 
θ_{i}  Predicted risk for the i^{th} risk decile group 