For Gravity model, the number of trips made between two zones is typically

$($directly$/$inversely$)$ proportional to the travel time between the zones

In the equation for the Gravity model discussed in class, larger is the travel time between two zones i and j$,$

$($larger$/$smaller$)$ is the value of F subscript i j end subscript between the zones.

A transportation planning agency developed a gravity model for trip distribution ensuring that the sum of rows equals the production total and the sum of columns equals the attraction total. This is called a

$($singly$-$constrained OR doubly$-$constrained$)$ gravity model.

For mode choice models, as the utility of a mode decreases, the proportion of travelers choosing that mode

$($increases$/$decreases$).$