Final answer:
The time required to get a vehicle up to speed for safe merging on an interstate is influenced by the length of the on-ramp, the weight of the load, and the ramp's curvature.
Step-by-step explanation:
The factors that determine how much time is needed to get your vehicle up to speed to safely merge with oncoming traffic on an interstate are indeed D. All of the above. Specifically, they include A. the length of the on-ramp, as a longer on-ramp provides more distance to accelerate; B. the weight of your load, since heavier vehicles require more time to accelerate; and C. the on-ramp's degree of turn, because sharper turns can limit your acceleration capability. For instance, consider a scenario where a car merges into freeway traffic on a 200-m-long ramp with an initial velocity of 10.0 m/s and an acceleration of 2.00 m/s²; calculating how long it takes to travel up the ramp offers useful insights for traffic engineers.