NTA Appraisal Toolkit | Regional Modelling System

NTA Appraisal Toolkit

The NTA Appraisal Toolkit is an integrated suite of modules for the appraisal of social, safety, health, environmental and economic impacts of transport interventions.

The Appraisal Toolkit consists of 5 modules:

  • Environment Module

Appraisal Toolkit - EnvironmentThe Environmental module calculates emissions based fleet make up and vehicle speed for each road link in the model. Calculations are carried out by ENEVAL using COPERT 5 emission rates.

The Environmental Module outputs emissions by link, zone, sector or grid, which allows results to be mapped in GIS. The emissions estimated include NOx, NO2, PM10, PM2.5, HC, CO, CO2, C6H6, CH4, C4H6.

Figure of annual CO2 Emissions (kg) in the East Regional Model.

Figure: Annual CO2 Emissions (kg) in the ERM

Further detail can be found at the Development report and User guide:


  • Economic Module

    Appraisal Toolkit - Economy

The Economic module calculates the economic costs and benefits of transport interventions.  In essence, it is an Irish version of the UK DfT TUBA (Transport User Benefits Appraisal) program.

Standard outputs of the Economic module:

    • Scheme costs
    • User costs
    • Fuel consumption
    • User benefits and government and operator revenues
    • Benefits by distance and by time saving
    • Transport Economics and Efficiency (TEE) Table
    • Analysis of Monetised Costs and Benefits

Further detail can be found at the Development report and User guide:


  • Health Module

Appraisal Toolkit - HealthThe Health module calculates benefits associated with changes in levels of physical activity and absenteeism as a result of more walking and cycling taking place. The module is based on the relevant UK DfT tool for physical activity assessment. Standard outputs of the Health module:

    • Total Collision Benefits Saved by Scheme
    • Total Collisions avoided by Scheme
    • Total Lives Saved with Scheme

Further detail can be found at the Development report and User guide:


  • Safety Module

Appraisal Toolkit - SafetyThe Safety module uses a bespoke version of the UK DfT COBALT (Cost and Benefit to Accidents – Light Touch) for assessing the impact on accidents (economic appraisal) of a road scheme. Standard outputs of the Safety module:

    • Total Collision Benefits Saved by Scheme
    • Total Collisions avoided by Scheme
    • Total Lives Saved with Scheme

Further detail can be found at the Development report and User guide:

Figure of average annual fatalities by regional model and road.

Validation Test: Annual Road Fatalities


  • Accessibility and Social Inclusion Module

Appraisal Toolkit - Accessibility and SocialThe Accessibility & Social Inclusion (ASI) module assesses the relevant impact of a transport scheme based on travel time, a simple Hansen index, and an income-based geographic indicator. Standard outputs of the ASI module:

    • Travel time benefits
    • Deprivation Index
    • Simple Hansen measure

Figure of walk times for access to Primary Schools in Dublin

Figure: Walk times for access to Primary Schools in Dublin

Further detail can be found at the Development report and User guide: