Some elements of graduated licencing more effective than others: TIRF

A Traffic Injury Research Foundation (TIRF) report has shown that some specific elements of graduated driver licencing (GDL) programs prove to be more effective at reducing the relative fatality risk than others.
A sound body of evidence documenting the effectiveness of GDL programs in reducing collisions, fatalities and injuries among novice drivers is available. But information about the relative importance of individual components of GDL is lacking, the TIRF report said.
As a result, it is difficult to identify how a GDL program should be best designed or improved.
Researchers examined data from 11 Canadian jurisdictions, 46 American states and the District of Columbia. The timeframe for evaluation was 1992 and 2006, inclusive. Relative fatality risks were calculated for target groups of 16-, 17-, 18-, and 19-year-old drivers and compared to 25- to 54-year-old drivers.
For 17-year-olds, there were no statistically significant findings made.
For 16-year-olds, GDL reduced the relative fatality risk for this cohort by 19.1%, but no such summary effects were found for 17, 18 and 19 year old drivers, the TIRF reported.
For 16-year-old drivers, the restriction on passengers in the intermediate stage of licensing decreased fatality risks, but lifting the passenger limit in the intermediate stage if the passengers were immediate family members actually increased the relative fatality risk of 16-year-old drivers.
One variable was significant with 18-year-olds, TIRF found. Mandatory driver education in the learner stage decreased the relative fatality risk for this age group.
Five variables were significant with 19-year-old-drivers. They include:
•    Length of night restriction in the learner stage (an increase in length of the night restriction in this stage leads to an increase in the relative fatality risk of 19-year-old drivers).
•    Country (Canadian 19-year-old drivers have a higher relative fatality risk than their American counterparts).
•    Lifting night restrictions in the intermediate stage for work purposes increases the relative fatality risk.
•    Exit test in the intermediate stage decreases the relative fatality risk.
•    Mandatory driver education in the intermediate stage showed an increase in the relative fatality risk of 19-year-old drivers.
“In conclusion, despite limitations of the study design, some previously established findings have been confirmed and some interesting and intriguing new findings emerged from these analyses,” the report said.