Quantifying road traffic emissions embedded in a multi-objective traffic assignment model

In a road network, drivers typically seek to minimize their own travel time, often affecting system-wide performance. With the increasing environmental awareness, for an efficient traffic assignment (TA), besides concerns with travel times, traffic managers should not neglect the system-wide level of both global and local pollutant emissions. Measuring road traffic emissions can be costly and different models based on vehicle-specific parameters with many input variables have been suggested in the literature. This paper proposes a simple way to quantifying carbon dioxide (CO2) and nitrogen oxides (NOX) emissions with only average speed as input variable and presents a multi-objective TA approach that seeks to minimize system-wide travel time, distance travelled (associated with fuel consumption) and global and local pollutant emissions. A real-world case study on an intercity corridor with many alternative routes between two zones is presented. Experiments considering TA based on travel time, and on time, distance travelled, and pollutant emissions are reported. Results highlight that system optimal distribution based on the suggested multi-objective TA based on three components yields savings in terms of distance travelled (2.6%) and emissions (1.3% for CO2 and 1.1% for NOX), but penalizes travel time 3%, which is translated in an increase of 20sec per vehicle, when compared to the solution only focused on minimizing travel time. The developed methodology is a suitable tool for traffic analysts to predict vehicle system-wide travel time, distance travelled and pollutant emissions with few vehicle information but with a reasonable detail for a specific traffic flow on a given road network, to support analyses for sustainable transport policies and may be used, for instance, as an environmental impact component of a pricing scheme, traffic signal control strategies based on emissions reduction, or to minimize congestion by giving prior information to drivers on the specific routes to be chosen.publishe

Assessing the emission impacts of autonomous vehicles on metropolitan freeways

While recent studies demonstrate the societal and economic benefits of driverless vehicles, little is known about the emission impacts of autonomous vehicles (AVs) in the context of mixed traffic. This paper explores the environmental impacts of AVs along an urban freeway corridor in a metropolitan area using Vehicle Specific Power (VSP) and EMEP/EEA emission methodologies paired with VISSIM traffic model. Three different AV penetration rates were implemented for through traffic along a freeway corridor in the city of Porto (Portugal) by considering long-term market predictions (10%, 20% and 30%). Afterwards, these scenarios were compared to current situation in terms of carbon dioxide, carbon monoxide, nitrogen oxides and hydrocarbon emissions, and travel time and stop-and-go situations. The emissions and traffic performance of each scenario were evaluated on three levels: a) overall study domain; b) corridor; c) impact of AVs on conventional vehicles (CVs). AVs yielded small savings in emissions in the overall study domain for automation levels below 30% (differences in traffic performance and emissions were not statistically significant). Corridor-level analysis showed decreases of 5% in emissions can be expected with AVs technology, but it penalizes travel time up to 13% for both AV and CV, when compared to the existing situation.publishe

Effect of ciprofloxacin dosages on the performance of sponge membrane bioreactor treating hospital wastewater

© 2018 Elsevier Ltd This study aimed to evaluate treatment performance and membrane fouling of a lab-scale Sponge-MBR under the added ciprofloxacin (CIP) dosages (20; 50; 100 and 200 µg L−1) treating hospital wastewater. The results showed that Sponge-MBR exhibited effective removal of COD (94–98%) during the operation period despite increment of CIP concentrations from 20 to 200 µg L−1. The applied CIP dosage of 200 µg L−1 caused an inhibition of microorganisms in sponges, i.e. significant reduction of the attached biomass and a decrease in the size of suspended flocs. Moreover, this led to deteriorating the denitrification rate to 3–12% compared to 35% at the other lower CIP dosages. Importantly, Sponge-MBR reinforced the stability of CIP removal at various added CIP dosages (permeate of below 13 µg L−1). Additionally, the fouling rate at CIP dosage of 200 µg L−1 was 30.6 times lower compared to the control condition (no added CIP dosage)

Effects of an exercise programme with people living with HIV: Research in a disadvantaged setting

This study aimed to analyse the physical health effects of a community based 10-week physical activity programme with people living with HIV. It was developed, implemented and evaluated in a disadvantaged community in South Africa. A pre-post research design was chosen. Major recruitment and adherence challenges resulted in a small sample. Among the 23 participants who took part in both baseline and final testing, compliant participants (n = 12) were compared to non-compliant participants (n = 11). Immunological (CD4, viral load), anthropometric (height, weight, skinfolds and waist to hip ratio), muscular strength (h1RM) and cardiopulmonary fitness (time on treadmill) parameters were measured. The compliant and non-compliant groups were not different at baseline. Muscular strength was the parameter most influenced by compliance with the physical activity programme (F = 4.516, p = 0.047). Weight loss and improvement in cardiopulmonary fitness were restricted by the duration of the programme, compliance and influencing factors (e.g. nutrition, medication). The increase in strength is significant and meaningful in the context, as the participants goals were to look healthy and strong to avoid HIV related stigma. The improvements in appearance were a motivational factor, especially since the changes were made visible in a short time. Practical implications for health promotion are described. More research contextualised in disadvantaged settings is needed.DHE

Multi-Criteria Assessment of crosswalk location on a corridor with roundabouts: Incorporating a Noise related Criterion

