Schedule instability adversely affects the performance of bus transport systems. Bus bunching and similar irregularities decrease quality of bus services and increase travel times. In this regard, bus system management schemes are of high importance. Motivated by the potential impact of developing advanced bus control schemes on transportation practice, in this paper a hybrid model predictive control scheme with actuation via bus speeds is developed, which can regularize headways and improve bus service quality. The controller extends upon earlier work by considering detailed dynamics of the interactions between buses and stops via passenger flows. Performance of the controller is compared with a no control case and a PI controller via simulation experiments, conducted with a recently proposed mixed logical dynamical bus loop model involving both continuous (e.g., bus positions) and binary (e.g., the state of a bus regarding whether it is holding at a certain stop or not) states. Results showcase the capability of the proposed controller in regularizing headways, avoiding bus bunching and decreasing passenger travel times.