Final answer:
To enter an interstate highway, use the ramp or entrance ramp until your vehicle's speed matches that of highway traffic and then merge safely.
Step-by-step explanation:
To enter an interstate highway, use the ramp or entrance ramp until your vehicle's speed matches that of highway traffic and then merge safely. The ramp provides a controlled and gradual transition from a lower speed road to the higher speed of the highway. It allows the driver to adjust their speed and find a suitable gap in the traffic before merging.