Major Highways Research Articles

Traffic Accident Risk Assessment Framework for Qassim, Saudi Arabia: Evaluating the Impact of Speed Cameras

Saudi Arabia is one of the countries with the highest number of road accidents and associated fatalities in the world. Speeding has been identified as an important cause of increased traffic accidents, which also aggravate their severity. Road safety improvement strategies are primarily based on the accurate identification of accident hotspots. Installing speed cameras at a network level is an expensive road safety measure, and its spatiotemporal effectiveness should be assessed. In this study, a traffic accident risk assessment framework has been developed and implemented on the 84 km long Buraydah Ring Road in the Qassim region of Saudi Arabia. The selected highway was divided into 42 (×2 km long) segments using the ArcGIS software. A risk scoring scheme was developed to incorporate both the frequency and severity of road accidents. Speed cameras installation at various segments showed a 70% decline in total accident counts, 53% in accidents with property damage, 84% decline in accidents causing injury, and complete absence of accidents with fatalities. The 48% segments were identified as hotspots with risk level ≥ medium, while the speed cameras installation completely eliminated the hotspots from the study area. The proposed framework can be implemented on major high-speed highways, accommodating high traffic volumes, for hotspot identification and evaluation of various road safety measures in Saudi Arabia and elsewhere.

Effects of Diesel Engine Emission Controls on Environmental Equity and Justice

The air quality and environmental equity benefits for the accelerated use of diesel particle filter (DPF) and selective catalytic reduction (SCR) systems on heavy-duty diesel trucks are assessed in Oakland, California. The study focuses on communities adjacent to two major freeways: Brookfield Village and Sobrante Park along I-880, heavily affected by truck traffic; and Sequoyah along I-580, where heavy-duty trucks are prohibited. Brookfield-Sobrante has a higher proportion of nonwhite, low-income residents than Sequoyah (97% vs. 76%). We modeled concentrations of nitrogen oxides (NOx), diesel particulate matter (PM), and black carbon (BC) before widespread use of diesel emission controls (2009), after universal adoption of DPFs to control PM emissions (2018), and after universal adoption of SCR to control NOx emissions (2023). Reductions in near-roadway pollutant concentrations in Brookfield-Sobrante were 59% for NOx and 42%–43% for diesel PM and BC by 2018. In Sequoyah, reductions in NOx concentrations were smaller (52%), and diesel PM and BC concentrations increased by 19% and 13%, respectively. While estimated NOx concentrations remain higher in Brookfield-Sobrante compared with Sequoyah, diesel PM and BC concentrations will be similar in both neighborhoods by 2023. Reductions in diesel emissions also led to improvements in environmental equity when quantified by the difference in mean intakes for Brookfield-Sobrante versus Sequoyah. Maintaining these air quality and equity benefits requires that diesel emission control systems remain in good working order over time.

Assessment of geomatics engineering techniques for landslides investigations for traffic safety

Geomatics engineering (GIS, GPS, Remote sensing, and photogrammetry) offers a lower cost and faster prediction of the threat of landslides to road traffic safety. They reduce the cost and the time needed for the monitoring of the active sliding land areas around the highways. The objective is to assess the potential of geomatics engineering in deciding slope failure occurrence after landslide to insure traffic safety. Several types of geomatics data (GPS, Photogrammetry, high resolution satellite images) will be used to predict the threat of landslides on the highway.Landslides around the highways lead to dangerous accidents, significant economic loss and disruption of traffic flow. As a case study, we considered unstable area with continuous landslides where a major highway is traversing and suffers from yearly disruption and accidents due to landslides. An area around the North Highway (Amman-Jerash highway) which connects the capital Amman to three important governorates Irbid, Jerash and Ajloun was studied and analysed using Geomatics engineering techniques to predict its stability after land slide. This highway traverses a mountainous area with repeated unpredicted dangerous landslides after the rainy season. Landslides cause tremendous problems to this artery highway and sometimes corrupt traffic for months. The late landslides occurred in 2017 and 2019 caused massive destruction and disruption of the traffic flow.For the sake of comparison with the used classical methods, the results of land stability detection obtained from geomatics processing were compared with those obtained by the classical methods (based on field and laboratory works). The results (obtained from the use of geomatics techniques) completely agreed with the geo-technique, geologic and water studies using data obtained from the Ministry of Public Works and Housing (MPWH). As a result, Geomatics techniques provided the same detection results faster and at lower cost.

