1,721,065 research outputs found
Transport impacts of household waste recycling centres
No full textHousehold waste recycling centres (HWRCs) evolved from civic amenity sites (CAS) introduced by the Civic Amenities Act 1967, and provide householders with an outlet for the disposal of a wide range of materials. Sites are now handling significant volumes of recyclables (66% of total household recyclables), and the transport impacts associated with increasing visitor numbers to HWRCs are of interest to traffic managers and land use planners. The transport logistics associated with servicing sites, including the collection, treatment and disposal of different materials, is complex. The reduction in landfill disposal coupled to more stringent requirements for material recycling and treatment has resulted in short journeys from HWRCs to landfill being replaced by complex road trips to different facilities at various locations. The operational, environmental and social impacts associated with these potential increases in commercial transport activities can be quantified through modelling current and projected fleet operations under various future scenarios. This can be achieved through routing and scheduling applications, which can be used to optimise transportation fleets and identify the optimal locations for waste treatment facilities. This paper provides an overview of the literature, identifying the transport arisings associated with the movement of waste to HWRCs by site users, and from HWRCs to treatment or disposal facilities by service operators. It also discusses the potential impacts on waste transportation from current and impending legislation, and the use of routing and scheduling applications to maximise commercial service vehicle operating efficiency
The use of SCOOT outputs at ROMANSE in Southampton
No full textThe ROMANSE project, initiated in 1992, established Southampton as a model for transport management systems through use of ITS. To date, the main objectives of the project have been achieved through the formation of the Traffic and Travel Information Center (TTIC). The core system in the TTIC is the SCOOT system. In turn, SCOOT outputs are being used by the PRIME and PRISCILLA projects.</p
Gauging HWRC performance from vehicle weigh-ticket data
No full textThis paper describes a modelling approach designed to investigate the variability in nett amenity bin weights produced by nine household waste recycling centres (HWRCs) in West Sussex, UK over a 12-month period. Compaction technique, vehicle type, site design and month were identified as key factors explaining 76% of the variability in the data. For each significant factor, a weighting coefficient was calculated to generate a predicted nett weight for every bin transaction. Analysis of predicted and observed mean bin weights suggested that three sites had similar characteristics but returned significantly different mean nett bin weights. Subsequent waste and site audits determined the possible sources of the remaining variability. Significant differences were identified in the proportions of bagged waste and dry recyclables deposited in the amenity waste stream at the sites, with significantly less observed at one site. Operational and managerial techniques (e.g. material separation, compaction frequency and site management ethos) were also identified as factors impacting on mean bin weights and general site performance. The model can be used to identify sites producing significantly different bin weights, enabling detailed ‘back-end’ waste analyses to be efficiently targeted and best practice in HWRC operation identifie
Estimating vehicle speed using single inductive loop detectors
No full textThis paper describes five techniques for estimating vehicle speeds using the digital output produced by a 2 m by 1.5 m single inductive loop detector sampled every 250 ms. The accuracy of each technique was then assessed on two further 2 m by 1.5 m loops fitted in single carriageways and two 2 m by 6.5 m loops spread over two carriageways. One-way ANOVA (Analysis of Variance) tests showed that there were highly significant differences between the estimation techniques in the mean deviations from the measured speeds over all four detectors during the peak period (08:00-08:50). Mean absolute percentage deviations (MAPD) from the measured speeds of between 18.8% and 47.5% were returned with an overall average of 28.4%. Settling on one technique, power regression of average loop-occupancy time per vehicle (ALOTPV) data reduced this to 22.7% based on three estimates. The poor results obtained from detector 3214KI (MAPD of 38.9%), situated immediately downstream from a signalised pedestrian crossing, indicate that estimation accuracy depends crucially on the match between the characteristics of the detector used for training and those used for testing. Despite the inaccuracies returned by some of the techniques, it was still possible to distinguish free-flow conditions and periods of queuing. The importance of estimation accuracy was not addressed
Traffic management parameters from single inductive loop detectors
No full textInvestigated are potential new uses for the digital output produced by single inductive loop detectors (2 m x 1.5 m and 2 m x 6.5 m) used in most European urban traffic control systems. Over a fixed time period, the average loop-occupancy time per vehicle (ALOTPV) for a detector being sampled every 250 ms is determined by taking the number of 250-ms occupancies and dividing by the number of vehicles. In a similar way, the average headway time between vehicles (AHTBV) is determined by taking the number of 250-ms vacancies and dividing by the number of vehicles. Over a 30-s period, the minimum and maximum values of ALOTPV and AHTBV ranged from 1 to 120 (an ALOTPV of 1 and an AHTBV of 120 representing free-flow conditions, an ALOTPV of 120 and an AHTBV of 1 representing a stationary queue). Identifying periods when a link was operating under capacity and at capacity and when it had become saturated could be more clearly identified by using plots of ALOTPV and AHTBV data over time compared to the more traditional percentage occupancy output. ALOTPV also was used to successfully identify long vehicles from cars down to speeds of 15 km/h
