Sorry to keep asking for this. I'm going to look at it soon, I just don't want to spend a lot of time getting into it.
By more simple, I mean, does it have to have 4 makes, 6 trucks, 2 transports (would it break with 1).
Does changing a truck's model break it or only changing makes?
If the error only happens when updateObservable is called, can you remove addTruck / addVehicle.
Is trucksCtrl necessary, or can you just render like:
$("#trucks").element.html(can.view('t-trucks', {trucks: trucks}));
Is
if (showData)
$("#data-makes").html(htmlData(makes));
necessary?