Garber & Hoel $12-9$: Given a study area with four transportation analysis zones and origindestination survey results, provide a trip distribution calculation using the gravity model for two iterations; assume $K_{ij}=1.$

$\backslash$table$[[,$Travel Time $($min$),,],[$District$,$Productions,Attractions,$1,2,3,4],[1,3400,2800,4,11,15,10],[2,6150,6500,11,6,6,9],[3,3900,2550,15,6,6,11],[4,2800,4400,10,9,11,4]]$

Friction factors are as follows:

$\backslash$table$[[$Time $($min$),4,5,6,7,8,9,10,11,12,13,14,15],[$Friction Factor,$1\mathrm{.}51,1\mathrm{.}39,1\mathrm{.}3,1\mathrm{.}22,1\mathrm{.}13,1\mathrm{.}04,0\mathrm{.}97,0\mathrm{.}92,0\mathrm{.}85,0\mathrm{.}8,0\mathrm{.}75,0\mathrm{.}71]]$