In the last few years, transport studies have included many study topics from various disciplines. The second issue in 2023 of Proceedings of the Institution of Civil Engineers – Transport is a good example, reflecting such multi-disciplinary, international and collaborative studies in the transportation field. The researches presented in this issue aim to present the latest developments in transportation systems, road planning, traffic operations, traffic modelling and social needs in transport. On behalf of the journal editorial panel, I hope the published scientific papers contribute to new studies by researchers, engineers, planners, policymakers and students. This issue contains a total of six different studies from many areas proposing solutions for the real-world problems encountered in different countries. All develop solutions using different analysis techniques for the examined real problems. Therefore, this issue has a special importance because it addresses sub-themes related to traffic engineering, planning and modelling, and social effect. A brief overview of all the papers in this issue can be found below.
In the first paper, Chang et al. (2023) examined the ventilation problems in road tunnels. They reported that existing methods use empirical methods to estimate the ventilation time in simulations of construction schedules. In their study, they simulated the wind speed produced during forced ventilation by using a three-dimensional renormalisation group k–ε turbulence model in computational fluid dynamics software. They determined time-dependent variations in the flow and concentration fields during the construction schedules using simulation analysis. Study results showed that the air flow in the tunnel close to the vortex near the working face and branch tunnel was complex but stabilised gradually with increasing distance from this area. They offered different suggestions for the investigated problem in the study. They determined the best entry period for construction workers based on the permissible carbon monoxide gas concentrations, providing a theoretical basis for construction workers to ensure construction progress.
In the paper by Wandelt and Sun (2023), a worldwide, machine-generated airfield database, which includes information on airports, helipads and runways serving airports, was derived and generated using three different machine-processable open data sets as input. In the study, the authors tried to show that a machine-generated airfield database is better than hand-curated data sets using open big data in air transportation. They found that a machine-generated database will hopefully raise the interest of other researchers in the community and lay the foundation for a gold standard for air transportation research because it automatically updates property at any time.
In China, in the paper by Han et al. (2023), speed distribution in ultra-narrow vehicle lane traffic flow was examined in detail. For this aim, traffic flow data and vehicle trajectory data were collected at a four-lane road section with ultra-narrow lanes during off-peak hours. Then, the effect of the ultra-narrow lane on roads was analysed statistically. The data analysis results revealed that the speed difference between vehicles on an ultra-narrow lane is significantly smaller in unsaturated traffic conditions and the free-flow speed is limited by the lane width, both of which indicate safer traffic flow. From the deeper analysis, the greatest speed difference between the vehicle groups was found generally to be less than 3.5 km/h when staggering occurred. Therefore, researchers reported that study results may provide a theoretical basis for research into the car-following theory and decision making while driving in narrow-lane conditions. This result supports previous findings about lane width and driving behaviour in the study results of Aydin (2020) and Aydın (2021).
In Scotland, in the paper by Winter et al. (2023), the performance of a novel road-based landslide early warning system was evaluated in detail. In the study, Winter et al. (2023) examined the trial period of novel early warning signs for landslides on the A83 strategic road in Scotland. The efficacy of the operation of the wig-wag signs and the perceptions and attitudes of road users to the signs were assessed and satisfactory outcomes were found in the trial period. From the observations, 15 of the 17 debris flow events (almost 90%) occurred when the lights were activated; the two events that occurred when the lights were not activated were somewhat different, but were nonetheless classed as ‘false negatives’. Driver survey results also indicated that desired behaviours are promoted by the use of the signs.
In another study conducted in China, by Weng and Chen (2023), new speed–flow models in highway construction work zones were proposed. In the study, traffic data were obtained from six highway work zones in Shanghai, China. After the data collection and extraction process, a work zone capacity distribution model was derived based on these probabilistic speed–flow relationships. Obtained modelling study results showed that work zone length, percentage of heavy vehicles and road roughness had strong effects on the probabilistic speed–flow relationships in the examined zones. They reported that study findings could help traffic engineers evaluate the variability of work zone traffic states and the reliability of traffic management strategies during the operation process.
In Uganda, in the paper by Mbabazi (2023), the social and economic effects of ferry services that link the Ugandan national roads network were examined in detail. In the study, a preliminary data analysis was conducted and results showed the estimated initial capital cost of the nine ferries managed by Uganda National Roads Authority to be US$38.16 million with a current asset value of US$16.36 million. The examined services transport about 3.2 million passengers annually as well as about 1.06 million tonnes of cargo. A contingent valuation method was used to calculate the social value of these ferries and the value of these ferries was estimated as US$10.95 million. It was also found that these ferries generate direct employment worth 126 full-time equivalents (FTEs) annually (1 FTE being 40 h/week). The author also drew attention to the contribution of such services to the sustainable development goals of developing countries.
In summary, the papers in this issue are important for future studies in the fields of traffic engineering, transport modelling and planning. This issue includes many real-site studies from different countries in the world. The study findings of the published papers in this issue will have great contributions to studies and applications of transport authorities and planners.
I hope you enjoy the developed ideas after reading the papers in this issue. I also would like to thank the authors of this issue for their quality peer-reviewed publications. Please visit the Ahead of Print section on Transport's Virtual Library homepage to see the newest articles related to transport studies. Please feel free to email me your questions and comments on this issue.
