Low-traffic roads may not attract the same attention as motorways and major national routes, but they make up a substantial part of Norway’s road network. Keeping them in good condition is a challenge for county authorities, particularly when maintenance budgets are tight.
Two PhD candidates at NTNU are now approaching this challenge from different angles. Beza Taye is studying rehabilitation methods and their effectiveness, while Zaki Alzaki is investigating how the condition and deterioration of low-traffic roads can be better mapped and understood.
Both are part of the SINTEF-led research project Rehabilitering av lavtrafikkerte veger (Rehabilitation of low-traffic roads), which runs from 2024 to 2028 and brings together SINTEF, NTNU and 14 Norwegian counties.
From Ethiopian roads to Norwegian conditions
Beza Taye is originally from Ethiopia and started her PhD at NTNU in 2026. She brings more than nine years of experience from the Ethiopian Roads Authority, where she worked with road construction and maintenance.
Her academic background also fits closely with her new research. Her master’s research focused on pavement materials, particularly asphalt and asphalt mixtures. For Taye, the combination of practical experience and materials knowledge provides a useful starting point for studying Norwegian roads.
“From my work in Ethiopia, I have seen the practical challenges involved in maintaining roads. Combined with my background in pavement materials, this made rehabilitation of low-traffic roads a very natural research topic for me,” says Taye.
Her PhD focuses on four closely connected questions: Why do low-traffic roads deteriorate? How do Norwegian counties rehabilitate them today? How well do the different methods actually perform? And how can this knowledge help road owners choose the right rehabilitation measure for a particular road?
The last question is particularly important. Rehabilitation decisions have traditionally relied heavily on experience and local knowledge. Taye wants to investigate how existing road-condition data and measurements can provide a stronger basis for such decisions.
“The goal is to connect the cause of deterioration with the rehabilitation method and its actual performance. If we understand those relationships better, road owners can make more informed decisions about which measures to use and where,” she says.
Following real rehabilitation projects
The research does not stop at models and laboratory work. Taye is following rehabilitation projects on county roads in different parts of Norway. So far, her research encompasses six road rehabilitation projects. Three were carried out in 2026, one is planned for 2027, while two were rehabilitated in 2020 and are being monitored to see how they perform over time.
The projects use different rehabilitation measures, giving Taye the opportunity to compare their performance under real conditions. Her research combines fieldwork and condition surveys with sampling, on-site testing and laboratory analysis of road materials.
By studying roads both before and after rehabilitation, she hopes to identify which approaches provide the most durable results under different conditions.
“There is no single rehabilitation method that will be right for every road. We need to understand the condition of the road, what is causing the deterioration and how different treatments perform over time,” says Taye.
Ultimately, the ambition is to develop a decision framework that county road owners can use when choosing rehabilitation measures.
Mapping why roads deteriorate
While Taye concentrates on rehabilitation methods, Zaki Alzaki approaches the challenge from the condition-data side.
Alzaki is originally from Syria. He earned a bachelor’s degree in water engineering from Al-Furat University in 2013 and subsequently worked as a teaching assistant there. After moving to Sweden in 2015 because of the civil war, he spent ten years in Halmstad.
During his time in Sweden, Alzaki gained experience from both industry and academia. He worked for seven years as a project engineer at Trafikverket, the Swedish Transport Administration, and completed a master’s degree in infrastructure and environment at Chalmers University of Technology from 2022 to 2024.
He has now moved to Trondheim with his family to pursue a PhD in pavement technology at NTNU.
“I have always enjoyed the academic side of engineering, especially research and the university environment. My experience from Trafikverket also gave me practical insight into road projects, and the PhD gives me an opportunity to bring those two sides together,” says Alzaki.
His research focuses on condition mapping and the development of low-traffic county roads. A key task is to identify the factors and mechanisms that cause deterioration and understand how they influence road condition over time.
Making better use of road data
One important resource is NVDB, the Norwegian Road Database, together with other available databases and information from the counties. Alzaki will analyse these data to identify patterns in road deterioration and assess which measurement methods and technologies are most suitable for monitoring low-traffic roads.
“We want to understand not only what condition a road is in today, but why it has reached that condition and how it is likely to develop. That information can help road owners decide where maintenance is needed most,” he says.
The work includes statistical analysis and the development of degradation maps that can help counties identify and prioritise roads requiring attention.
Another challenge is that counties do not necessarily collect or use condition data in the same way. Developing a more common approach could therefore make it easier to compare roads, share experience and establish better criteria for maintenance and rehabilitation.
“If we can establish a better and more consistent basis for condition data, it becomes easier to prioritise maintenance and evaluate the costs over the entire lifetime of a road,” says Alzaki.
Two pieces of the same puzzle
Although the two PhD projects address different questions, they are closely connected.
Alzaki’s research can contribute to better knowledge of where roads are deteriorating, why this is happening and how their condition should be measured. Taye’s research addresses the next step: What should be done about it, and how well do different rehabilitation measures work?
Together, the work could give counties a stronger evidence base for deciding both which roads to prioritise and which measures to choose. For road owners responsible for extensive networks and limited maintenance budgets, this is crucial.
“We are very fortunate to have two PhD candidates who both bring relevant professional experience from their home countries into their research,” says project manager Marit Fladvad in SINTEF.
“This is particularly valuable because the project is strongly focused on delivering results that can be put directly to use by the road owners funding the research.”
