Transit assignment procedures need to reflect the constraints imposed by line routes and timetables. They require specific search algorithms that consider transfers between transit lines with their precise transfer times. Such an assignment procedure is presented for transit networks using a timetable-based search algorithm. In contrast to existing timetable-based search methods employing a shortest-path algorithm, the described procedure constructs connections using branch and bound techniques. This approach significantly reduces computing time, thus facilitating the use of timetable-based assignment for large networks. At the same time, it produces better results in cases where slow but cheap or direct connections compete with fast connections that are more expensive or require transfers.

Several models of route choice in frequency-based assignment are compared for underlying assumptions on service regularity, passenger information, and choice set structure. Numerical results for some simple examples show that route splits differ significantly under different assumptions, so for practical applications the selection of the most suitable choice model is important and none of the models can be regarded as a good approximation for all possible assumptions. Sensitivity of route choice against perturbations of running times or service frequencies is another consideration, because a continuous response improves convergence in demand models with feedback. Finally, it is demonstrated that in terms of expected travel time, the decision about when to alight (and where to continue the journey) is just as important as the decision of which line to board.