3. (7 points total) User and System Equilibrium The following is a simple roadway network with two links. The total vehicular flow between nodes 1 and 2 is 6,500 vehicles/hour (or 6.5 in units of 1,000s of vehicles/hour). Link travel times (ti and t2) are in minutes. X1 t1=6+4x1 12=4+x2² X2 2 a. Assuming the network is in user optimal equilibrium, solve for the number of travelers (X1 and X2). Please use units of 1000s of vehicle per hour. Compute the travel time on each link (ti and t2). (3 points) b. Assuming the network is in system optimal equilibrium solve for the number of travelers (x1 and x2). Again, use units of 1000s of vehicle per hour. Compute the travel time on each link (t₁ and t2). (3 points) c. Briefly discuss the difference between your answers to part (a) and (b). Which of these two equilibrium solutions is more likely to happen on a real roadway network? Briefly explain your answer. (1 point)