Normalized Volume Measurement for Nonmotorized Traffic Flow Mixed with Mopeds

Abstract

Mopeds, experiencing faster growth of use than bicycles, have been swarming urban streets in China in recent years. The mixture of mopeds and bicycles in the same road space has led to great change in the composition and the traffic flow characteristics of nonmotorized traffic. It is impractical to measure the nonmotorized traffic flow by simply aggregating the vehicle counts of mopeds and bicycles because of their distinct temporal–spatial traffic features. This paper proposes a methodology to measure the normalized volume of a nonmotorized traffic mix of mopeds and bicycles. A bicycle equivalent (BE) concept is introduced to measure the moped in equivalent bicycle units and then to normalize the traffic flow mix. Two BE analysis methods that express the relationship between speeds, densities, and occupied spaces for mopeds and bicycles have been developed. A case study estimates the BE from these methods by using field data collected at a midblock section of an arterial in Shanghai. Statistical analysis of observed data shows that the estimated equivalent unit of moped to bicycle is variable under different traffic conditions. Specifically, the equivalent value of moped to bicycle is less than one under lower-density conditions. The value is, however, more than one under higher-density conditions. These findings are valuable to support the measurement of a nonmotorized traffic mix of mopeds and bicycles.