Speed Camera Research Articles

Bicycle safety outside the crosswalks: Investigating cyclists' risky street-crossing behavior and its relationship with built environment

Most bicycle accidents are inextricably bound up with risky riding behaviors, which crossing the street illegally at unprotected mid-block locations is nothing to sneeze at. Compared with cyclists crossing the street at the crosswalk or intersections, there is a huge risk of accidents when they ignore or disobey road rules and across recklessly. Yet, the misbehavior of cyclists is an under-explored area in cyclist research due to the limited availability of detailed cycling data. This study creatively develops a GPS-based detection framework to capture risky street-crossing actions for the cyclists from large-scale bike sharing trajectory data. A data-driven modeling approach, based on structural topic modeling (STM), is developed to reveal the complexity and regularity of cyclists' habitual risky crossing behavior. Since objective built environment is one of the key factors associated with cycling, another goal of this paper is to apply a gradient boosting decision tree (GBDT) model to disentangle how the features of built environment may influence the frequency of risky crossing events. The case study results show that risky street-crossing behavior is prevalent in bicycle traffic – for example, 16.94% of cycling trips are involved in illegal crossing action. Most cyclists engage in illegal crossing behavior at the approximate central part of the streets and during the day, which reveals the presence of heterogeneity over space and time. Strong correlations between commuting activities and risky street-crossing behaviors are identified from topic modeling. Meanwhile, the latent illegal crossing patterns unraveled here highlight that typical reasons for committing the risky riding action include the lure of the travel destination across the road and the inconvenience of riding round in distant legal crossing facilities. GBDT findings provide new insights on the existence of the association between built environment and cyclists' illegal crossing action. The places related employment and catering play a dominant role in contributing risky street-crossing behavior, and the influences of road length, road level, bus stop and metro station are not neglectable. Most built environment attributes show nonlinear correlations with crossing frequency. It is anticipated that this study would successfully shed a first light on the pattern of cyclists' risky street-crossing behavior at the metropolitan scale, and compliment engineering practices to improve crossing behaviors and bicycle safety.

Swirl Effects On Gas-Liquid Upward Vertical Pipe Flow

Abstract When swirl is added to gas-liquid upward vertical pipe flows (e.g. inside an inline swirl separator), the classical flow patterns are modified by the centrifugal forces which act pushing the gas towards the center of the pipe and the liquid towards the wall. If the swirl is strong enough, this leads to the formation of a gas column in the center of the pipe, which can be either stable or intermittent. It was observed experimentally that the behavior of the gas column is strongly dependent on the dynamics of the gas-liquid flow upstream of the addition of swirl. In this video, a high speed camera was used to record the gas-liquid flow upstream and downstream of a swirl-generating element for different flow rates of liquid and gas, covering multiple non-swirling (upstream) and swirling flow patterns (downstream). The video: (i) shows the different swirling gas-liquid flow patterns and their dynamic behavior; (ii) analyzes the connection between the dynamics of the swirl patterns and the gas-liquid patterns upstream of the swirl element, via synchronized recordings of the two locations.

Experimental Research on Ignition Process of a Supersonic Combustor Based on a Strut Fueled with Liquid Kerosene

The ignition process in a thin strut equipped supersonic combustor fueled with liquid kerosene was observed to deepen the understanding of the ignition characteristics. A large number of experiments were carried out under the conditions of Tt=1,680 K, Pt=1.87 MPa, and Ma=2.8. The combustion establishment process and the flame characteristics were captured and reproduced by a high speed camera. Results show that the flame is first established near the igniter flame in the lower half of the combustor under the action of the recirculation zone and oxygen supplement at the end of the strut. Then, the flame spreads to the main flow of the combustor. The ignition process under different equivalence ratios was compared and studied. The results indicate that the ignition delay time and the flame distribution of the ignition process are affected by the equivalence ratio. At the same time, it was found that there are two modes in the flame establishment process, namely, the upstream propagation mode and the downstream propagation mode. The flame propagation speeds in different directions under these two propagation modes are different. The results presented in this paper are valuable for the future optimization of ignition performance in a scramjet combustor using kerosene fuel injection.

