High Volume Transport

Vital transport research to ensure accessible, affordable and climate friendly transport for all.

Launch of two key support tools for resilient transport development

Two important decision support tools from the HVT programme launched last week at an event in London and online.

Road Note 31: A Guide to the Structural Design of Surface Roads in Tropical and Sub-tropical Regions from TRL, and Decision Support Systems for Resilient Strategic Transport Networks in low-income countries from Southampton and Oxford universities both offer essential support for road and rail development in low-income countries (LICs.)

Attended in person and online by representatives from the UK Foreign, Commonwealth and Development Office (FCDO), the Department for Transport (DfT), policy makers and practitioners from around the world the session outlined the tools to help ensure transport development in low- and middle-income countries is more efficient, safer and resilient to the impacts of climate change.

Delivering the keynote, FCDO Head of Profession for Infrastructure, Mark Harvey stressed the high cost of road and rail infrastructure and said this is why having the right support mechanisms in place is essential.

“We need resilient transport services to enable development. That’s where we need to focus…And we’ve got to make sure sustainable infrastructure is at the heart of green and sustainable economic growth,” he said.

The updates to Road Note 31 were outlined by John Rolt, lead author of the fourth and fifth editions of RN31, and Andrew Otto, TRL’s team leader on the project.

Since Road Note 31 was first produced in 1962 it has been a valuable resource and formed the basis of many countries’ road manuals. New understandings and advances in road design have seen the need to revise the road notes, with the last update 25 years ago. Today’s road infrastructure faces new challenges, most critically climate change. In this fifth edition of Road Note 31, TRL addresses its effects alongside the latest thinking on road design.

John gave an overview of the advances in road engineering over recent decades. He explained that empirical evidence is key to their studies and some of the new research is quite amazing saying: “Changes are usually small and incremental, occasionally a major change occurs called a paradigm shift. Some of these big changes have occurred in the last 25 years.”

John described a key finding of TRL’s studies in 1986 which challenged accepted assumptions about road failures, most notably that the asphalt surface cracks from the top down rather than the other way around. The cheapest solution to this, John said, was to mill off the top part and replace it, thereby saving millions. Since then, TRL’s research has established revised knowledge of the capacity and longevity of pavements and, crucially, improved awareness and expertise around climate change and how to minimize its adverse effects.

Andrew Otto highlighted ways in which this fifth edition of RN31 has reacted to recent challenges and to the growth in knowledge. It now includes guidance on the design of concrete pavements to help with climate resilience, he said, in addition to road rehabilitation and the use of climate resilient surfacings. Improved designs are in place for rises in temperatures, higher rainfall and extreme storm events. The guide is hosted on a website allowing users to give feedback, which will be gathered and used for further editions.

Key stakeholders spoke at the event highlighting the extensive and crucial use of the Road Note. Dr. Nazmus Sakib from the Islamic University of Technology (UIT), explained how the guide is used in Bangladesh, where climate resistant roads are badly needed. He congratulated the authors on keeping the guide simple, saying it is “Oriented to curious engineers,…and not entirely for academics.”

Richard Humphrey, Team leader and engineer for the Rural Development Programme in Laos, where RN31 is incorporated into the national road design manual, said he eagerly awaits  the 2022 updates, particularly the guidance for climate change adaptation.

Elias Paulo, Director General of the Mozambique National Roads Administration (ANE) said the Road Note is essential not only for road construction but also in universities for training engineers. He said he had himself used it at university and considers it a “very simple tool for road design and construction”.

Following the launch of the fifth edition of Road Note 31, the team from Southampton and Oxford universities introduced their online decision support tool which uses open data to map and model climate impacts.

A number of African countries are witnessing significant large-scale infrastructure investments driven by the prospects of strong economic growth, said Southampton University’s Simon Blainey, Project Lead on Decision Support Systems for Resilient Strategic Transport Networks.  But there is a danger that climate change driven hazards, such as flooding, might be detrimental to their growth and development plans, particularly in the context of widespread failures of transport infrastructures. The aim of the project, he said, was to provide transport decision makers with a set of support tools enabling them to prioritize transport interventions that would deliver sustainable and resilient long distance transport networks in the long term.

Using case study countries Kenya, Tanzania, Uganda and Zambia, the team developed future scenarios for key drivers of transport demand and, from extensive data collected using open street mapping on the infrastructure and its usage within the region, and flood maps from global hydrological models, created the web-based tool which can assess potential losses from flood risk events. These include direct damage costs to infrastructure itself and indirect economic losses incurred as a result of trade disruption.

The work also looks at how to adapt networks to resist events and make them more resilient. A range of indicators was developed – environmental, economic and social – to assist decision makers in assessing the overall sustainability of transport interventions, so giving them the information which allows them to compare the performance of different options.

The SRAT, or sustainability and resilience assessment tool, demonstrated by Tom Russell who led its development, shows the exposure, risk and adaptation of motorway, trunk and primary roads across the case study countries. For any given road in the network, users can use the tool to find the changing risk over time under different climate scenarios.

For planned interventions, it gives a summary across the three pillars of sustainability to assess positive or negative effects. Resilience Analyst Diana Jaramillo presented case studies from Kenya showing how flooding in the future can be identified and interventions put in place.

In answer to questions, the team confirmed that all methods are transferrable to different regions, if data could be collected using the data sets they have created and that different climate change scenarios are available within the tool. Work is ongoing to improve the system, and feedback from low-income countries is welcome.

The tool is available online at https://east-africa.infrastructureresilience.org 

Full reports from both projects are now available including copies of the updated Road Note. [HP3] 

recording of the event is available online on our YouTube channel.

The presentation slide deck is also available here