Evaluation the use of measure of impedance in the passenger-car equivalents for tucks / Avaliação do impacto da medida de desempenho no equivalente veicular de caminhões

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The objective of this research was to evaluate the use of a measure of impedance alternative to density to obtain passenger-car equivalence factors for typical trucks on multilane highways in the state of São Paulo. The impedance investigated was the passenger-car speed, and the equivalence factors were obtained through the average equivalent method since it considers different types of trucks within the traffic flow, is capable to represent interactions among trucks adequately, and allow the use of traffic simulation. Since the estimation method employed is based on a fixed truck population, the truck flow on multilane highways in the state of São Paulo was characterized based on two aspects: (1) a typical traffic flow, considering the traffic flow on typical weekdays, (2) the truck performance based on mass/power ratio. The simulation model employed was CORSIM, the same model used in the HCM-2000, and it was calibrated for the conditions observed in multilane highways in the state of São Paulo. The calibration was carried out using genetic algorithms and involved two steps. The first one focused on the truck motion model and produced average errors around 5%. The second one focused on the car-following logic that defines the driversbehavior. The CORSIM calibrated for the state of São Paulo highways produced average errors of 6.32% at the calibration stage and average errors of 6.58% at the validation stage. Passenger-car equivalents were calculated for different grade levels, grade lengths, trucks percentages, free-flow speeds and leves of service using passenger-car speed and density as the impedance measure. It was observed that, when compared to density, the use of passenger-car speed as a measure of impedance results in higher values for the equivalence factors. It means smaller capacities and worse estimates for level of service.

ASSUNTO(S)

calibração simulação de tráfego calibration genetic algorithm traffic simulation caminhões trucks equivalente veicular algoritmo genético passenger-car equivalent

ACESSO AO ARTIGO

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