Air Pocket Expulsion from a Submerged Dropshaft with Inflow

Entrapped air pockets reduce flood conveying capacity of a surcharged drainage tunnel, and could be released explosively as geysers from vertical dropshafts. Nevertheless, the impact of dropshaft inflow on air pocket expulsion has hitherto not been fully understood. In this work, experiments was performed on a simplified drainage system consisting of a dropshaft with inflow. An air pocket was introduced into the tunnel; its dynamics in the dropshaft was measured with a high speed camera and pressure transducers. A heuristic analysis on the kinematics of the air pocket showed that when the dropshaft inflow is greater than a critical flow dependent on the dropshaft diameter, the increased compression leads to stronger air pocket expulsion, as spewing and/or ejection of air-water mixture. Observed occurrence of the phenomena generally agrees with the prediction.

Optimization of Mirror Positioning for Single‐Camera 3D Displacement Measurements

AbstractCamera‐based 3D displacement measurements are only possible when two different viewing angles of the respective measurement point are available. We earlier introduced a simplified 3D reconstruction algorithm for camera‐mirror measurements where the mirror reflects the second view onto the camera sensor to eliminate the need for a second (costly) high speed camera. In this study, we concentrate on formulating guidelines on how to position the mirror with respect to the camera and the measured structure, the goal being to minimize errors arising in the 3D reconstruction procedure. The focus lies on the angle between the optical axes of both camera views. We hereby also take into account limitations in the experimental setup that the special camera‐mirror‐setup brings with it. This study is conducted in terms of simulations using the animation software BLENDER as well as real experiments on a simple vibrating structure.

ITSS: An Intelligent Traffic Signaling System Based on an IoT Infrastructure

Recently, there has been a huge spike in the number of automobiles in the urban areas of many countries, particularly in India. The number of vehicles are increasing rapidly and with the existing infrastructure, the traffic systems stand still during peak hours. Some of the main challenges for traffic management are the movement of overloaded vehicles beyond their restricted zone and time, reckless driving, and overlooking road safety rules. This paper proposes an Internet of Things (IoT)-based real-time Intelligent Traffic Signal System (ITSS), which consists of inductive loops and a programmable micro-controller to determine traffic density. Inter-communication in the centralized control unit sets the timer of the traffic light and synchronizes with the traffic density in real-time for smooth mobility of vehicles with less delay. Additionally, to prioritize emergency vehicles over other vehicles in the same lane, a pre-emption mechanism has been integrated through infrared sensors. The result of traffic density determines the timer of the light post in real-time, which in result enhances the smooth flow of vehicles with reduced delay for travelers. Using its automatic on-demand traffic signaling system, the presented solution has advantages over fixed systems.

Survey of Innovative Techniques for Speed Measurement of Vehicles

Advanced technology offers various alternatives for the speed measurement of vehicles. However, different technologies often result in different accuracy in the speed measurement of the vehicle. Lack of knowledge of accuracy between different technologies is a common problem for the researcher. This paper discusses the different techniques for speed measurement of vehicle-based on the theoretical study. One of the primary reasons for measuring speed is to enforce traffic speed laws and promote road safety. Speed limits are set to ensure that vehicles are travelling at safe speeds, given the conditions of the road, weather, and traffic. The use of speed measuring devices such as radar guns, laser guns, and speed cameras allows law enforcement agencies to monitor traffic and identify vehicles that are exceeding the speed limit. This information can then be used to issue citations or warnings to drivers, and ultimately to reduce the number of speed-related accidents and improve road safety. Various speed measurement techniques are included such as. RADAR (Radio Detection and Ranging) - this is one of the most common speed measurement techniques and uses radio waves to determine the speed of a vehicle, GPS (Global Positioning System) - GPS uses satellite technology to determine the location and speed of a vehicle. The MIRROR system uses multiple radar units to determine the speed of a vehicle, LIDAR (Light Detection and Ranging) - this technique gauges a vehicle's speed using lasers. The Speed Detection Camera System (SDCS) measures a vehicle's speed using cameras and image processing methods. On the highway, video streams are employed in image processing techniques to calculate the speed of the car.

The Emergence of Specialized Roles Within Groups.

