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Energy and Environmental Markets
Published in Anco S. Blazev, Power Generation and the Environment, 2021
A semi-trailer truck is a large vehicle that consists of a towing engine, known as a tractor in the U.S. and truck in many other places, attached to one or more trailers. Those vehicles carry freight, also known as semi, tractor-trailer, big rig, or 18-wheeler in the United States; or transport in Canada; prime mover in Australia; and articulated lorry, or artic in the U.K.
Ro-Ro short sea shipping and Motorways of the Sea
Published in Tiago A. Santos, C. Guedes Soares, Short Sea Shipping in the Age of Sustainable Development and Information Technology, 2020
It is important to identify who takes the decision to use an intermodal transport system through Ro-Ro SSS, rather than the all-road traditional option, because it can help to determine possible actions or incentives that will encourage its use. Logistics service providers/road hauliers are, in our opinion, the key players in determining whether to use intermodal solutions in Ro-Ro SSS or MoS. In fact, Ro-Ro transport is the main focus of the MoS (Paixão and Marlow, 2007; Baindur and Viegas, 2012), which have been highlighted by the EU as part of the Trans-European Transport Network (TEN-T) and constitute the core of European policy on SSS. Using semi-trailers allows shorter delivery times, an advantage that is particularly relevant in a context of increasingly widespread just-in-time operations. As Woxenius and Bergqvist (2011) note, following Schramm (2006), the success of intermodal transport chains depends greatly on which agent acts as the coordinator and how well the operations are integrated. These authors highlight that whereas shipping companies, their agents or specialized sea forwarders take on the coordinating role in container transport, road transport firms or road-based forwarders predominate in the organization of transport chains involving semi-trailers. Douet and Cappuccilli (2011) also outline the potential of Ro-Ro SSS shipping, in a context where road hauliers are the backbone of the intermodal transport chain.
What Is Intermodal Freight Transport?
Published in Lowe FCILT David, Intermodal Freight Transport, 2006
The practice of transferring road trailers and road-borne containers onto rail wagon for trunk haulage has existed since the earliest days of rail. The hardware has obviously changed over the years and today’s domestic and international journeys are much longer than the domestic operations of yesteryear, but the basic principles remain the same. Simple wooden box containers, used even in the days of horse-drawn transport, have given way to the latest form of steel shipping container and swap body built to international (ISO) strength and dimensional standards, while road-hauled semi-trailers have developed from simple two-wheeled affairs with ‘cart-like’ springing – as drawn by the well-known railway ‘turn-on-a-sixpence’ three-wheeled Scammell mechanical horse – into high-capacity multiaxle, sophisticatedly-suspended units. In fact, present-day articulated semi-trailers are highly sophisticated pieces of equipment, cushioned with air suspension and equipped with airbrakes, and capable of safely carrying a 30-odd tonne laden ISO container or swap body within the current legal maximum vehicle gross weight limit of 44 tonnes and at the maximum permitted speed; namely 56 miles per hour (mph) for speed-limited heavy trucks. The parallel development of technically sophisticated lifting and transfer equipment enables these loading units and semi-trailers to be transferred rapidly and efficiently from road to rail or barge for long-haul transport, and back again for final delivery.
Lane-specific speed analysis in urban work zones with computer vision
Published in Traffic Injury Prevention, 2023
Yalong Pi, Nick Duffield, Amir Behzadan, Tim Lomax
With the datasets prepared, a CV-based speed measurement scheme is designed as shown in Figure 4. First, video input frames are irreversibly blurred, as shown in Figure 2 and Figure 3, to remove potential personally identifiable information (PII). After this pre-processing step, to detect vehicles (with bounding boxes), the frame is passed on to a one-stage object detection model, named YOLOv5 nano (you-only-look-once version 5 nano) (Jocher 2020), with pre-trained weights on the Microsoft COCO (common objects in context) dataset, which contains 80 common objects classes with over 328,000 images (Lin et al. 2014). These 80 classes cover a wide range of object such as laptop, horse, kite, oven, and others. In this work, the classes of interest are car and person. Other classes including bicycle and truck are excluded to avoid confusion. For example, COCO truck is defined to include concrete mixer, construction truck, semi-trailer truck and others which are rare and not differentiated. The midpoint pixel coordinates of the lower edge of each bounding box (black rectangles in Figures 2 and 3) are then taken as the location of the vehicle. The main reason for choosing YOLOv5 nano is its small size (about 75% fewer parameters, down from 7.5 million to 1.9 million), allowing it to process images in real-time on a consumer-grade processor (in this research, Intel i9 CPU only), thus making it an ideal choice for mobile solutions. Besides, the model can achieve a mean average precision (mAP) of 70% on the COCO test dataset which surpasses other CNN models such as Faster RCNN (Ren et al. 2015) and RetinaNet (Lin et al. 2017).
Analysis of a moving measurement platform based on line profile sensors for project-level pavement evaluation
Published in Road Materials and Pavement Design, 2021
Asmus Skar, Eyal Levenberg, Sebastian Andersen, Mathias B. Andersen
The Raptor device is a semi-trailer truck equipped (at the rear) with two independent single-wheel suspension systems – one on each side. Its sensor beam is installed in an environmentally protected compartment at the bottom of the platform, approximately 200 mm above the pavement surface, passing close to one of the tires (from the inner side); it carries an array of laser-based line profilers. Figure 1 shows a sketch of the Raptor measurement trailer and truck with a sensor beam carrying I lasers (i = 1..I) arranged such that Laser I is the forwardmost laser and Laser 1 is the rearmost laser. The forces in the figure represent static axle loads with V denoting the travel speed. A plan view of the platform is offered in Figure 1(a) and a side view is shown in Figure 1(b). The designation kN is used as there is no connection between the rear wheels. The shape of the deformed pavement surface for a cross-section taken directly below the sensor beam (i.e. along x with y = 0) is also sketched in Figure 1(b). This sketch was prepared to provide intuition on the expected laser readings; it is based on a linear elastic half-space.
Failure mode and effects analysis of dual levelling valve airspring suspensions on truck dynamics
Published in Vehicle System Dynamics, 2019
Yang Chen, Yunbo Hou, Andrew Peterson, Mehdi Ahmadian
The potential failure modes and their effects for truck pneumatic suspensions were simulated and studied. Three representative failure cases were selected for the study: (1) fully blocked levelling valve, (2) bent control rod and (3) air leakage in pipes and connecters due to puncture, wear or damage during use. A multi-domain model that includes fluid dynamics of detailed pneumatic suspensions, semi-trailer truck dynamics and the effect of the suspension failure was developed. The suspension dynamic response and vehicle body roll for a suspension with dual levelling valves – referred to as ‘balanced air’ or ‘BA’ suspension – was computed for a designed steer input. The results were compared with a suspension with a single levelling valve – referred to as ‘OE’ suspension – for each failure case. The results overwhelmingly suggest that for the BA suspension the failure on one side of the suspension has a minimal effect on the roll dynamics of the vehicle, due to the failure redundancy offered by two levelling valves. The un-failed side works to keep the tractor body levelled in case of any suspension failures considered in this study. Interestingly, the study also indicates that the trailer suspensions further help with maintaining the body levelled, particularly when the trailer is also equipped with BA suspensions. In addition, in the event of air leakage, the BA suspension exhibited a better ability to maintain the vehicle ride height.