Assessing Driving Behaviour and Empirical Tailpipe Emissions in an Urban Shared Road Section Environment

This paper investigates real-world driving behaviour, vehicle dynamics, and exhaust emissions in urban shared space, addressing critical challenges in road transport in terms of safety and environmental impacts. The case study is one urban avenue in Aveiro (Portugal) composed by one single-lane roundabout, one shared road section, two mini-roundabouts, and three urban sections between mini-roundabouts. Data were collected using three diesel passenger vehicles, with monitoring devices, including an integrated Portable Emissions Monitoring System for emissions measurement, On-Board Diagnostic readers for kinetic variables, global positioning systems loggers, and video recording equipment. The research intends to validate an integrated Driving Indicator (iDI), which was previously developed by the research team, combining safety, volatility, and emissions variables, and comprehensively assesses driving performance. This approach evaluates driver behaviour by considering normal safety-related variables and abnormal driving patterns through acceleration and its first derivative (vehicular jerk) analysis, while simultaneously measuring global (carbon dioxide – CO 2 ) and local (nitrogen oxide – NOx, carbon monoxide – CO, and hydrocarbon – HC) pollutants. The results confirm that roundabout influence areas produced the highest levels of CO 2 , NOx, and vehicular jerk violations, while shared spaces consistently yielded the lowest emission values and driving volatility failures. The validated iDI methodology revealed that emission-related failures dominated across all road types (>60%), followed by safety failures (~30%), with roundabouts recording the highest driving volatility failures.