Humans routinely form groups to achieve goals that no individual can accomplish alone. Group coordination often brings to mind synchrony and alignment, where all individuals do the same thing (e.g., driving on the right side of the road, marching in lockstep, or playing musical instruments on a regular beat). Yet, effective coordination also typically involves differentiation, where specialized roles emerge for different members (e.g., prep stations in a kitchen or positions on an athletic team). Role specialization poses a challenge for computational models of group coordination, which have largely focused on achieving synchrony. Here, we present the CARMI framework, which characterizes role specialization processes in terms of five core features that we hope will help guide future model development: Communication, Adaptation to feedback, Repulsion, Multi-level planning, and Intention modeling. Although there are many paths to role formation, we suggest that roles emerge when each agent in a group dynamically allocates their behavior toward a shared goal to complement what they expect others to do. In other words, coordination concerns beliefs (who will do what) rather than simple actions. We describe three related experimental paradigms-"Group Binary Search," "Battles of the Exes," and "Find the Unicorn"-that we have used to study differentiation processes in the lab, each emphasizing different aspects of the CARMI framework.

Investigating bouncing water droplets with high speed cameras

Results determined the upper limit for the impact velocity of bouncing droplets on micro-grooved surfaces.

Comparison Between Daytime, Twilight and Nighttime on Detection of Approaching Vehicles by Pedestrians

This study examined the causes of traffic accidents between pedestrians and vehicles at twilight, based on the visual characteristics of pedestrians at twilight. To obtain data on the visual characteristics of pedestrians, we conducted an experiment in which a participant wearing an eye tracker walked along a sidewalk on the right side of the road passing vehicles during the daytime, twilight, and nighttime. The experimental data were analyzed by dividing the visual objects into static and dynamic ones. The results showed that the visual characteristics at twilight were not intermediate between those at daytime and nighttime, but were particular ones. It was also revealed that at twilight, people tend to neglect looking carefully at dynamic objects, and the timing of looking at the dynamic objects is apt to be limited to a specific distance.

Atomization characteristics of different water/heavy fuel oil emulsions in a pressure-swirl injector

In the present study, different water in heavy fuel oil (HFO) emulsion fuels containing 5, 10, 15% water content have been prepared under ultrasound irradiation without surfactant. The stability of the prepared emulsion fuels has been investigated. The best stability was observed for the emulsion fuel containing 5% water (E5) due to its more uniform water droplet size distribution. Then, the atomization behavior and spray characteristics of the emulsion fuels have been investigated in a pressure-swirl injector using a high speed camera. The examined ranges for temperature and pressure were (60–110 °C), and (10–25 bar), respectively. The breakup length for each fuel sample in each operating condition was calculated through the image processing analysis. It was found that the micro explosion phenomena associated with the evaporation of the water droplets in the fuels has the most impact on the emulsion fuel spray characteristics. The best atomization performance was observed for E5 considering all examined fuel samples. A 68% decrease in the breakup length was observed for E5 compared to the neat HFO at 90 °C and 15 bar.

Parameterization and Design of Telepresence Robot to Avoid Obstacles

Background: The development of telepresence robots is getting much attention in various areas of human–robot interaction, healthcare systems and military applications because of multiple advantages such as safety improvement, lower energy and fuel consumption, exploitation of road networks, reduced traffic congestion and greater mobility. Methods: In the critical decision-making process during the motion of a robot, intelligent motion planning takes an important and challenging role. It includes obstacle avoidance, searching for the safest path to follow, generating appropriate behavior and comfortable trajectory generation by optimization while keeping road boundaries and traffic rules as important concerns. Results: This paper presents a state machine algorithm for avoiding obstacles and speed control design to a cognitive architecture named auto-MERLIN. This research empirically tested the proposed solutions by providing implementation details and diagrams for establishing the path planning and obstacle tests. Conclusions: The results validate the usability of our approach and show auto-MERLIN as a ready robot for short- and long-term tasks, showing better results than using a default system, particularly when deployed in highly interactive scenarios. The stable speed control of the auto-MERLIN in case of detecting any obstacle was shown.

Experimental study on effect of surfactant and solution property on bubble rising motion

