Two routes connect a suburban area and a city, with route travel times (in minutes) given by the expressions tl = 6 + 8(x1/c1) and t2 = 10 + 3(x2/c2), where the x's are expressed in thousands of vehicles per hour and the c's are the route capacities in thousands of vehicles per hour. Initially, the capacities of routes 1 and 2 are 4000 and 2000 veh/h, respectively.
A reconstruction project on route 1 reduces the capacity to 3000 veh/h, but total traffic demand is unaffected. Observational studies note a 35.28-second increase in average travel time on route 1 and a 68.5% increase in flow on route 2 after reconstruction begins. User equilibrium conditions exist before and during reconstruction.
If both routes are always used, determine equilibrium flows and travel times before and after reconstruction begins.