Urban Science

Transit Signal Priority (TSP) enhances transit reliability by minimizing delays at signalized intersections, but its broader implementation is often hindered by organizational and procedural challenges. Although many studies have examined the technical performance of TSP systems, fewer have explored the organizational, regulatory, and procedural factors that affect their successful implementation. This study investigates TSP business procedures across multiple U.S. states by conducting structured interviews with key stakeholders and performing a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis. The study identified recurring barriers, including unclear leadership, staffing shortages, inconsistent permitting processes, incompatible equipment, and outdated infrastructure. In contrast, successful programs relied on regular interagency coordination, assigned TSP staff, centralized management, and simplified funding processes. We propose strategies such as assigning a lead agency, streamlining permitting through blanket procedures, shifting to cloud-based control systems, and linking grant funding to performance data.

Transportation remains one of the sectors with the highest GHG emissions in urban areas, forming around a third of household footprints in affluent countries like the Nordics and being the main source of particulate matter emissions in urban areas around the world. This study focuses on the Reykjavík Capital Area in Iceland, which is known for its car-centricity and where modal shift remains a major challenge. The study examines barriers to modal shift to understand why Reykjavík residents are reluctant to change their transport modes away from private cars. The study uses softGIS survey data gathered in 2025 of 1801 respondents. The results show that mobility remains car-dominated, with even regular public and active-mode users owning a car for running errands. The main barriers for switching to public or active modes include long travel distances, high travel time need, an unreliable public transport system, and difficulties running errands. Slight differences emerged between native and non-native residents’ barriers, with the latter being more likely to be impacted by price and connectivity issues. The study further recognizes the potential impact of climate awareness and education, as people with a stronger belief in individual impact on climate were less likely to find these aspects to be a barrier.

Urban regeneration is increasingly expected to integrate environmental resilience, social equity, and cultural heritage alongside economic objectives. This narrative review examines how nature-based solutions (NbS) can be embedded within regeneration strategies through ecological landscape planning and design. A structured search of peer-reviewed literature and policy reports identified 34 academic studies and 13 reports that were coded and synthesised into three thematic areas: (i) NbS typologies and applications, including urban forests, blue–green infrastructure, and landscape-led regeneration; (ii) governance frameworks addressing equity, participation, anti-displacement safeguards, and cultural sensitivity; and (iii) methodological advances such as Geographic Information Systems (GIS)-based spatial analysis, multi-criteria decision frameworks, microclimate modelling, and participatory co-design tools. The review finds that NbS can enhance climate adaptation, biodiversity, and community wellbeing, yet implementation often remains fragmented because of governance barriers and uneven policy integration. Strengthening participatory processes, embedding culturally informed design principles, and incorporating anti-displacement measures are essential to ensure socially just outcomes. Strategic instruments, particularly Strategic Environmental Assessment (SEA), combined with GIS and multi-criteria tools, can support more coherent long-term decision-making. Future research should prioritise cross-sectoral policy coordination, long-term monitoring, and inclusive governance to ensure that NbS-driven regeneration contributes to equitable, resilient, and culturally grounded urban futures.