When is it legal to drive in a carpool lane?

Answer: B — When vehicle is occupied by at least 2 people

Driving in a carpool lane is only legal when the vehicle is occupied by at least 2 people. This lane is specifically designated for vehicles with multiple occupants to help reduce congestion and improve traffic flow. Option A is incorrect because while some carpool lanes may require a minimum of 3 people, there are also carpool lanes that only require 2 occupants. Option C is incorrect because while carpool lanes may have designated rush hour times, it is not legal to drive in them at all times during rush hour. Option D is incorrect because the minimum number of occupants for a carpool lane is typically no more than 3 people.