Traffic Impact Assessment
What is this assessment?
The Traffic Impact Assessment evaluates the potential traffic and transport implications of proposed developments. They assess the sustainability of developments and ensure compliance with transport policies. They can be standalone reports or part of an Environmental Impact Statement (EIS).
Legal basis: Planning and Development Act 2000 / Road Traffic Act 1994.
What is the process?
Scoping and initial planning
Determine if a TIA is required based on the development size, type, and location. This may involve consulting Transport Infrastructure Ireland (TII) guidelines or local authority requirements.
Then, conduct a scoping study with relevant authorities (e.g. local roads engineer, planning department) to agree on the assessment criteria and content.
Data collection and analysis
Gather existing data on the current road network, including:
- Traffic volumes
- Collision history
- Road capacity
- Existing developments in the area
Conduct necessary surveys, such as:
- Traffic counts
- Parking surveys
- Topographical surveys
Finally, analyse the collected data to establish baseline conditions.
Development impact assessment
- Estimate trip generation rates for the proposed development
- Predict traffic volumes and routing on the transport network due to the development
- Analyse the capacity of the transport network to accommodate the additional trips
Modelling and analysis
- Use specialised traffic modelling software to assess key junctions and road sections
- Project future traffic volumes using growth rates for future years
- Evaluate the performance of the road network with and without the proposed development
Mitigation and alternatives
Propose mitigation measures where necessary, such as:
- Junction upgrades
- Traffic management plans
- Parking improvements
Then, consider alternative transport modes / sustainability measures and perform a cost-benefit analysis for proposed mitigation measures.
Reporting and submission
Prepare a comprehensive TIA/TTA report including:
- Description of existing conditions
- Development details
- Traffic generation estimates
- Impact analysis results
- Proposed mitigation measures
- Compliance with relevant policies and standards
Submit the report to the relevant planning authority as part of the planning application.
Review and iteration
Address any requests for further information from the planning authority. Revise the assessment if necessary based on feedback or changes to the development proposal.
This process ensures a thorough evaluation of the traffic and transport impacts of proposed developments in Ireland. It helps to maintain sustainable and efficient transportation systems.
Plans are developed to address any identified adverse impacts. These measures aim to enhance traffic flow and safety while ensuring that the development is sustainable.
Submitting your assessment
The results of this assessment should be included with your submission to the relevant planning authority.