Examining crash injury severity and barrier-hit outcomes from cable barriers and strong-post guardrails on Alabama’s interstate highways

Introduction: This study investigates the impact of several risk factors (i.e., roadway, driver, vehicle, environmental, and barrier-specific characteristics) on the injury severity resulting from barrier-related crashes and also on barrier-hit outcomes (i.e., vehicle containment, vehicle redirection, and barrier penetration). A total of 1,685 barrier-related crashes, which occurred on three major interstate highways (I-65, I-85, and I-20) in the state of Alabama, were collected for a seven-year period (2010–2016), and all relevant information from the police reports was reviewed. Features that were rarely explored before (e.g., median width, barrier length, barrier offset or lateral position, left shoulder width, blockout type, and number of cables) were also collected and examined. Two types of longitudinal barriers were analyzed: high-tension cable barriers installed on medians and strong-post guardrails installed on medians and/or roadsides. Method: Two separate mixed logit (MXL) models were used to analyze crash injury severity in median and roadside barrier-related crashes. Two additional MXL models were separately adopted for median and roadside barrier-related crashes to estimate the probability of three barrier-hit outcomes (vehicle containment, vehicle redirection, and barrier penetration). Results: The results of crash injury severity MXL models showed that, for both median and roadside barrier crashes, barrier penetration, female drivers, and driver fatigue were associated with a higher probability of injury or fatal crashes. The results of barrier-hit MXL models showed that longer barrier length, Brifen cable barrier system, and barrier lateral position were significant predictors of median barrier-hit outcomes, whereas dark lighting condition, driving under the influence (DUI), presence of curved freeway sections, and right shoulder width significantly contributed to roadside barrier-hit outcomes. Conclusions: The MXL model succeeded in identifying several contributing factors of crash severity and barrier-hit outcomes along Alabama’s interstate highways. Practical applications: One study application is to design longer barrier run length (greater than 1230 feet or 0.2 miles) to reduce the barrier penetration likelihood.

Evaluating the impact of traffic activities on the heavy metals concentrations along a major highway in Delta State, Nigeria

Evaluating the impact of traffic activities on the heavy metals concentrations along a major highway in Delta State, Nigeria

Modeling Traffic Flow, Energy Use, and Emissions Using Google Maps and Google Street View: The Case of EDSA, Philippines

The general framework of the bottom-up approach for modeling mobile emissions and energy use involves the following major components: (1) quantifying traffic flow and (2) calculating emission and energy consumption factors. In most cases, researchers deal with complex and arduous tasks, especially when conducting actual surveys in order to calculate traffic flow. In this regard, the authors are introducing a novel method in estimating mobile emissions and energy use from road traffic flow utilizing crowdsourced data from Google Maps. The method was applied on a major highway in the Philippines commonly known as EDSA. Results showed that a total of 370,855 vehicles traveled along EDSA on average per day in June 2019. In comparison to a government survey, only an 8.63% error was found with respect to the total vehicle count. However, the approximation error can be further reduced to 4.63% if cars and utility vehicles are combined into one vehicle category. The study concludes by providing the limitations and opportunities for future work of the proposed methodology.

