The UK Department for Transport (DfT) has published an update to its Transport Appraisal and Strategic Modelling (TASM) research reports collection, strengthening the evidence base that underpins transport appraisal, strategic modelling and policy-making across the country. The comprehensive repository of research, analysis and technical guidance was last updated on 29 January 2026 with a new technical note on Estimating carbon emissions from road users.

TASM research supports robust, evidence-based decision-making by government transport planners and practitioners, ensuring that investment decisions reflect economic, social and environmental impacts of transport interventions. The collection brings together studies spanning core appraisal methods, economic growth effects, emissions analysis, forecasting future travel demand, and the valuation of investment impacts.

New and updated reports

Among the most recent additions to the TASM collection is a technical note on estimating carbon emissions from road users, published under the Environment and Health theme, aimed at improving the accuracy of emissions modelling used in appraisal frameworks such as WebTAG and the National Transport Model.

Other notable reports - added across late 2025 and 2024 - cover a broad range of critical appraisal topics, including:

• Transport appraisal and cost damping and distributional impact appraisal audit, enhancing the tools available to assess cost behaviours and social impacts.
• Research into wider economic impacts and agglomeration benefits, enriching understanding of how transport infrastructure influences productivity and spatial economic relationships.
• Reports on transport investment and unemployment as well as multi-modal appraisal methodology, contributing evidence on labour market effects and integrated appraisal approaches.

For transport professionals, planners and analysts, the updated TASM repository provides refreshed evidence and methodologies to support scheme development, appraisal reporting and business case preparation. By integrating insights from the latest research, practitioners can ensure that technical assessments reflect evolving policy priorities - including net-zero commitments, inclusive economic growth and resilient infrastructure planning.

A list of all the policy reports and technical papers CIHT has produced in the last 10 years can be found at Directory of Policy Papers and Reports | CIHT