Final answer:
For 16-year-old drivers in Pennsylvania, Single vehicle/run-off-the-road is the most common type of major crash.
Step-by-step explanation:
The top major crash type for 16-year-old drivers in Pennsylvania is Single vehicle/run-off-the-road accidents. These incidents often occur due to driver inexperience, distractions, or poor handling of the vehicle when in complex driving situations. Young drivers are particularly at risk because they are still developing their driving skills and are more likely to make critical errors on the road.