Problem 2: Gravity Model Application (15) Use the estimates of the future year trip productions and attractions from Problem 1. Compute the inter-zonal trip distribution for the forecast year using gravity model. Be sure to perform the row and column factoring to match the row and column totals of your trip distribution matrix against the predicted productions and attractions. You can stop after two iterations (i.e., one column factoring and one row factoring iteration). Use the following discrete time periods (in minutes) in calibration: {0-5}, {5.1-10}, {10.1-15}, and {15.1-20}. Friction factors are provided in Table 3. Table 4 presents the inter-zonal travel time matrix for the forecast year. Table 3. Calibrated friction factors Time period Friction factor 0-5 0.878 5.1-10 1.752 10.1-15 1.284 15.1-20 0.777 Table 4. Forecast year inter-zonal travel time matrix zone 1 2 3 4 18 15 18 5 18 15 18 5 20 12 12 6 12 10 12 12 20227 222 5 12 10 12 12 68522 12345

Fig: 1