Time-Resolved Characterization of Indoor Air Quality due to Human Activity and Likely Outdoor Sources during Early Evening Secondary School Wrestling Matches

Despite positive health outcomes associated with physical activity as well as individual and team sports, poor indoor air and environmental quality can adversely affect human health, performance, and comfort. We conducted a 14-month field case study incorporating two winter sports regular seasons (12/2017–2/2019) including analyses of particulate matter (PMx) in air and in dust, carbon dioxide (CO2), temperature, and relative humidity (RH%) during secondary or high school wrestling activities in southern New Jersey, USA. After planning and piloting methods during the first winter sports regular season (12/2017–2/2018), during the second winter sports regular season (1–2/2019), we conducted a purposeful simultaneous real-time sampling midgymnasium adjacent to the wrestling mats. Gymnasium occupancy ranged 100–500 people. Data collected included inhalable PM10 resuspended from floor mats, fine respirable PM2.5, and indoor CO2, temperature, and RH%. Short-term real-time elevated PM10 levels were directly compared with simultaneously documented wrestling match bouts, e.g., student-athlete takedowns and pins. PM10 and PM2.5 levels were compared with other known documented activities indoors (e.g., snack bar) and sources outdoors (e.g., adjacent parking lot and major freeway). To understand CO2, temperature, and RH% data, we characterized the HS gym mechanical ventilation system—no doors or windows outdoors—and recorded occupancy during match hours. Indoor CO2 levels ranged ∼700–1000 ppm during match #1 on 1/23/2019 but ranged from ∼900 to 1900 ppm during match #2 on 1/30/2019, with >1000 ppm for the majority of the time (and throughout the entire varsity match when occupancy was at maximum). Future research should further characterize PM10 constituents in mat dust and indoor air with larger samples of schools and matches.

Throughfall and stemflow are major hydrologic highways for particulate traffic through tree canopies

For one‐third of Earth’s land surface, precipitation passes through tree canopies (as throughfall or stemflow) before entering watersheds. Over a century of research has described fluxes of water and solutes along these “hydrologic highways”, yet little is known about their “traffic” – that is, the organisms and nonliving particulates frequently discarded from water samples after filtration in the lab. A comprehensive understanding of the composition of sub‐canopy precipitation is necessary to estimate the total nutrient and pollutant inputs to watersheds for redistribution downstream, as well as to systematically investigate precipitation effects on organismal exchanges along the atmosphere–plant–soil continuum. Here, we review current concepts and research showing that the hydrologic highways from tree canopies to soil carry ecologically relevant quantities of biologic (viruses, microbes, microfauna, and meiofauna) and abiotic particulates. Their fate may have important consequences for the biogeochemistry and biodiversity of terrestrial systems.

Rockfall analysis in the area of Kakia Skala, Greece

Because rockfalls cause significant hazard on human activities and infrastructure, the rockfall analysis is considered to be very important along roads and on other geotechnical works. Especially, in Greece owing to the complexity of geological structure, the tectonic characteristics, the climate and the high seismicity, this analysis is of great importance. This paper presents the topographical, geological, tectonic and seismic features and determines the Rock Mass Rating and Rockfall Hazard Rating System values of the tectonically disturbed limestones in the area of “Kakia Skala”, which is part of the “Patra–Athens–Thessaloniki–Evzoni (P.A.TH.E.)” motorway—one of the most major highways in Greece. For this reason, after geological and geomorphological investigations, bibliographic references and the characteristics of the road construction (tunnels, embankments, trenches, etc.), the most dangerous positions were identified (eight). Finally, the two most dangerous sites were selected for separate rockfall analysis. The RocFall software is used for the estimation of the unstable blocks trajectories and their kinematic characteristics. The appropriate support measure, with the right dimensions, is selected according to the kinetic energy of the falling rocks, and it is placed at the appropriate location.

Are standardized diesel exhaust particles (DEP) representative of ambient particles in air pollution toxicological studies?

