CERC — Environmental Software and Services

Vehicles and roads

Revision to the DMRB Air Quality Screening Method for use in GIS

The Design Manual for Roads and Bridges (DMRB), volume 11, section 3, details a calculation method for estimating the impact that road projects may have on local and regional air quality. This project, in which CERC were working with Atkins for the Highways Agency, involved the development of an updated version of the air quality tool to be used within a new GIS-based version of the DMRB.

By running a number of modelling scenarios using ADMS-Roads, CERC were able to propose a number of improvements to the current DMRB methodology, including accounting for:

DMRB image
  • differing road widths;
  • differing road orientations;
  • variable canyon height; and
  • vehicle-induced turbulence.

In addition, CERC proposed a method that allows the calculations to be performed for road segments, as opposed to roads of infinite length. This was required in order to allow the new implementation of DMRB to be applied within a GIS.

An extensive ADMS-Roads model validation exercise was performed as part of this project, which ran between 2005 and 2006.

Funded by the Highways Agency (sub-contracted by Atkins).

Non-exhaust particulate matter emissions from road traffic[top]

CERC, TRL Limited and the Division of Environmental Health & Risk Management at Birmingham University were commissioned by Defra and the Devolved Administrations (Project CPEA23/SPU82) to investigate non-exhaust emissions of particulate matter (PM) from road traffic. The overall aim of the project was to develop improved prediction methods for emissions and air pollution, primarily for use in the UK National Atmospheric Emissions Inventory (NAEI), based on the existing literature and data.

PM10 mean concentrations

The project was divided into five main tasks:

  • Task 1: A literature review.
  • Task 2: Emission model evaluation, development and application.
  • Task 3: Initial air pollution model development and application.
  • Task 4: Further air pollution model development.
  • Task 5: Discussion of abatement options.

As part of Task 3 of this project, CERC investigated the accuracy of the most up-to-date estimates of non-exhaust particulate (PM10 and PM2.5) emissions by undertaking air dispersion modelling studies at a number of urban sites within the United Kingdom. At these sites, the particulate emissions were modelled using ADMS-Urban, and the predicted pollutant concentrations compared with measured values; comparisons were generally good, in particular for PM10. In terms of source apportionment, the fraction of PM10 concentrations that are due to non-exhaust particulate emissions is almost half of the total traffic source contribution (see figure).

The project ran between 2005 and 2006.

Funded by the Department for the Environment, Food and Rural Affairs, Scottish Executive, Welsh Assembly Government, and the Department of Environment in Northern Ireland.

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The impact of vehicle exhaust location on initial dispersion[top]

Image of a vehicle with a vertical exhaust

In 2005 CERC, working on behalf of DEFRA, compiled data on the exhaust characteristics of cars, LGVs, buses and HGVs.

The exhaust of some makes of HGV may be configured horizontally, or vertically with the exhaust exit above the vehicle (see picture).

In the United Kingdom buses currently use low level horizontal exhaust but one type with vertical elevated exhausts was expected to become available at that time.

Model calculations demonstrated the significant reduction in ground level concentrations that are gained by using vertically orientated exhausts with elevated outlets. Additional conversion of HGVs and buses to such configurations can only increase this effect.

Supported by DEFRA (Department of the Environment, Food and Rural Affairs).

Low Emissions Toolkit[top]

The Low Emissions Toolkit (LET) was developed in 2010-11 by CERC with TTR and RPS for the Low Emission Strategies Partnership. The purpose of the tool is to enable local authority planners and fleet managers to assess the costs and benefits of low emission strategies. The tool quantifies changes in emissions of local pollutants and greenhouse gases, and the associated cost and benefits, due to the introduction of low emission strategies. CERC created the tool as an Excel spreadsheet which performs all the calculations and creates graphical visualisations of the costs and benefits.

Learn more

  • More information and the LET tool itself are available from the LESP website.
  • A presentation on the LET from 2010 (.pdf, <1MB)

TRAMAQ: TRAffic Management and Air Quality[top]

TRAMEC mapper imageTRAMEC picture book image

(Click to enlarge)

As part of the DfT's TRAMAQ research programme, CERC worked with Transport & Travel Research Ltd (TTR) and Millbrook vehicle testing center to develop an emissions calculation software tool for local authorities.

The tool used the latest data on HGV emissions in urban areas under a variety of drive cycles to allow users to take into account the impact of traffic management schemes on vehicle emissions. It calculates emissions of local air quality pollutants and greenhouse gases from road links. TRAMEC has an integrated GIS Mapper and a Picture book from which users selected a drive cycle.

The emissions calculator was piloted with local authorities in the spring of 2004.

Learn more

  • The emissions calculator is available on CD from CERC.
  • TRAMEC user guide (.pdf, 6MB)
  • DfT TRAMAQ website

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