ICE - Institution of Civil Engineers - Virtual Library

This paper describes the challenges associated with assessing the quality of pedestrian networks and facilities, in particular the diverse nature of pedestrians and their sensitivity to subjective influences. It describes the ways in which those challenges were addressed during development of the pedestrian environment review system (PERS) by the Transport Research Laboratory (TRL). The paper describes PERS and gives examples of its application and use to conduct pedestrian network quality analysis. The benefits and limitations of the approach and lessons learnt in applying pedestrian reviews are discussed in a number of contexts. The paper concludes that the diversity of pedestrian capabilities and purposes in the public realm requires that subjective factors be incorporated into a review system; this, however, poses substantial difficulties for an objective and replicable review system.

The Beddington zero fossil energy development (BedZED) in London, UK, is something of a modern icon in terms of assembling simultaneously on the same site new construction methods, the best of available ‘green’ technology and social engineering combined with new peri-urban lifestyles. The development also includes a number of ‘alternative’ water systems. As with many innovative and exploratory departures, however, not everything went according to plan. This paper describes the bold vision, highlights some of the issues and seeks to learn and disseminate lessons for the future, with special reference to the integrated water and wastewater services.

Groundwater, abstracted from aquifers beneath buildings, can be used as a heat-rejection medium as part of a building cooling system. Such systems have the potential to reduce carbon emissions and provide cost savings, relative to traditional cooling systems that reject heat to air. Three principal configurations of groundwater-source cooling system are used: open-loop systems where the groundwater is discharged to sewer or surface watercourse; open-loop systems where the water is reinjected back into the aquifer; and standing-column boreholes. To date there have been relatively few large-scale applications of groundwater-source cooling systems in the UK. Clear definitions of sustainability targets for such systems do not exist. The current paper identifies characteristics of sustainable groundwater-source cooling systems. A series of tests to determine whether a groundwater-source cooling system can be considered ‘sustainable’ are identified.

In the UK, ballast track beds remain the most commonly constructed, partly because of relatively low initial costs. Concrete track beds, while more expensive to construct, can have lower life-cycle costs and are being actively promoted for use in the UK. This paper describes the results of environmental life-cycle analyses of ballast and generic concrete track beds, including cast-in sleeper and embedded track systems. The scope of the study includes the manufacturing, construction, maintenance, dismantling and recycling of the track bed components. Comparison of the life-cycle analyses of energy consumption and carbon dioxide emissions shows that concrete slab track beds are not associated with higher environmental burdens compared with ballast track bed. The limitations of the available data are also discussed.