To download a free online PDF copy of Road Note 31 (5th Edition), please use the link on this page to access the latest edition (updated Nov 2024).
For more information about the project to revise RN 31 and links to more material about, please visit the RN 31 project web page.
If you have any questions about RN 31 or are interested in either the creation of an annex for your country or even specific Manuals in general, please contact TRL.
The spreadsheets referenced in RN 31 can be downloaded directly here.
Pavement Design Spreadsheet (Oct 2025)
This spreadsheet is used for the undertaking both flexible and rigid pavement designs based on the pavement options and materials presented in RN 31. Two methods of design traffic estimation are presented before undertaking the design, the method based on individual axles, and another based on axle groups. The spreadsheet is design to allow the user to control most inputs. It is recommended that it is used by experienced pavement design engineers.
Bituminous Surfacing - Initial Deterioration Diagnosis Tool
This spreadsheet is based on RN 18, now integrated into RN 31. It serves as initial diagnostic tool for determining the most like causes of defects observed in flexible pavements. After initial diagnosis is done, a detailed investigation and rehabilitation design is necessary.
Flexible Pavement Catalogue Design Examples with Overlay Design (Sept 2024)
This spreadsheet provides worked examples of flexible pavement overlay design based on the structural number method, and the RN 31 structural number and deflection method.
Pavement Design Options Carbon Comparison Tool V4
This spreadsheet is used for the comparison and selection of the most optimal design option from the pavement options and materials presented in RN 31. It has an embodied carbon (GHG) emissions calculator, a cost calculator, and a resilience scoring tool. The spreadsheet enables the selection of the most optimal design option based on the following criteria: initial costs, reseal/overlay/inlay costs, the net present value (NPV), economic internal rate of return (EIRR), greenhouse gas emissions (GHG), climate resilience score, and environmental social impact assessment (ESIA).
If you have trouble downloading or using the spreadsheets please contact TRL.
Whilst efforts have been made to ensure the accuracy of the information contained in this spreadsheet, the content is subject to change and TRL Limited, UK Foreign, Commonwealth, Foreign and Development Office (FCDO), and DT Global and their affiliated organisations cannot guarantee its accuracy or currency. The right is reserved to make changes to the contents without notice. TRL Limited, UK Foreign, Commonwealth, Foreign and Development Office (FCDO), and DT Global and their affiliated organisations do not accept any liability for any direct, indirect, incidental, or consequential losses arising from the use of these tools. By using these tools, you are deemed to have consented to these conditions.
