Keith Vodden Dr. Douglas Smith - Transports Canada

Appendix A—Detail on Calculations of the Ontario Model
5. Tow trucks
Tow truck services are required when either or both the vehicle cannot be driven
safely or no licensed individual is able to drive the vehicle from the collision scene. Data
from Transport Canada’s former Passenger Car Survey (PCS, data used by the study are
from 1984 to 1989) indicate that 89% of the vehicles involved in fatal collisions were
towed and 57% of those involved in injury collisions required the services of a tow truck.
We assume that 40% of vehicles involved in PDO collisions (not included in the survey
coverage) were towed. Thus, the number of vehicles in each type of collision that were
towed is derived by applying these proportions to the total number of vehicles involved in
collisions including those that were not damaged (in keeping with the survey coverage).
As a check on the correct proportion to use, the per cent of vehicles that are demolished
or have severe or moderate damage is 86%, 63% and 46% for fatal, injury and PDO
collisions respectively. The percentages identified from the PCS and by extrapolation
approximate these percentages based on vehicle damage with slightly higher percentages
for fatal collisions and lower percentages as collision severity declines. This is in keeping
with our expectations that more vehicles will be towed for reasons other than vehicle
damage as collision severity increases. Our costing methodology deducts estimated costs
for tow truck services from insurance payments calculated elsewhere. As a result any
error in our estimate of tow truck costs will be countered by an off-setting error in the
value of remaining items paid for through insurance claims.
Exhibit A-16 provides the estimated number of vehicles requiring tow truck
services in 2004.
Exhibit A-16
Tow truck services
Collision Severity
Fatal Injury PDO TOTAL
Vehicles damaged:
Demolished 723 13,150 4,107 17,980
Severe 200 27,605 30,903 58,708
Moderate 157 32,436 105,753 138,345
Light 133 32,158 148,879 181,170
None 48 11,258 19,443 30,748
Total 1,261 116,606 309,084 426,951
Per cent requiring tow 89% 57% 40%
Total requiring a tow 1,122 66,465 123,634 191,221
TNS Canadian Facts, Social and Policy Research 137