Are transport policies and economic appraisal aligned in evaluating road externalities?

Noise and greenhouse gas (GHG) emissions are two of the main externalities caused by road transport. At the EU and national levels, many efforts have been implemented to reduce them. Photovoltaic noise barriers (PVNBs) are a technical solution conceived for such a joint objective. This paper presents a method of calculating the efficiency of PVNBs through a cost-benefit analysis by considering current policies and comparing them with the 2010 benchmark scenario. The method was applied to a PVNB located along motorway A22 (Italy). Results show that the component associated with the reduction in transport externalities has been increasing compared with the incentives for electricity production. This outcome corresponds with EU policies but highlights the importance of interpreting results critically, an aspect that policymakers should be aware of in their evaluations