Policy-makers and planners concerned with sustainable transport systems have continuously advocated the use of alternative fuel vehicles as a means of reducing road vehicle emissions. The environmental benefits of one such type of alternatively fuelled vehicle, natural gas vehicles (NGVs), are well-documented. Despite the much-proclaimed environmental benefits of NGVs however, there has been little take-up of these vehicles in the UK. A review of current policies towards these vehicles and the ways in which they are promoted may therefore be necessary to encourage their market penetration. A stated preference survey was conducted among freight transport operators throughout the UK, which revealed that economic factors, namely vehicle capital costs and (fuel) operating costs, and fuel availability were of most importance to operators when considering the purchase of a new vehicle. Consequently, policies that not only make NGVs financially competitive but in fact also give them a financial advantage over conventional vehicles, complemented by measures to increase the supply of fuel, may prove most effective in encouraging the adoption of these vehicles among UK road freight operators. Obviously, the operators must be aware of these improvements and, as such, these policies must also be supported by a vigorous promotional and awareness campaign.