Bicycle Level of Service (BLOS) indicators are used to provide objective ratings of the bicycle suitability (or quality) of links or intersections in transport networks. This article uses empirical bicycle route choice data from 467 university students in Trondheim, Norway to test the applicability of BLOS rating schemes for the estimation of whole-journey route choice. The methods evaluated share a common trait of being applicable for mixed traffic urban environments: Bicycle Compatibility Index (BCI), Bicycle Stress Level (BSL), Sixth Edition Highway Capacity Manual (HCM6), and Level of Traffic Stress (LTS). Routes are generated based on BLOS-weighted networks and the suitability of these routes is determined by finding the percentage overlap with empirical route choices. The results show that BCI provides the best match with empirical route data in all five origin–destination pairs, followed by HCM6. BSL and LTS which are not empirically founded have a lower match rate, although the differences between the four methods are relatively small. By iterating the detour rate that cyclists are assumed to be willing to make, it is found that the best match with modelled BLOS routes is achieved between 15 and 21% additional length. This falls within the range suggested by existing empirical research on willingness to deviate from the shortest path, however, it is uncertain whether the method will deliver the comparable findings in other cycling environments.

Digital Twins (DTs) are gaining interest among urban planners and city authorities, but a notable gap exists in fully understanding and effectively applying them to complex and multifaceted transport planning processes. This review is an in-depth exploration of the promising concept of DTs and its implications for transport planning—its current applications and conceptualisations within the domain, focusing on their distinction from traditional transport models and identifying critical areas for further DT development. The review was conducted per PRISMA guidelines to identify 136 relevant studies from 2000 to 2024. Over three-quarters of the articles were published after 2021, indicating a growing focus on digital twins in transport planning. A classical five-component definition of DT, consisting of physical, digital, data model, service and connection components, was adapted and used to synthesise key components of the DTs presented in the studies. Simulations were the most common “data model,” and 31% of studies do not present insight into what “services” could be derived from proposed DTs, indicating a top-down approach to DT development. A prevalent misapplication of the DT concept was observed where most studies conflated basic digital models or shadows as DTs without fully meeting the criteria of real-time data integration or bi-directional interaction with physical systems. Interestingly, mature DTs with real-time data and bidirectional interaction were associated with smaller geographical systems and shorter time-range predictions. This suggested that maturity in transport planning DTs depends not only on technological capabilities but also on the spatiotemporal dimension of the system. The review concludes by suggesting directions towards a revised DT maturity, highlighting the level of maturity needed for “usable DTs”, and advocating the need for a bottom-up approach to DT development rather than the top-down one currently adopted by most studies.

Active travel modes, such as walking and cycling, are essential for fostering sustainable urban transportation. However, their adoption in environmentally challenging areas—characterised by steep slopes, extreme weather, and rugged terrain—presents significant obstacles. This study addresses these challenges by conducting a systematic literature review of studies published between 2000 and 2024 to identify strategies that promote active travel in such contexts. Using a structured five-step methodology, 62 relevant articles were selected and analysed to explore common challenges and propose tailored solutions. The findings highlight critical barriers, including topographical difficulties, harsh climatic conditions, and adverse weather, all of which hinder walking and cycling. To address these barriers, this study identifies a range of solutions, including infrastructure enhancements such as bike lifts, e-bike systems, shaded walkways, and heated pavements, as well as policy measures like financial incentives and disincentive regulations. Importantly, this study makes a deliberate effort to avoid overgeneralised solutions by emphasising the need for interventions that are context-sensitive and tailored to specific environmental challenges, urban scales, and local conditions. By providing options for actionable strategies, this research offers a comprehensive foundation for developing inclusive and sustainable policies that encourage active travel in diverse and environmentally constrained urban settings.