Abstract
This paper proposes a bus dwell-time model obtained by means of a robust statistical evaluation of boarding passenger data at stops. This model is a change from the generally accepted linear model (i.e., dwell time increases in a fixed rate of time per passenger). The statistical analysis proves the validity of the potential model. This model was derived from a large number of observations on Line 27 of the Transports Municipal Company in Madrid, Spain, and validated with observations from another line (Line 70). The data were gathered by observers who could attest to the influence of occasional incidents in the boarding process. This model can be used to evaluate line capacity more accurately. The analyzed lines were main urban routes with high passenger demand requiring the use of articulated buses. These lines were selected according to two basic criteria: routes with high demand that guarantee good results and routes with similar vehicle types with an onboard payment method. A large proportion of the fares on the two lines comes from monthly passes that require magnetic validation.