“our” version of the gravity model

Gravity Model Application Process Note: little boxes like these (on subsequent pages) will help you keep track of where you are in the process

Homework (refresh from 355)

Step 3: Look Up Friction Factors Based on the total travel times you calculates in Step 2, fill in the HBW friction factors for Zone 5 in the friction factor matrix, using the Friction Factor Look-up Table provided on the next page.

Note: on the following page, trip distribution from zone 1 is done for you. You are to calculate distribution from zone 5

From zone 1 From zones 2-4 From zone 5

Step 5: Adjust Input Attractions Fill in the last line in the table on the next page as follows:

Step 6: Perform 2nd Iteration Repeat the calculation steps you did in Part 3 in the table on the next page. Note that productions are all the same as in part 3, but the attractions have been changed based on our calculations on the previous page. Hint: some values filled out on the next page provide “checks” of your work on the previous page.

From zone 1 From zones 2-4 From zone 5

Don’t forget!