Traffic operational characteristics at all-way-stop-controlled intersections were investigated by using AWSIM, a microscopic simulation model. The effects of vehicle arrival distribution and traffic volume split on intersection operations were studied. Traffic operations were analyzed from delay, capacity, and queue length perspectives. Empirical models were developed on the basis of simulation results for delay and queue length estimations. It was found that longer delays and queues resulted from platoon arrivals. Higher intersection capacity or lower control delay can be achieved with even volume splits on all the approaches. A generalized form of the delay model showed a better correlation compared with those for exponential-form models used by other studies. A nonlinear relationship was found to exist between the 95th percentile queue length and the average queue length. An empirical model was developed on the basis of the simulation results for estimation of the 95th percentile queue lengths. The model proves to be reliable and easy to use on the basis of field studies, and it fulfills one of the major shortcomings in queue estimation, which is currently unavailable in the "Highway Capacity Manual.".