Bubbly flows are frequently run into in industrial processes. Since liquid phases usually contain impurities, bubble interface is polluted to a certain degree. This can affect flow structures, and heat and mass transfer properties at bubble interface, leading to a significant effect on industrial efficiencies. Therefore, it is important to study the hydrodynamic characteristics of polluted bubbles. It was experimentally investigated on the effects of surfactant concentration, ionization and solvent polarity on bubble shape, rise trajectory and velocity using a high–speed camera in this paper. The present studies show that the addition of a very small amount of non–ionic surfactants (1–OA) into a polar solution (a 56% glycerol–water solution) can cause a great change in bubble rise trajectory (an inhibition of about 80% in bubble lateral migration) and a decrease in bubble rise velocity (a decrease of about 25% in bubble maximum velocity) because surfactant molecules adsorbed at bubble interface gather tightly. However, the addition of ionic surfactant (SDS) with the same concentration into a polar solution cannot cause a significant change in bubble rise trajectory and rise velocity because the distribution of surfactant molecules adsorbed at bubble interface is relatively loose due to an electrostatic effect. The addition of surfactants into a non–polar solution (Dimethyl silicone oil) cannot obviously change the above parameters due to the non–solvent effect of surfactants in non–polar solutions. Namely, surfactant molecules cannot be adsorbed at bubble interface.

Integrated Graphical Representation of Highway Scenarios to Improve Trajectory Prediction of Surrounding Vehicles

Varying numbers and types of vehicles, various road structures and traffic rules bring difficulties to an autonomous vehicle driving in highway traffic scenarios. It is important to simultaneously consider all these elements in an integrated framework when predicting the future trajectories of surrounding vehicles. This paper presents a unified graphical representation method for dynamic traffic scenarios based on integrating not only the constraints from vehicles but also the collision risk implied behind road structures and traffic rules. Different from previous studies which ignores road structures and traffic rules or separately represent them in a qualitative way, this method can make better use of the influences of these environment elements in a quantitative way to improve trajectory prediction of surrounding vehicles in highway scenarios. Specifically, this method first assesses the permissibility and passability of different types of roads and vehicles, and then defines their collision risk level based on traffic rules like speed limit or priority signs. Secondly, the bird-view scenarios are rasterized and rendered as color-scaled feature maps based on this risk level. Finally, multiple feature maps with various spatial and temporal perspective field are sequentially fed to a convolutional long short-term memory (LSTM) network to predict trajectories for surrounding vehicles. We implement the model on NGSIM dataset and achieve satisfying prediction accuracy, for example, the error over 5s time prediction horizon can be reduced to less than 2.78m in longitudinal and 0.26m in lateral direction.

Investigating distance halo effect of fixed automated speed camera based on taxi GPS trajectory data

Investigating distance halo effect of fixed automated speed camera based on taxi GPS trajectory data

External and internal influences on mobile phone use while driving: Combining the theories of deterrence and self-determination

ObjectivesVarious legal countermeasures have been introduced in numerous jurisdictions worldwide to reduce the risky behaviour of phone use while driving. However, external factors do not influence behaviour alone; internal factors may also play a large role in influencing behaviour. Therefore, the aim of this study was to examine the impact of both external and internal influences on hand-held phone use while driving. Methods and analysisThe influence of external factors was examined after a higher penalty and a trial for mobile phone detection cameras was introduced in Queensland, Australia, utilising deterrence-theory related constructs. Meanwhile, internal factors were examined through the lens of self-determination theory to determine the relevance of self-regulation to phone use while driving, over and above the effect of deterrence factors. FindingsA total of 866 participants (M age = 37.51 years, SD = 17.23) completed a survey examining these variables. Despite the changes to the penalty and enforcement, the legal factors did not significantly deter drivers from phone use while driving. Instead, participants reported avoiding punishment, which influenced further engagement in the behaviour. Meanwhile, indicators of self-regulation including effort/importance, perceived pressure, and relatedness were found to have a more salient impact on the behaviour, whereby drivers who reported high levels of internalised regulatory processes were less likely to use a hand-held phone while driving. Novelty and improvementThese results provide a novel contribution to understanding road rule compliance and have important implications for both theory and practice. For example, it can be suggested that legal countermeasures need to be improved, while non-legal countermeasures that target internalisation is a promising avenue for future research.

Design and development of a digital intervention for crime prevention: a road safety intervention targeting young driver non-compliance

PurposeThis purpose of this study is to outline an inclusive development strategy for crime prevention interventions. Crime prevention interventions are delivered to the target audience to convey an evidence-based message to dissuade would-be offenders from carrying out crimes. However, rarely is the target audience involved when designing crime prevention interventions.Design/methodology/approachUsing the Delphi method, this paper documents the design of an intervention aimed at improving young drivers’ compliance with road rules, incorporating feedback from both a panel of experts and the target audience of the intervention. While expert feedback guided the content and the context of the intervention, the feedback from the target audience was critical in ensuring that effective delivery and messaging of the crafted intervention would occur.FindingsBy drawing on expert and experiential insights, this exploratory method of intervention design provided a simple and effective way of ensuring the effective delivery of a crime prevention message.Research limitations/implicationsAlthough this study focussed on a road safety intervention, the crime prevention applications of this method are broad.Originality/valueThis paper outlines a collaborative methodology that utilises expert and experiential knowledge towards the design and development of a crime prevention intervention, in this case, targeted at young drivers.

