Aug 2026· Future Transportation· Vol 6, pp. 179· 0 citations· 40 references
Abstract
Improving emergency vehicle mobility in congested urban environments is a critical challenge for transportation systems. Although roadway capacity expansions, such as widening roads, are often deployed to reduce congestion, their impact on emergency response performance is not always guaranteed, especially when delays concentrate at critical intersections. This study investigates how roadway capacity expansion affects emergency vehicle performance by using a microscopic traffic simulation framework. The study was applied to a real urban corridor in Mohammedia, Morocco, to provide a solid base for simulations with real-world conditions. A SUMO model was calibrated to represent two roadway configurations: a baseline two-lane layout and a three-lane post-widening scenario. Traffic volumes from 1056 to 3520 vehicles per hour were simulated, and performance was assessed using three emergency-specific indicators: Emergency Response Time (ERT), Delay Ratio (DR), and Priority Mobility Index (PMI). An initial single-run comparison suggested a substantial ERT reduction under moderate demand (343.40 s to 270.90 s, 21.11%); however, a 30-seed replication with paired Wilcoxon signed-rank tests shows that this and nearly all other widening effects are not statistically distinguishable from stochastic simulation noise. Only one of 12 emergency vehicle comparisons (Priority Mobility Index at 18:00) reached significance, and it favored the baseline configuration; none of 12 general traffic comparisons improved significantly, and general traffic was significantly slower under the widened configuration at 22:00 (p < 0.01). A supplementary sensitivity analysis (±20% emergency vehicle demand share) further shows that Delay Ratio conclusions are considerably more sensitive to this assumption (up to 34% relative change) than ERT or PMI (under 8%). These findings indicate that, in this network, roadway capacity expansion alone does not deliver a statistically robust improvement in either emergency vehicle or general mobility, and that a persistent signalized-intersection bottleneck remains the dominant constraint irrespective of lane geometry. The study provides a replicable, statistically validated simulation framework for assessing roadway capacity expansion effectiveness and cautions against single-run comparisons, which can substantially overstate the causal effect of infrastructure interventions in microscopic traffic simulation studies.
Expressways are designed to facilitate uninterrupted traffic flow; however, localized roadside features such as bus laybys disrupt vehicle dynamics and reduce operational capacity. While classical speed–density models provide theoretical foundations for freeway analysis, localized disturbances are frequently omitted from conventional modeling. This study evaluates the speed–density relationship of passenger cars on a basic expressway segment adjacent to a bus layby along the Federal Highway (KM 17) in Selangor, Malaysia. Traffic data were collected across peak and off-peak periods using elevated video recordings and analyzed via Tracker motion-analysis software across 36 five-minute intervals. Comparative evaluation against classical single-regime models demonstrated that the linear Greenshields model ($V_s = 116.97 - 1.381k$) provided the most robust fit, explaining 75.05% of the variation in passenger car speed ($R^2 = 75.05\%$, $F = 102.27$, $p < 0.001$). The empirical findings indicate that each 10-unit increase in density ($pcu/km$) induces an approximate 14 $km/h$ reduction in speed, largely driven by lane-changing turbulence and deceleration near the layby weave zone. These results underscore the need for infrastructure authorities to incorporate localized disturbance factors into expressway capacity planning and offer actionable insights for optimizing bus layby geometry and setback distances to preserve highway efficiency.