In this study, we investigated the chemical characteristics of standardized diesel exhaust particles (DEP) and compared them to those of read-world particulate matter (PM) collected in different urban settings to evaluate the extent to which standardized DEPs can represent ambient particles for use in toxicological studies. Standard reference material SRM-2975 was obtained from the National Institute of Standards and Technology (NIST) and was chemically analyzed for the content of elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), inorganic ions, and several metals and trace elements. The analysis on the filter-collected DEP sample revealed very high levels of EC (i.e., ~397 ng/μg PM) which were comparable to the OC content (~405 ng/μg PM). This is in contrast with the carbonaceous content in the emitted particles from typical filter-equipped diesel-powered vehicles, in which low levels of EC emissions were observed. Furthermore, the EC mass fraction of the DEP sample did not match the observed levels in the ambient PM of multiple US urban areas, including Los Angeles (8%), Houston (~14%), Pittsburgh (~12%), and New York (~17%). Our results illustrated the lack of several high molecular weight carcinogenic PAHs in the DEP samples, unlike our measurements in major freeways of Los Angeles. Negligible levels of inorganic ions were observed in the sample and the DEP did not contain toxic secondary organic aerosols (SOAs) formed through synchronized reactions in the atmosphere. Lastly, the analysis of redox-active metals and trace elements demonstrated that the levels of many species including vehicle emission tracers (e.g., Ba, Ti, Mn, Fe) on Los Angeles roadways were almost 20 times greater than those in the DEP sample. Based on the abovementioned inconsistencies between the chemical composition of the DEP sample and those of real-world PM measured and recorded in different conditions, we conclude that the standardized DEPs are not suitable representatives of traffic emissions nor typical ambient PM to be used in toxicological studies.

Urban sprawl modelling and prediction using regression and Seasonal ARIMA: a case study for Vellore, India

Analysing the changes in various landuses during the past, identifying the direction and type of urban sprawl, modelling its causative factors and predicting the future sprawl are some of the key areas which urban planners are generally interested in as they help them to properly plan cities in a more efficient way. In the present study, an attempt has been made to address these key areas using open-source geospatial data for the city of Vellore in India which has experienced significant urban growth in recent decades. Landuse maps were prepared using aerial photos, topographic maps and satellite images for the period 1967–2019 and using that a comprehensive urban sprawl analysis was carried out. The results indicated that the major highways that pass-through Vellore have strong influence on urban development as ribbon type of sprawl was witnessed along the principal transportation corridors. This has been confirmed while modelling of causative factors that when distance from highway increases, built-up density decreases. Similarly, the location of central business district (CBD) found to play a crucial role in urban growth as built-up density decreases when distance from CBD increases. Regression models were built to calculate the built-up density at any distance from city centre or major roads in space–time domain. The present study also developed models based on Seasonal ARIMA to forecast the future built-up density for the year 2045 using the built-up densities of 1967, 1991 and 2019. The results showed that more development is expected on suburban areas as those are the places where one can expect development to take place when compared to the interior zones which were already developed much during the past years. The methodology reported in this paper is well applicable for any city or town to analyse the landuse changes, model the causative factors and predict its future sprawl using completely the open-source data.

Physicochemical Characterization and Seasonal Variations of PM10 Aerosols in a Harsh Environment

We have conducted a comprehensive sampling campaign of PM10 pollutants at a site next to a major highway, using standard protocols. Particulate matter (PM) total mass, elemental and chemical/mineral compositions of the fine and coarse fractions of traffic-related PM pollutants were determined using several complementary techniques, including gravimetric analysis, x-ray fluorescence, scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The PM mass concentrations show that PM10 is within acceptable international standards except during dust storms within the sampled periods. Desert dust, crustal minerals, and sea salts are the major natural sources of PM10 pollution. Examples of these minerals are quartz [SiO2], calcite [CaCO3], gypsum [CaSO4·2H2O], palygorskite [(Mg,Al)2Si4O10(OH)•4(H2O], chlorite-serpentine [(Mg,Fe)6AlSi3O10(OH)8], halite [NaCl] and nitratine [NaNO3]. Anthropogenic mineral-based pollutants, such as mascagnite [(NH4)2SO4] and koktaite [(NH4)2Ca(SO4)2·H2O], were also observed to contribute to PM10. Trace elements such as Zn, Cu, Fe, Cr and Mn that are markers for traffic sources, Ni and V that are markers for heavy oil combustion, and Pb, which is attributed to industrial emissions, were also identified in PM10. Seasonal variation of the average total mass concentrations and the average mass concentration of elements emitted from natural sources show that the hot season is associated with higher pollution levels compared to the cold season due to increased dust events in the spring and summer. Correlation coefficients between elements have identified elements originating from common sources such as dust storms (e.g., Si, Ca, Al, Fe, Ti, Mn) and sea breeze (Cl and Na), in addition to anthropogenic elements. Enrichment factors calculations have identified elements that mainly have crustal origins, and elements that are partially or highly enriched by humans. Anthropogenic elements were more enriched during the cold season due to reduced human activities in the summer.

