Would personal carbon trading reduce travel emissions more effectively than a carbon tax?

Behavioural effects of a tradable driving credit scheme: Results of an online stated adaptation experiment in the Netherlands

“…Unfortunately, although both studies included travel-related carbon savings in the presented choice options, the relative impact of car use-specific options remains unclear from these studies. Raux et al (2015), studying a PCT scheme for car travel only, designed a stated preference experiment that included trade-offs on various suggested reduction levels, which were presented as a proportion of annual number of trips for different distance categories based on reported travel habits. With regard to duration, they found a higher willingness to reduce the number of shorter trips and, with regard to purpose, of commute and shopping trips.…”

“…Raux et al (2015) empirically investigated the effects of a personal carbon trading scheme on travel behaviour alone, whereas Zanni et al (2013), Parag et al (2011) and Capstick and Lewis (2010) studied the effects of such a scheme on all energy consuming actions of individual households. Kockelman and Kalmanje (2005) explored drivers' reactions to a credit-based congestion pricing policy, in which credits were not formally tradable in a market but could be exchanged for money.…”

“…However, these studies have generally investigated responses either in fictitious decision contexts or at a highly aggregated level. That is, they either elicited responses to scenarios that were based on hypothetical, non-experienced trips (e.g., Kockelman and Kalmanje, 2005) or presented options to respondents in which they could change their annual mileage or number of trips without a clear and direct connection to concrete activities and trips (e.g., Raux et al, 2015;Zanni et al, 2013;Parag et al, 2011;Capstick and Lewis, 2010). We argue, however, that placing TDC responses in the context of people's daily activity patterns leads to a more reliable understanding of TDC decision-making as a trade-off between credit availability and real activity and travel needs.…”

Tradable credits for managing car travel: a review of empirical research and relevant behavioural approaches

“…First, with regard to measuring behavioural change, the present set of studies on individual TC responses represents a very diverse body when it comes to the unit of analysis: annual carbon consumption/distance/number of trips (Capstick & Lewis, 2010;Parag et al, 2011;Raux et al, 2015a;Zanni et al, 2013), set of activities/trips (Aziz et al, 2015;Harwatt et al, 2011;Kockelman & Kalmanje, 2005) or a single trip (Raux et al, 2015b). Unfortunately, studies that measure individual TC effects using a fictitious base situation (e.g.…”

“…In comparing the level of change in car travel behaviour under a PCT and a carbon tax scheme, Raux et al (2015a) presented participants with personalised trade-offs in which the level of car travel reduction that could be chosen, tax/credit price per litre of gasoline and size of the free allowance (specified in litres of gasoline, applied to both PCT and carbon tax) varied. After participants' travel habits had been recorded during interviews, their car trips for a full year were categorised based on distance, and options for car travel reductions were defined as a percentage of the number of trips in these distance categories.…”