Traffic noise is an important source of environmental stress that can damage human health. This phenomenon may be sensitive nearby roundabouts where noise levels may exceed exposure limits. However, the quantification about noise perceived by pedestrians at influence areas of roundabouts is lacking. This research assessed the characteristics of noise along an urban corridor with two roundabouts. A deeper understanding about the exposure to noise levels perceived by pedestrians is a contribution of the paper. The specific objectives are: 1) to characterize corridor-specific operations in terms of traffic and pedestrian performance, carbon dioxide and nitrogen oxide emissions, and noise; and 2) to explore the differences in the optimal crosswalk locations considering above-related criteria. Traffic and pedestrian volumes, vehicle dynamic and noise data were collected during morning and evening peak periods in the selected site. Traffic and pedestrian performance, and vehicular emissions were evaluated using VISSIM traffic model and Vehicle Specific Power (VSP), respectively. Traffic noise was estimated with a semi-dynamical model and an estimation of the corridor Source Power Level (SPL) was used as a distance-free parameter to be compared with other emissions. Finally, a Genetic Algorithm (GA) was applied to find optimal crosswalk locations. It was found that crosswalks nearby the present location (PC = 33 m) provided a good balance among traffic and pedestrian performance, emissions and noise, regardless of peak period. The inclusion of noise related-criteria resulted in some optimal locations next roundabout exit section (13-23 m) mostly due to low pedestrian volumes in the study locations

Descriptions of Scottish Priority Marine Features (PMFs).

Background The seas around Scotland are rich and diverse – Scotland’s position at the edge of the continental shelf, the long coastline, large area of sea and the mixing of warm and coldwater currents combine to make its waters a special place for marine wildlife and habitats. Scotland has over 18,000 km of coastline and its inshore and offshore areas are among the largest of any EU country, representing 13% of all European seas. Scotland’s seas are of outstanding scenic, historical and cultural value and are part of the national identity at home and abroad. The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers and duties to ensure that our seas are managed sustainably for future generations, integrating the economic growth of marine industries with the need to protect these assets. Measures to conserve Scotland’s marine natural heritage are based on a three pillar approach, with action at the wider seas level (e.g. marine planning or sectoral controls); specific species conservation measures (e.g. improved protection for seals); and through site protection measures - the identification of new Marine Protected Areas (MPAs). To help target action under each of the three pillars, Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have generated a focused list of habitats and species of priority conservation importance - the Priority Marine Features (PMFs). The aim of the current study was to produce a descriptive catalogue of the Scottish PMFs (including component habitats and species where appropriate) to serve as a reference for future nature conservation action. Whilst derived from available existing accounts, the succinct 1-page descriptions are written from a Scottish perspective, refining, but clearly linking to more generic UK, EC or OSPAR (Oslo and Paris Commission) commentary. Available information on the geographic distribution of the features was collated as part of the project and a summary map is provided in each description. Main findings This project has generated a descriptive catalogue of the 81 PMFs that have been identified in the seas around Scotland (out to the limit of the UK continental shelf). The list comprises 26 broad habitats (e.g. burrowed mud), seven low or limited mobility species (e.g. ocean quahog) and 48 mobile species, including fish (e.g. blue ling) and marine mammals (e.g. minke whale). Information on the distribution of the PMFs was collated within a Geographic Information System (GIS). This is the first time that data about such a diverse range of Scottish marine nature conservation interests have been compiled within a single repository. These data have and will be used in conjunction with other contextual base-mapping to inform the development of nature conservation advice and commentary (e.g. in the production of the Scotland’s Marine Atlas - Baxter et al., 2011). The feature distribution mapping used in the production of this report is being made available to view online via the National Marine Plan Interactive web portal (NMPi - http://www.gov.scot/Topics/marine/seamanagement/nmpihome). As new or refined data on Scottish PMFs become available, these will be fed into updates to the project geodatabase and NMPi

The potential of metering roundabouts: influence in transportation externalities

Roundabouts are increasingly being used on busy arterial streets for traffic calming purposes. However, if one roundabout leg is near a distribution hub, e.g. parking areas of shopping centers, the entry traffic volumes will be particularly high in peak hours. This paper investigated a partial-metering based strategy to reduce traffic-related costs in a corridor. Specifically, the resulting traffic performance, energy, environmental and exposure impacts associated with access roundabouts were studied in an urban commercial area, namely: a) to characterize corridor operations in terms of link-specific travel time, fuel consumption, carbon dioxide and nitrogen oxides emissions, and noise costs; b) to propose an optimization model to minimize above outputs; and c) to demonstrate the model applicability under different traffic demand and directional splits combinations. Traffic, noise and vehicle dynamics data were collected from a corridor with roundabouts and signalized intersections near a commercial area of Guimarães, Portugal. Microscopic traffic and emission modeling platforms were used to model traffic operations and estimate pollutant emissions, respectively. Traffic noise was estimated with a semi-dynamical model. Link-based cost functions were developed based on the integrated modeling structure. Lastly, a Sequential quadratic programming type approach was applied to find optimal timing settings. The benefit of the partial-metering system, in terms of costs, could be up to 13% with observed traffic volumes. The efficiency of the proposed system increased as entering traffic at the metered approaches increased (~7% less costs). The findings let one to quantify metering benefits near shopping areas