Final answer:
Fatal single-vehicle rollovers have reduced due to technological advancements in vehicle safety such as crumple zones and plastic components that absorb collision impact, improving protection for passengers and reducing force during collisions.
Step-by-step explanation:
Fatal single-vehicle rollovers have become less frequent due to a combination of factors such as improved vehicle technology, increased safety regulations, and enhanced driver education. For example, modern cars are designed with crumple zones which help protect passengers by increasing the time of impact during a collision, effectively reducing the force exerted on occupants (Answer: a), as this technology absorbs energy from the impact.
Furthermore, advancements in automotive engineering have led to increased use of plastic components in cars, contributing to both better gas mileage and safer collision outcomes. Cars are engineered to crumple in a way that lengthens the collision time, thereby lessening the force on the car's occupants. These improvements have led to a marked reduction in fatalities during various forms of motorsport, where the adoption of vehicles that can absorb the energy of a collision has had a dramatic impact on driver safety.