Final answer:
The lane used to gain speed before merging onto a highway is known as the acceleration lane, which enables safe and smooth traffic integration.
Step-by-step explanation:
The lane going onto a highway used for picking up speed is called an acceleration lane. This lane allows drivers to increase their speed to match that of the vehicles on the highway before merging into traffic. It is important for safety and traffic flow that drivers use the acceleration lane to gain enough speed so they can integrate smoothly with the vehicles on the highway without causing disruptions or posing a risk of accidents.