What leads underage teenagers to ride motorcycles without a permit? Utility vs parental permissiveness

ObjectivesIllegal motorcycle riding among teenagers often results in crashes and disastrous consequences; however, it is rampant in many low and middle-income countries. This article seeks to elucidate the factors that lead to this behaviour, and why parents permit it. MethodsThe study relies on a survey of 832 parents of adolescents (16 to 18 years old) in Ho Chi Minh City, Vietnam. These data are modelled based on a new conceptual framework which combines elements of the Technology Acceptance Model, the Theory of Planned Behaviour, and the Focus Theory of Normative Conduct with a few tailored constructs and four relevant control variables (age, gender, income, and home-school distance). The underlying latent factors were derived through Exploratory Factor Analysis (EFA). Subsequently, binary logit regression and ordinal logit regression were applied to model the illegal use of motorcycles and the parental intention to permit this behaviour. ResultsWe find that 61% of teenagers – older boys from wealthier families in particular – use motorcycles illegally. They do so because their parents see motorcycles as useful and easy to use. Besides, parents enable unpermitted riding because it is socially acceptable to do so, and that is what teens prefer. A perception of weak road rule enforcement is another facilitator while perceived crash risk is an impediment. ConclusionsInterventions and solutions to prevent the illegal use of motorcycle are necessary. The goal is to improve safety rather than penalize teens for using motorcycles. A reasonable and effective approach would be to change the law to allow teenagers as young as 16 to ride motorcycles – but only after a period of rigorous training and testing to ensure safety.

In-situ quality monitoring of laser hot wire cladding process based on multi-sensing diagnosis and machine learning model

This study aimed to build an in-situ monitoring system based on a multi-sensing diagnosis strategy combined with a machine learning model for laser hot wire cladding applications. A high speed camera and spectrometer were mounted to obtain in situ synchronization information. Eight process signal features were extracted based on the molten pool and plasma. The silica brittle inclusions result in a higher, narrower, and rougher clad layer with higher and more uneven hardness than the normal clad layer and eventually caused undercut defects. Three quality features based on a seam tracker based surface profiling technique were extracted to label the process signal features, and an empirical database was produced based on the quantified experimental results. The minimum redundancy maximum relevance algorithm was then used to rank the importance of the process signal features, through which, a new feature vector was created. Finally, the eXtreme gradient boosting (XGBoost) model was used to develop an in-situ monitoring system for the laser hot wire cladding process. This MRMR-XGBoost based system reduces the redundancy of process information and achieved the cladding quality classification with an accuracy of 0.9727 and identify time of 7.979 ms.

A laboratory platform for studying rotational dust flows in a plasma crystal irradiated by a 10 keV electron beam

A novel laboratory platform has been designed and built for the irradiation of a plasma crystal (PC) with an electron beam (e-beam) having an energy around 10 keV and a current of tens of milliamperes. The pulsed e-beam collimated to a few millimeter-size spot is aimed at a crystal made of dust particles levitated in a radio-frequency (RF) plasma. The platform consists of three vacuum chambers connected in-line, each with different utility: one for generating free electrons in a pulsed hollow-anode Penning discharge, another for the extraction and acceleration of electrons at sim 10 kV and for focusing the e-beam in the magnetic field of a pair of circular coils, and the last one for producing PCs above a RF-driven electrode. The main challenge is to obtain both a stable e-beam and PC by insuring appropriate gas pressures, given that the e-beam is formed in high vacuum (lesssim 10^{-4} Torr), while the PC is produced at much higher pressures (gtrsim 10^{-1} Torr). The main diagnostics include a high speed camera, a Faraday cup and a Langmuir probe. Two applications concerned with the creation of a pair of dust flow vortices and the rotation of a PC by the drag force of the e-beam acting on the strongly coupled dust particles are presented. The dust flow can become turbulent as demonstrated by the energy spectrum, featuring vortices at different space scales.