Roadside surveys of drinking and driving in Cameroon

Objective This study aimed to assess the prevalence of drinking and driving on roadways in urban areas and highways in Cameroon, and to determine the associations between drinking and driving and socio-demographic factors. Methods A cross-sectional study of motor vehicle drivers was performed on Fridays, Saturdays, and Sundays between May and September 2020 with three driver groups: (1) random motor vehicle drivers (including riders) on major highways, (2) drivers recruited at car stations in Yaoundé, and (3) at fuel stations in Douala. Alcohol was measured using breathalyzers, and a questionnaire collected socio-demographic data. Results In total, 2402 motor vehicle drivers were asked to participate in the study and 1701 (70.8%) gave informed consent. The vast majority (98.6%) were men. Drivers aged 30-39 years constituted the largest age group on highways and in Yaoundé, whereas 18-29 years was the largest age group in Douala. The highest prevalence of alcohol was observed among drivers in Yaoundé, which included mainly clandestine taxi car drivers and motorcycle taxi riders, where about 30% had blood alcohol concentrations (BAC) above the legal limit of 0.08%. The proportion with BACs above the legal limit was about 6% among the drivers in Douala, which included mainly motorcycle taxi riders, and about 4% among drivers on highways. Conclusions The findings indicate that drinking and driving is a major traffic safety problem on Cameroonian public roads, especially among motorcycle taxi riders and clandestine taxi drivers in towns, which represent the major mass transportation means in the country. Drinking and driving education and legislation should be better developed and enforced in order to reduce the number road traffic crashes.

Small-scale distributions of polycyclic aromatic hydrocarbons in urban areas using geospatial modeling: A case study using the moss Orthotrichum lyellii in Portland, Oregon, U.S.A.

Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants that are costly to measure with air quality instruments. We used a spatially balanced sample of an epiphytic moss, Orthotrichum lyellii, to develop fine-scale maps of atmospheric PAHs across residential areas of Portland, Oregon. The unusual abundance of this stress-tolerant species enabled us to systematically collect a large sample (n = 350) on a 1 × 1km grid across the city. This provided the unique opportunity to investigate potential effects of more than 20 factors on PAH concentrations in moss, including emissions sources, tree canopy cover, relative elevation, short-term weather, and nuance of sample collection. We measured 20 PAHs in moss samples and assigned them to 4 groups for analysis based on molecular weight (MW): the Naphthalene, Low, Medium, and High MW groups. Spatial regression models explained a modest amount of variation in PAH concentrations in moss, with spatial structure increasing as MW increased. Motor vehicle emissions were the only PAH source we detected and was highly significant in all models. Deciduous tree cover correlated with lower PAH concentrations in moss for all except the high MW group. Short-term weather and nuance of sample collection, like height on the sampled tree, tree taxonomic family, and whether sample was primarily collected from a branch or bole, had surprisingly large effects on all groups. Overall, results aligned with expectations based on each group's dispersal potential due to MW. All PAH groups were highest over downtown Portland, along major highways, and lowest in parks and outer neighborhoods, although the details varied. Our results supported two common themes in studies directly measuring PAHs: the importance of roads as an emissions source in residential areas, and the potential for trees to reduce atmospheric concentrations. Moreover, the large effects of weather and sampling nuance have critical implications for the design of future studies.

