Motorcycle driving cycle and emission characteristics in urban and rural complex metropolitan

• Yunlin Motorcycle Driving Cycle (YMDC) reflects rural driving with high speed • YMDC emission and fuel consumption more accurately represent real-world driving • Analysis shows lower CO/NOx but higher HC and fuel consumption • Phase IV releases more VOCs and olefins, indicating incomplete combustion To quantify motorcycle emissions under realistic operating conditions, this study reproduces on-road riding behavior rather than relying solely on certification driving cycles. A localized real-world motorcycle driving cycle was developed for Yunlin City, where riding behavior is characterized by lower traffic density and frequent transient operations. Compared with the urban segment of the World Motorcycle Test Cycle (WMTC), the temporal shares of acceleration, cruising, and deceleration observed in Yunlin differed substantially, reflecting local traffic conditions, although the overall distributions of idling, acceleration, cruising, and deceleration were broadly comparable. Exhaust emissions were measured from two motorcycles representing different regulatory phases. Under identical real-world operating conditions, the phase VII motorcycle exhibited mean exhaust concentrations of 0.39% CO, 14.04% CO₂, 23.82 ppm HC, and 64.91 ppm NOₓ, with a fuel consumption of 0.037 L·km⁻¹. In contrast, the phase IV motorcycle showed markedly higher pollutant levels—6.24% CO, 10.85% CO₂, 398.06 ppm HC, and 213.03 ppm NOₓ—and greater fuel use at 0.103 L·km⁻¹. On average, emissions from the phase IV motorcycle were 15.9 times higher for CO, 16.7 times for HC, and 3.28 times for NOₓ, while fuel consumption was 2.79 times higher and CO₂ emissions were 0.77 times lower than those of the phase VII motorcycle. These results demonstrate that emission estimates derived from certification cycles may underestimate real-world motorcycle emissions, particularly for older vehicles. Incorporating localized driving behavior, such as that captured by the Yunlin Motorcycle Driving Cycle, is therefore essential for accurately characterizing in-use emissions and supporting effective emission assessment and regulatory planning in mixed urban–rural regions.