Table 2.
Estimated percentage of reduction in mean proportion of 16- and 17-year-old driversa involved in fatal crashes attributed to the adoption of GDL laws alone, and to GDL laws in the presence of selected covariates.
| Effect measured | % change with “Any” GDL law | % change with only “Good” GDL law | ||
|---|---|---|---|---|
| Calculation 1c | Calculation 2d | Calculation 1c | Calculation 2d | |
| GDL law alone | 10.2 | 27.6 | 9.9 | 27.3 |
| GDL law with all covariates | 6.8 | 24.8 | 9.0 | 26.6 |
| GDL law with primary seat belt law (SB)b | 7.7 | 25.5 | 7.7 | 25.5 |
| GDL law with zero tolerance law (ZT)b | 11.1 | 28.3 | 12.7 | 29.6 |
| GDL law with .08 BAC limit law (.08)b | 7.6 | 25.4 | 8.4 | 26.1 |
| GDL law with use & lose lawb | 9.3 | 26.8 | 8.4 | 26.1 |
Age ratio used for estimate: 16–17/21–25.
SB=states with primary enforcement seat belt laws; ZT=states with laws for zero tolerance of any alcohol for drivers <21 years in which drivers’ license is forfeited; .08=states with a blood alcohol concentration legal limit of .08 g/dL for all drivers; Use & Lose=states with laws in which persons <21 years caught with alcohol in any situation lose their driver’s license.
Calculation performed assuming no change in ratio denominator (16–17/21–25) pre- and post-passage of GDL laws.
Calculation performed using actual change in ratio denominator (16–17/21–25) pre- and post-passage of GDL laws.