Within the lifetime of present and planned Highways Agency (HA) assets significant changes are expected in UK climate. The HA is required to minimise the risk climate change poses to the strategic road network and has begun a programme of research aimed at understanding the impacts of climate change and planning revisions to Standards Specifications and Operating Procedures. Priorities for further investigation were identified and more detailed investigation has been undertaken into the impact of changes in extreme temperature and precipitation. The analysis of historical data illustrates the possibility of a small increasing trend in extreme daily maximum temperature, in some regions, although any difference in extremes is within the range of standard error. Our analysis of climate model simulations, however, highlights the possibility of much larger changes in extreme temperature during the lifetime of present and planned HA structures. Therefore, existing design standards are likely to be adequate for the present day, but revisions should be considered due to the scale of changes that are possible during the lifetime of new structures. The analysis of extreme precipitation illustrates that the 20% contingency presently applied may be adequate for 1 and 5 year return period storms even up to the 2080s for a high emissions scenario, but uncertainties in climate model projections should be further assessed. For the covering abstract see ITRD E139491.
Samenvatting