A Multifeatures Spatial-Temporal-Based Neural Network Model for Truck Flow Prediction

The majority of studies on road traffic flow prediction have focused on the flow of passenger cars or the flow of traffic as a whole, which ignore the significant impact of trucks with different sizes and operational characteristics on traffic flow efficiency. Therefore, in this paper, we focus on truck traffic flow and propose a Multifeatures Spatial-Temporal-Based Neural Network model (M-BiCNNGRU) to improve its prediction. The proposed model not only comprises conventional temporal characteristics and spatial relationships but also includes a range of multifeatures. These multifeatures include policy limit, optimal time delay, road resistance, and traffic congestion state. The impacts of upstream and downstream road sections are considered on the spatial relationship by using a Convolutional Neural Network (CNN). A Bidirectional Gated Recurrent Unit (Bi-GRU) is employed to account for the temporal characteristics. To evaluate the proposed model, traffic flow data were collected from a major expressway in Beijing and the results were compared with those derived from existing models. The results show that the prediction accuracy of the BiCNNGRU model, with spatial-temporal characteristics, and the M-BiGRU model, with multifeatures and temporal, is, respectively, 4.13% and 2.15% greater than that of the Bi-GRU model, with temporal characteristics. The prediction accuracy of the proposed M-BiCNNGRU model is 92.86%, which is 7.12% greater than that of the Bi-GRU model and 13.83% greater than that of the Support Vector Regression (SVR) model. In general, therefore, the proposed M-BiCNNGRU model, which combines multifeatures, temporal characteristics, and spatial relationships, can significantly improve accuracy in predicting truck traffic flow.

Portable WIM Systems: Comparison of Sensor Installation Methods for Site-Specific Traffic Data Measurements

Abstract As an alternative to costly permanent weigh-in-motion (WIM) stations that are mostly limited to major interstate highways, portable WIM systems are often used as a substitute or supplement to routinely collect site-specific traffic data (both volume and weight) for pavement design and analysis applications. By comparison, portable WIM systems are cost effective and much easier to install at any desired highway site/location. However, accuracy, reliability, and data quality have been some of the key challenges of portable WIM systems. As a means of addressing these challenges, this field pilot study was undertaken to comparatively evaluate two different sensor installation methods for routine traffic data measurements: the pocket tape and metal plate methods. The two methods were comparatively evaluated in terms of their practicality, simplicity of installation, cost effectiveness, resource/manpower needs, environmental sensitivity and endurance, consistency, data accuracy, and statistical reliability of the traffic data measurements. Along with a side-by-side field validation using permanent WIM data, the findings from the study indicated that the metal plate sensor installation method is superior to the pocket tape method, particularly in terms of data accuracy, data quality, statistical reliability, and endurance. Its traffic data accuracy rate was found to be 87∼91 % compared with 79 % for the pocket tape method, which exhibited a significant loss of sensitivity and data accuracy after 7 d of traffic measurements. Overall, the conclusions of this study provide technical merit and preference to the metal plate method over the pocket tape sensor installation method, particularly for traffic data measurements exceeding 7 d.

A community noise survey in Southwest Detroit and the value of supplemental metrics for truck noise

Noise exposure can affect sleep, health and cognitive performance, and it disproportionately affects communities of color. This study has the objective of evaluating both conventional and supplemental noise metrics in a community noise survey examining Southwest Detroit, Michigan, a densely populated and industrialized area with extensive truck traffic on residential streets. Sound pressure level (SPL) monitors were deployed at 21 residential sites within 900 m of a major interstate highway. With assistance from youth volunteers, continuous SPL measurements were obtained for 1.5–7 days at each site, and short-term vehicle counts on local roads were recorded. We calculated conventional noise metrics, including the day-evening-night average sound level LDEN and the 90th percentile 1-hr maximum L10(h), and evaluated the effect of distance from highways, traffic volume, time-of-day, and other factors. Supplemental metrics potentially appropriate for intermittent traffic noise were calculated, including fraction of time over specific SPL thresholds using a new metric called FDEN, which is the fraction of time over 60, 65 and 70 dB during night, evening and daytime periods, respectively, and a peak noise metric called L2P(h), which utilizes the 98th percentile SPL within time blocks to increase robustness. The conventional metrics indicated five sites that exceeded 70 dB, and the highest noise levels were found within ~50 m of truck routes, arterials and freeway ramps. The estimated impact of truck traffic ranged up to 17 dB for hourly averages and to 33 dB for 1-s peaks. The conventional metrics did not always capture short-term noise exposures, which may be especially important to annoyance and sleep issues. In addition to showing widespread exposure to traffic noise in the study community that warrants consideration of noise abatement strategies, the study demonstrates the benefits of supplemental noise metrics and community engagement in noise assessment.