Journey time estimation using single inductive loop detectors on non-signalised links
Full text linkThis paper describes two techniques designed to estimate vehicle journey times on non-signalised roads, using 250 ms digital loop-occupancy data produced by single inductive loop detectors. A mechanistic and a neural network approach provided historical journey time estimates every 30 s, based on the data collected from the previous 30 s period. These 30s estimates would provide the traffic network operator with immediate post-event congestion information on roads where no close circuit television cameras were present. The mechanistic approach estimated Journey times every 30 s between pairs of detectors, using the knowledge of vehicle speed derived from the loops and the distances between them. The 30s average loop-occupancy time per vehicle, average time-gap between vehicles and percentage occupancy parameters derived from the inductive loops were presented to a neural network for training along with the associated vehicles' measured journey times. The neural network was shown to consistently out-perform the mechanistic approach (in terms of the mean absolute percentage deviation from the mean measured travel time), particularly when using pairs of detector
Remote automatic incident detection using inductive loops
Full text linkThis paper describes the remote automatic incident detection algorithm designed to detect abnormal periods of traffic congestion existing over single inductive loop detectors (typically 2 3 1.5 m). This algorithm identifies those detectors which show a critical increase in average loop-occupancy time per vehicle coinciding with a critical decrease in average time-gap between vehicles according to a set of rules previously defined by the operator. The rules define the maximum and minimum values of loop occupancy and time gap respectively for each detector, which when exceeded for a given duration, trigger a report of a potential traffic flow ‘abnormality’ for that time of day at that particular location on the network. Initial rules are developed by studying the 85th percentile values of loop occupancy returned by the urban traffic control system every 30 s. A real-time trial took place between 07:00 and 19:00 over 167 consecutive days involving 74 detectors situated along two sections of the A33 Bassett Avenue and A35 Winchester Road in Southampton. Over this period, 181and 334 triggers were recorded on the A33 and A35, respectively. An independent operator log showed that over the same period, 32 incidents were recorded on the A33 and 49 on the A35. The remote automatic incident detection system detected 69% and 92% of the verified incidents on the A33 and A35, respectively; the low detection rate on the A33 being mainly due to five incidents which occurred during off-peak periods causing no congestion and were therefore not detected
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Sustainable procurement for greener logistics in the Higher Education sector
No full textPurpose: Using the University of Southampton as a case study example, this paper reviews how procurement practices (i.e. purchasing of goods and services) of large organisations impact upon goods and service vehicle activity, with a view to investigating what approaches may be taken to reduce carbon footprint and improve environmental sustainability. The approaches considered included consolidation of suppliers, buyers (individuals and departments), orders and consignments. Research Approach: Existing procurement operating frameworks or models were initially reviewed with a view to understanding the key structures, principles, constraints and drivers that determine or influence purchasing practice. The review also considered measures that have been taken to address environmental sustainability concerns, particularly associated with goods and service vehicle activity (e.g. development of delivery and service plans). By considering both the procurement processes and the resulting generation of freight transport in tandem an improved framework can be developed to reduce freight traffic on site. Following the review, purchasing records over a period of one year from the Faculty of Engineering and the Environment at the University of Southampton were analysed to determine purchasing behaviour and to assess the volumes and frequencies of purchases made. Findings and Originality: Our preliminary analyses have illustrated the widely distributed nature of purchasing with around 250 requisitioners in a single faculty placing orders with nearly 1000 suppliers and with multiple delivery points on campus. Originality lies in the consideration of both procurement and resulting logistics activity and in the detailed analyses that are seldom undertaken by large organisations let alone published. The research builds on similar types of study undertaken at the universities of Newcastle and Westminster.Research Impact: The main research impact lies in establishing the links between procurement practices and goods and servicing activity at a large organisation, with the aim of improving environmental sustainability. Practical Impact: The study illustrates how large municipal organisations can reduce the carbon footprint associated with their purchasing activities. There is a strong practical focus to the research using purchasing records to raise awareness of purchasing behaviour and identifying practical ways to operate more sustainably. The concepts, results and conclusions are likely to be transferable to any large municipal organisation where a wide range of purchases are made by many buyers, using many different suppliers
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