International research conducted in 2018 involving: (a) an online survey conducted to assess public responses and the role of public authorities to a voluntary emission standard for passenger cars, and (b) two online experiments conducted to test incentives in the design of ecolabels (e.g. price, safety, performance) for optimization. A random sample of 6400 individuals from across eight countries (Germany, Ireland, Italy, the Netherlands, Spain, UK, Czech Republic and Lithuania) were involved in the study. Whilst the results suggest that Europeans are aware of the health and environmental impact of cars, the findings also confirm the gap between self-reported attitudes/intentions and actual behaviours. In influencing car purchase decisions, health and environmental concerns are less important than other attributes such as price, safety and performance. Similarly, it is argued that respondents are more likely to choose European Union Low Emitting carS (EULES)-friendly cars when the label shows information on lower costs or lower taxes and less likely to be influenced by health-related benefits, convenient parking or access fees.