What Assumption Was Used by the Authors of the Book

Multiple Choice

What assumption was used by the authors of the book when analyzing the traffic congestion problem in London?

A) They assumed that traffic congestion is the same during daytime and during nighttime.
B) They assumed that every car has the same effect on the travel time of other cars.
C) They assumed that all cars are of the same make and model.
D) They assumed that travel via public transportation is less costly that travel by car.