Ifham Fathi Sayuti, T. Besar, Noorazlan Hasnim et al.· International journal of res...· 0 citations
Abstract Land-use patterns play a crucial role in trip generation and spatial demand, leading to high traffic congestion in urban areas due to a rapidly increasing population. Today, the urban movement in Baghdad is paralyzed by heavy traffic congestion at major intersections, and this crisis is closely linked to poor integration between land use as an essential factor in transportation planning, and traffic modelling and management. Traditional models, however, concentrate more on traffic volume and less on the dynamics of functionality in an urban setting. This gap is addressed by incorporating Mixed Use (MU) into traffic performance modelling to investigate its influence on “Traffic congestion” (measured as back-of-queue length). The approach used a two-phase Multiple Linear Regression (MLR) analysis with 120 independent observation periods at high-density intersections. Traffic flow inputs were validated rigorously by comparing outputs from the SIDRA Intersection software and the Highway Capacity Manual (HCM 2010) methods with traffic footage. By using an Entropy Index to measure functional diversity (Mixed use), the research extended the range of simple density measurement on involving mixed use effects on intersection capacity. The results prove that the inclusion of mixed-use variables significantly improve model performance (from R2=0.613 to R2=0.840). A main outcome from this research is that contrary to classical urban theory, in Baghdad, higher land-use diversity causes more congestion. This “Mixed Use Paradox” is caused by natural functional overlaps and gross underinvestment in infrastructure that causes shaping “functional friction” at-grade intersections. Additionally, the research points out that commercial density and high volume “trip bursts” of people driving to school from an educational (or college) zone act as major contributors to delays and are exacerbated by excessive through traffic pushing past smaller local facilities. These results are important for transportation planning and indicate that simply expanding roads will not solve Baghdad’s traffic woes. What we need, rather, is an approach that coordinates heterogeneous land use with intelligent traffic signalization and structural deconcentration to address the functional overlap that currently clogs the city’s network.
Ishraq Hameed Naser, Fatin Hadi Megtoof, Ahmad Benwan Hassan· Civil and Environmental Engi...· 0 citations
Cities are increasingly addressing mobility challenges by restricting road traffic, particularly traditional road vehicles that generate greenhouse gas emissions. As an alternative, unmanned aircraft systems (UASs) are emerging as a promising solution for future mobility, offering fast, quiet, cost-effective and environmentally friendly operations. For last-mile delivery, small drones operating at low altitudes are considered especially promising and are already being deployed in some urban areas. According to the EU Drone Strategy 2.0, drone services could generate a market of 14.5 billion and create 145,000 jobs in Europe by 2030. As this sector is still in its early stages, there is a significant uncertainty about the optimal organisation of urban air traffic. In this paper we present a realistic prognosis of how unmanned traffic over a city will utilise the urban very-low-level airspace and assess it using two concepts of operations, with non-structured or structured airspace, both aiming to facilitate the coexistence of competitors sharing the same urban low level airspace. The two concepts are evaluated with delivery operations at scale for a large and densely populated European city. Results for a normalised scenario of 3500 daily operations show that structured airspace produces more conflicts than non-structured airspace (e.g., 316 vs. 54, respectively), and that only for the non-structured airspace can all conflicts be solved with a simple strategic altitude reassignment (vs. 10% of unresolved conflicts for structured airspace). The artificial organisation of slim urban airspace may limit the scalability of business delivery while not reducing the conflict rate.
Marc Melgosa, J. Kuljanin, Jairo Lopez et al.· Drones· 0 citations
Kathmandu Valley faces acute urban mobility challenges, including severe traffic congestion, a disproportionately high share of fossil fuel dependent private vehicles, severely degraded pedestrian and cycling infrastructure, and decades of unplanned urban expansion that has consumed road reserves and public space. These conditions impose measurable costs on public health, economic productivity, and environmental sustainability, and they require a structured, evidence informed response grounded in local spatial conditions rather than generic policy templates. This study presents a planning level feasibility assessment for an integrated green urban transportation system specifically tailored to the Kathmandu Valley context, with the Gaushala-Ratopul corridor selected as a representative pilot study area. Field observations were conducted at four locations within the corridor during weekday morning peak hours (8:00–9:00 am), recording vehicle counts ranging from approximately 85 vehicles per hour at the heritage adjacent Jaya Bageshwori Road to approximately 560 vehicles per hour on the Ring Road segment, with motorcycles and microbuses constituting the dominant modes. An Origin and Destination (O&D) survey engaged 35 respondents across five stakeholder categories: daily commuters, shop owners, students, transport workers, and traffic police through purposive sampling at key corridor nodes. A pedestrianisation acceptance survey administered to eight accessible residents and business operators along Jaya Bageshwori Road recorded positive opinions from six respondents (75%), treated as an exploratory qualitative indicator rather than a statistically representative finding. Based on these field observations and secondary evidence from international case studies, the study proposes a phased framework of interventions encompassing pedestrian zone creation, dedicated cycling infrastructure across three spatial typologies, Bus Rapid Transit (BRT) corridor development on two proposed routes, electric vehicle (EV) adoption incentives, smart traffic management through Automatic Number Plate Recognition (ANPR), and integrated digital mobility platforms. Alignment with Sustainable Development Goals 6, 7, and 11 is articulated through measurable indicator linkages supported by international precedent evidence. The proposed framework explicitly acknowledges the absence of transport simulation, emission modelling, and demand forecasting limitations that constrain the study to a planning level contribution and identifies these as priorities for future engineering level investigation.
