Research Highlights Featured Chart

September 4, 2024

Keeping young drivers safe

Targeted nighttime restrictions on teen drivers in Australia

Tyler Smith

Source: zurijeta

Studies have shown that crash risks for teen drivers are higher when they carry peer passengers and drive at nighttime. In Australia, this type of driving resulted in nearly 20 percent of all fatalities  involving first-year drivers. But a policy in the Australian state of New South Wales significantly reduced such risky behavior without keeping teens from gaining experience on the road. Not only that, the policy reduced other types of risky driving and led to ongoing improvements in driving behavior.

In a paper in the American Economic Journal: Economic Policy, authors Timothy J. Moore and Todd Morris found that banning first-year drivers from carrying two or more passengers under the age of 21 between the hours of 11:00 p.m. and 4:59 a.m. decreased the number of crashes and deaths targeted by the policy by more than 50 percent.

The authors linked individual drivers to crash outcomes using administrative data on driver's license records. Then, using a difference-in-differences approach, they compared nighttime crashes to daytime crashes, before and after the policy reform, and estimated the impacts of the restriction on crash rates. 

Panel A of Figure 1 from the authors’ paper shows the crash rates of first-year drivers with two or more passengers between 2004 and 2014.

Panel A of Figure 1 from Moore and Morris (2024)

The chart shows quarterly crashes per 100,000 first-year drivers in New South Wales, between 11:00 p.m. and 4:59 a.m. (black line) on the left y-axis and between 8:00 a.m. and 7:59 p.m. (gray line) on the right y-axis. The dashed vertical line indicates when the nighttime passenger restriction was introduced.

The daytime crash rates are higher than at night because most driving occurs during the day, but both crash rates follow similar trajectories before the restriction is introduced. Immediately after the reforms were introduced in July 2007, there was a drop in nighttime crash rates relative to daytime crash rates. Moreover, the authors find no such daytime–nighttime gap opens up for crash rates with one passenger or none at all, suggesting that the drop in nighttime multipassenger crashes was, in fact, due to the restriction.

The authors find that before the reform, late-night multi-passenger crashes represented 18.3 percent of first-year drivers’ fatalities, but only 4.3 percent afterwards. And overall, the restriction reduced reported multipassenger crashes between 11:00 p.m. and 4:59 a.m. by 57 percent, casualties by 50 percent, and hospitalizations by 58 percent. The authors find that the reform also reduced multi-passenger crashes earlier in the evening and in the second and third years of driving, which together more than doubled the impact of the policy.

The overall effects are similar to estimates of the impact of raising the US minimum driving age by one year. However, the benefits in New South Wales came without delaying young drivers from gaining experience behind the wheel.