Two routes connect an origin-destination pair with performance functions t1 = 6 + 4x1 and t2 = 2 + 0.5x2 2 (with t's in minutes and x's in thousands of vehicles per hour). The origin-destination demand is 4000 veh/h at a travel time of 2 minutes, but for each additional minute beyond these 2 minutes, 100 fewer vehicles depart. Determine user equilibrium route flows and total vehicle travel time.