The EU has agreed to cut its greenhouse gas (GHG) emissions by at least 80-95% by 2050. Climate policy will require a shift away from petroleum which currently provides nearly all of transport’s energy needs. Apart from a transition towards zero-emission technologies such as battery electric or hydrogen, regulators and governments across Europe are considering what role gas could play in decarbonising transport. This report compiles the latest evidence on the environmental impacts of using gas as a transport fuel.