challenge question is c. istanbul is the most congested. mexico city officials have an unusual idea for one way to deal with the terrible congestion rate. the solution isn t to reduce the number of cars on the road by increasing subways and buses. it s a loftier goal. imagine how you would feel is you could soar above all the r cars stopped below. elevated gondolas would allow the citizens to do just that. take a look at the system. as you can see from the model these fit two passengers. they can change direction on the track. in fact, commuters can save time by stopping only at their destination unlike a subway or