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To investigate the conformity of the 'urban streets' part of ETC cycle to the real-world driving cycle of heavy duty city buses, a test of bus city driving is conducted on 2 typical LPG city buses running on 2 typical routes in Guangzhou City with vehicle speed and gear position measured for each second. Based on these data the corresponding speed and torque of engine are then calculated and compared with that in the urban part of ETC cycle. The results show that compared with the ETC cycle, the time proportion of idling in real-world driving is 1.4 times higher, and 0. 8 times higher for zero-torque mode, 38.34% lower in average speed, and 59.09% lower in average torque. In speed distribution the real-time driving mode is mainly concentrated at low speed range while the ETC cycle is basically at medium and high speed regions. As for torque distribution the real-time driving mode is mainly concentrated at tow torque region while the ETC cycle is rather widely spread over the whole torque range, so there is a significant difference between the real-world driving mode of LPG city buses and the urban part of ETC cycle. [ABSTRACT FROM AUTHOR]