Keith Vodden Dr. Douglas Smith - Transports Canada

Appendix A—Detail on Calculations of the Ontario Model
For 2004, the model transfers 12 collisions from injury to fatal collisions. These
collisions involve 13 fatalities, 5 major injuries, 25 minor injuries, 16 minimal injuries,
and the following number of vehicles by damage severity: 12 demolished, 3 severe, 3
moderate, 2 light and 1 none.
Similarly the model uses the characteristics of injury collisions 1 to determine the
number and characteristics of collisions to transfer from the revised PDO category to the
injury collision category. However, the correct number of collisions to transfer will vary
depending on which severity category of injury is selected to base the transfer. As a
result, the decision on the maximum number of collisions needed to transfer all injuries is
model determined based on the characteristics of the data. The model transfers injuries in
the proportion they occur in these collisions up to the maximum number by severity
category initially allocated to PDOs. It also transfers the expected number of vehicles
damaged based on this number of collisions. This is illustrated in the next hypothetical
example.
In this example the average injury collision involves 1 injury and 3 vehicles.
Given 10 injuries allocated to PDOs, the model would identify that 10 collision needed to
be transferred involving all 10 injuries and 30 vehicles. (The hypothetical example does
not illustrate that the decision on how many collisions to transfer is based on the number
needed to transfer all injuries of each injury severity.) The 10 collisions are transferred to
injury collisions increasing the total from 100 to 110. Similarly, PDO collisions are
reduced by 10 from 260 to 250. Characteristics of the collisions are also transferred with
offsetting increases for injury collisions and decreases for PDO collisions in the number
of injuries and vehicles involved.
and 0.07 none.
1 Each injury collision includes 0.09 major injury, 0.96 minor injury, 1.02 minimal injury and the following
vehicles by damage level: 0.21 demolished, 0.45 severe, 0.52 moderate, 0.52 light and 0.18 none.
TNS Canadian Facts, Social and Policy Research 125