This study explores the driver-ride and road-friendliness characteristics of an urban bus through model derivation and validation, sensitivity analysis, suspension damping optimisation and field assessments. Part I of the study develops a three-dimensional urban bus model by integrating non-linear models of suspension components and tyres that were derived from laboratory-measured data. The vehicle model is validated through field tests, and employed for sensitivity analyses of different operating parameters, including forward speed, tyre inflation pressure, vehicle load and road roughness. The results demonstrate significant roles of these parameters on the dynamic responses relating to driver ride and road-friendliness, which are coupled in a complex manner. The results suggest that measures related to sustainability of urban infrastructure and vehicle structure, together with the health and safety of the drivers, are directly coupled in light of the road roughness. The validated full-vehicle model is further employed for suspension damping design optimisation and its field assessments, which are presented in Part II of the study.