Surakshya Basnet, Namaraj Lamichhane, Nishma Rajan Magar et al.· Discover Vehicles· 0 citations
Urban road congestion in Ambon City is influenced by high traffic demand and intensive roadside activities, particularly along commercial corridors, which reduce effective road capacity and disrupt traffic flow. Objective: This study aims to evaluate the operational performance of selected urban road sections in Ambon City and identify critical corridors requiring priority traffic-management interventions. Methodology: An analytical–numerical approach based on the Indonesian Road Capacity Manual (MKJI 1997) was applied. Primary data were collected through field observations and traffic-volume counts at seven observation points along Jl. Slamet Riyadi, Jl. Tulukabessy, Jl. Rijali, Jl. Kakialy, and Jl. Diponegoro. Traffic flow (Q), road capacity (C), and degree of saturation (DS) were analyzed to determine operational performance. Findings: Jl. Slamet Riyadi (DS = 1.30), Jl. Tulukabessy (DS = 1.68), and Jl. Kakialy (DS = 1.09) operate at Level F, indicating forced-flow conditions where traffic demand exceeds practical capacity. In contrast, the three observation points on Jl. Rijali recorded DS values of 0.14–0.69, while Jl. Diponegoro recorded a DS of 0.61, indicating free-to-stable traffic conditions. Implications: Traffic-management interventions should prioritize Jl. Tulukabessy, Jl. Slamet Riyadi, and Jl. Kakialy through parking control, reduction of roadside friction, regulation of roadside access, and feasible geometric improvements. These findings can support local authorities in prioritizing traffic-management and infrastructure programs. Originality: This study integrates empirical traffic flow, capacity, and saturation measurements with localized traffic-conflict conditions across strategic urban corridors, extending MKJI 1997 from conventional capacity analysis into a practical framework for identifying and prioritizing critical urban road interventions.
Lenora Leuhery· International Journal for Sc...· 0 citations
Urban transport emissions are a major contributor to climate change and urban air pollution. Although previous studies have demonstrated that traffic demand, fleet electrification, and driving behavior individually influence vehicular emissions, their combined effects under different congestion conditions remain insufficiently understood. This study investigates the interactions among these factors using the microscopic traffic simulator SUMO (Simulation of Urban MObility). A synthetic urban corridor consisting of five signalized intersections was developed to represent arterial roads in medium-sized cities. A full factorial experimental design was implemented by considering three traffic demand levels, three electric vehicle adoption percentage levels, and three driving behavior profiles, resulting in 27 experimental scenarios with 10 stochastic replications per scenario. Traffic performance and pollutant emissions were evaluated to quantify both the individual and interaction effects of the experimental factors. The results indicate that traffic demand is the primary determinant of CO2 and NOx emissions, while fleet electrification substantially reduces emissions, particularly under congested conditions. Driving behavior also plays a role by influencing acceleration and deceleration patterns. Furthermore, statistically significant interaction effects among the experimental factors (p<0.05) reveal the benefits of fleet electrification considering the traffic demand and the driving behavior. These findings contribute to the understanding of sustainable urban mobility by providing a comprehensive assessment of how traffic demand, fleet electrification, and driving behavior jointly influence urban traffic performance and vehicle emissions, offering valuable insights for the design of integrated transportation and environmental policies.
Cesar L. González, Juan Sánchez, H. Espitia· Vehicles· 0 citations
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