Investigating the Invasion Pattern of the Alien Plant Solanum elaeagnifolium Cav. (Silverleaf Nightshade): Environmental and Human-Induced Drivers.

Invasive alien plant species have impacts on nature conservation, ecosystem services and agricultural production. To identify environmental and human-related drivers of the invasion of Solanum elaeagnifolium (Solanaceae)—one of the worst alien invasive plants worldwide—we conducted an extensive drive-by survey across the Greek territory (presence/absence data; all national major multilane highways; 12–25% of the remaining road network; driven 3–5 times during 2000–2020). These data were linked in GIS with (i) physical environmental attributes (elevation, climate, soil properties) and (ii) type and intensity of human-related activities (land uses, settlements and road type). Compared to previous records, our survey showed that the range of S. elaeagnifolium increased by 1750% during the last decades, doubling its main distribution centers and reaching higher elevations. Our study revealed that the presence of S. elaeagnifolium is associated with (i) higher maximum temperatures and precipitation in summer and low precipitation in winter, as well as with (ii) soil disturbance related to agricultural activities, settlements and road networks, thus facilitating its spread mainly at low altitudes. Our study elucidates the current invasion pattern of S. elaeagnifolium and highlights the urgent need for its widespread monitoring, at least in the noninvaded areas in Greece that have been surveyed in this study. Preventative measures and integrative initiatives should be implemented quickly, and urgently incorporated into current agricultural, road network and conservation-management regimes.

Bridge-type buildings on small rivers of cities as a solution to transport problems

The article deals with bridge-type buildings over small rivers of cities as an urban planning tool that facilitates transport problems in these cities. A large number of small rivers in cities, which create insurmountable obstacles for vehicles, separate urban districts preventing vehicles from moving from one district to another taking the shortest route. This circumstance forces vehicles to travel on major highways, overloading them and creating essential congestions. Embankments along small rivers also lead traffic flows to the main highways. As a result of the conducted research, the authors propose to create bridge-type buildings with transport turnpikes through these obstacles, using them for the infrastructure necessary for the city. Such bridge-type buildings can be constructed at the level of embankments, avoiding access trestles that significantly clutter up the adjacent streets and require reconstruction of the surrounding territories. Small bridge-type buildings for these purposes with a span of up to 25 m based on steel-reinforced concrete structures are not expensive and can be financed by investors in case of their interest to rent premises located on the floors of such bridge-type buildings.

A Geomorphic Approach for Identifying Flash Flood Potential Areas in the East Rapti River Basin of Nepal

Basin geomorphology is a complete system of landforms and topographic features that play a crucial role in the basin-scale flood risk evaluation. Nepal is a country characterized by several rivers and under the influence of frequent floods. Therefore, identifying flood risk areas is of paramount importance. The East Rapti River, a tributary of the Ganga River, is one of the flood-affected basins, where two major cities are located, making it crucial to assess and mitigate flood risk in this river basin. A morphometric calculation was made based on the Shuttle Radar Topographic Mission (SRTM) 30-m Digital Elevation Model (DEM) in the Geographic Information System (GIS) environment. The watershed, covering 3037.29 km2 of the area has 14 sub-basins (named as basin A up to N), where twenty morphometric parameters were used to identify flash flood potential sub-basins. The resulting flash flood potential maps were categorized into five classes ranging from very low to very high-risk. The result shows that the drainage density, topographic relief, and rainfall intensity have mainly contributed to flash floods in the study area. Hence, flood risk was analyzed pixel-wise based on slope, drainage density, and precipitation. Existing landcover types extracted from the potential risk area indicated that flash flood is more frequent along the major Tribhuvan Rajpath highway. The landcover data shows that human activities are highly concentrated along the west (Eastern part of Bharatpur) and the east (Hetauda) sections. The study concludes that the high human concentrated sub-basin “B” has been categorized as a high flood risk sub-basin; hence, a flood-resilient city planning should be prioritized in the basin.