The improvement and maintenance of non-national roads in its area is a statutory function of each individual road authority. The choice of final surfacing type to be used on such roads is a matter for each road authority having regard to a number of factors, including location, subsoil conditions, existing pavement construction, type and volume of traffic and relative costs of surfacing materials.
My Department has issued no advice to road authorities on the proportional split they should adopt between surface dressing and other forms of final surfacing on non-national roads. To assist the authorities, however, my Department issued a guidance document in 1999, Guidelines on the Depth of Overlay to be Used on Rural Non-National Roads. This document advised: "Surface dressing should be applied to dense bitumen macadam overlays as soon as is practicable for skid resistance purposes". This requirement has been included in circulars issued by my Department since 2001, most recently in Circular RLS 21/2005 of 14 June 2005.
In the absence of detailed information on subsoil conditions, traffic volumes, etc. on all parts of the non-national road network, it is not possible to determine if the adoption of any particular type of road surfacing would result in savings in whole-life road maintenance costs. My Department has no function in regard to national roads. Responsibility for national roads is a matter for the relevant road authority and the National Roads Authority, which operates under the aegis of my colleague, the Minister for Transport.