How does unsustainable urbanization affect driving behavior and vehicular emissions? Evidence from Iran

Poor urban development and social instability are the results of unsustainable urbanization. These urban risks could significantly influence public culture and might even lead to aggressive driving styles. A practical approach comprising of model estimation and real-world measurements is applied here to discuss the role of urban development and public culture in the driving behavior and vehicle emissions in an unsustainable urbanized city, i.e. Isfahan, Iran. Over 60,000 speed-time data were collected from the streets for several time slices to develop the ISFahan Driving Cycle (ISFDC). ISFDC is assessed against the DCs of foreign countries and other Iranian cities to discuss the contribution of the studied factors to driving behavior. ISFDC is then entered into the IVE model to estimate the exhaust emission factors (EFs) under real-urban conditions, while IVE is primarily adjusted to the real-world experiments. Also, several emission mitigation scenarios that are likely to mitigate vehicular emissions are evaluated. Results show that ISFDC is already unique around the world, but unsustainable urbanization in terms of poor urban development and aggressive actions/reactions plays a vital role in the driving behavior of Iranian drivers. Unsustainable urbanization causes the CO and NO_x EFs of Isfahan vehicles to be 40 and 25.47 % higher than those in Tehran, and 60 and 57 % higher than those in Beijing, respectively. Among the studied EFs, CO EF is more affected by the level of urban development. Ammonia, Formaldehydes, and Benzene are consecutively ranked as the major toxic gases in the Isfahan vehicle exhausts.