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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluating the Impact of Double-Parked Freight Deliveries on Signalized Arterial Control Delay Using Analytical Models and Simulation

Keegan, Aaron J. 25 October 2018 (has links)
Freight deliveries on signalized urban streets are known to cause lane blockages during delivery. Traffic congestion associated with urban freight deliveries has gained increasing attention recently as traffic engineers and planners are tasked with finding solutions to manage increasing demand more sustainably with limited road capacity. The goal of this research is to evaluate two models for quantifying the capacity and signalized control delay effects of a lane-blocking freight delivery on an urban arterial. The two methods are: an All-or-Nothing model similar to methodology used in the Highway Capacity Manual 6th Edition, and a Detailed model consistent with kinematic wave theory. The purpose is to provide insight on the use of these tools for analysis of urban freight delivery. The signalized control delay results of the two models are compared with observed video data of urban deliveries from one city block of 8th Ave in New York City. Empirical confirmation of double-parked delivery impact on signalized controlled delay remains elusive due to an inability to isolate the effects of the deliveries from other traffic perturbations in the video sample. Instead, microscopic simulation using Aimsun is used for comparison to the theoretical models and the results lend credibility to the Detailed model. The simulation results show a similar trend of delay impact from double-parked deliveries located at a range distances from the intersection and more closely resembled the Detailed model. The All-or-Nothing model would provide only a coarse representation of the capacity and delay effects. The more detailed approach that accounts for the dynamics of queuing in front of the delivery vehicle provides closed form analytical formulas for capacity and signalized control delay that can account for varying locations of deliveries as well as analysis periods with some blocked cycles and others unblocked. Two policy implications are proposed: 1) that double-parked deliveries located mid-block likely result in less signalized control delay impact, and 2) freight receivers that attract double-parked deliveries near an intersection stop line should be prioritized in urban freight delivery mitigation policies such as off-hour delivery.
2

Creating Value from Last Mile Deliveries to First Mile Recycling : A Case Study of an Urban Consolidation Center / Skapa Värde från Urbana Varuleveranser till Urban Avfallshämtning : En Fallstudie av en Urban Samlastningscentral

WESTERLUND, GUSTAV, BABAN, DARIN January 2021 (has links)
This study is a part of the HITS-project at the Integrated Transport Research Lab at KTH. The demand for urban freight transportation has continued to grow during the last decades due to increased urbanization. Road-based freight transport contributes to air pollution, traffic congestion and noise pollution. The dependency of these services and because of their emissions of greenhouse gases there is a need for new sustainable initiatives.  To investigate the possibility of consolidating the delivery of parcels and collection of recycling materials, a pilot initiative called Älskade Stad has been implemented in Stockholm. Traditionally, similar initiatives have encountered problems when municipalities have stopped the funding and it has also been difficult to convince companies to cooperate. Therefore, the aim of this study is to investigate what values that are being created from an urban consolidation center (UCC), as these could be seen as incentives for joining. Furthermore, it will identify what value propositions that are being offered for the city and the involved companies and how these companies capture these values.  The thesis is conducted as a qualitative case study and uses the business model approach as a conceptual framework. The result from the study shows that four key resources and activities were related to value creation: a smaller truck which increased the filling rates, exemptions received from the municipality, new garage space utilization, and goods and waste flow consolidation. Furthermore, sustainable value propositions are offered to the companies and the city, such as, more attractive streets, higher profitability on trucks, increased publicity, improved work environment and finally green transportation solutions. This has entailed changes to the value capturing for the involved companies. Changes that are related to savings, revenue, and cost streams. The analysis from the study showed that the implementation of an UCC can help the city when facing urbanization challenges, and lead to a cleaner, safer, and more attractive city. / Denna studie är en del av HITS-projektet vid Integrated Transport Research Lab vid KTH. Efterfrågan på urbana varutransporter har fortsatt att öka under de senaste årtiondena på grund av en ökad urbanisering. Vägbaserad varutransport bidrar till luftföroreningar, köbildning och ljudföroreningar. Vikten av dess tjänster i kombination med dess stora utsläpp av växthusgaser skapar ett behov av nya hållbara initiativ.  För att utforska en lösning som konsoliderar varuleveranser och upphämtning av returmaterial, har en pilotstudie med namnet Älskade Stad genomförts i Stockholm. Historiskt sett har liknande initiativ mött problem när finansiering från offentlig sektor tagit slut och dessutom har det varit svårt att övertyga företag att delta i samarbeten. Därför ämnar denna studie att kartlägga vilka värden som faktiskt skapas med hjälp av en urban samlastningscentral, vilket skulle kunna ses som möjliga incitament. Vidare syftar denna studie till att kartlägga vilka värden som erbjuds för staden samt involverade företag och hur dessa värden fångas av företagen.  Denna uppsats är genomförd i form av en kvalitativ fallstudie och använder ett affärsmodellsperspektiv som teoretiskt ramverk. Genom semistrukturerade intervjuer med experter som är involverade i initiativet samt forskare insamlades data. Resultaten från studien påvisar fyra huvudsakliga aktiviteter och resurser kopplat till värdeskapande: en mindre lastbil som ökade fyllnadsgraden, dispenser utdelat från stadsförvaltningen, ny garageanvändning samt godskonsolidering. Utöver detta så uppstår ett hållbart värdeerbjudande till företagen och staden i form av en mer attraktiv gatumiljö, högre lönsamhet på sopbilar, ökad publicitet, förbättrad arbetsmiljö och en grön transportlösning. Detta har medfört förändringar när det gäller företagens värdefångst, förändringar kopplade till besparingar, intäkts- och kostnadsflöden. Analysen från studien visat att en implementering av en urban samlastningscentral kan hjälpa staden att bemöta urbaniseringsutmaningar och bidra till en renare, säkrare och attraktivare stadsmiljö.

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