scholarly journals Raised Pedestrian Crossings: Analysis of Their Characteristics on a Road Network and Geometric Sizing Proposal

2019 ◽  
Vol 9 (14) ◽  
pp. 2844 ◽  
Author(s):  
Loprencipe ◽  
Moretti ◽  
Pantuso ◽  
Banfi
Keyword(s):  
Urban Areas ◽  
Ride Comfort ◽  
International Standards ◽  
Motor Vehicles ◽  
Whole Body ◽  
Vehicle Speed ◽  
Traffic Calming ◽  
Dynamic Performances ◽  
Vertical Accelerations ◽  
Pedestrian Crossing

In urban areas traffic-calming strategies and pedestrian friendly measures are often adopted to reduce the adverse impacts of motor vehicles on vulnerable users. This study surveyed 24 raised pedestrian crossings (RPCs) to examine their geometrical and functional characteristics. Geometric characteristics, location, administrative and effective vehicle speed, and the whole-body vibration acceleration induced to vehicle occupants while they are passing over, were considered. In addition to the analysis of the field data, geometrical and functional criteria to design RPCs were carried out. Particularly, two design approaches have been considered. In the first one, RPC provides a designated route across a carriageway raised to the same level, or close to the same level, as the sidewalks that provide access to the pedestrian crossing. In such condition, an RPC is not a traffic-calming device and its design should satisfy geometrical and comfort criteria for designing roads. The results from the surveys demonstrated that less than 10% of RPCs guarantee ride comfort. According to the second design approach, an RPC acts both as a marked pedestrian feature and as a traffic-calming device (i.e., it is trapezoidal in shape with sharp edges). The analysis of the vertical accelerations on vehicle occupants reveal that more than 90% of the surveyed RPCs comply with geometrical and dynamic criteria for speed tables. Extreme variations concerning the observed geometrical characteristics of RPCs and the modelled dynamic performances have been observed: It results in noneffective treatments. Therefore, the results of this study would contribute to providing geometric best practices for overcoming the regulation gap in this subject, and designing RPCs according to international standards.

scholarly journals Urban School Area Road Safety Improvement and Assessment with a 3D Piano-Keyboard-Styled Pedestrian Crossing Approach: A Case Study of Chiang Mai University Demonstration School

2020 ◽  
Vol 12 (16) ◽  
pp. 6464
Author(s):  
Preda Pichayapan ◽  
Manop Kaewmoracharoen ◽  
Thanatchaporn Peansara ◽  
Patcharapan Nanthavisit
Keyword(s):  
Traffic Accidents ◽  
Three Dimensional ◽  
World Health ◽  
P Value ◽  
Vehicle Speed ◽  
Significance Level ◽  
Traffic Calming ◽  
Safety Improvement ◽  
The World ◽  
Pedestrian Crossing

Traffic accidents are a major cause of death in Thailand. Thailand is ranked third in the world by the World Health Organization for traffic-related deaths. Decreasing road accidents is one of the Thailand National Strategy Goals and also the United Nations Sustainable Development Goals. Several traffic calming tools for school areas were reviewed for safety improvement. An approach of creating a three-dimensional piano-keyboard-styled pedestrian crossing was implemented. It used a one-point perspective technique to increase driver perception when approaching a pedestrian crossing. The assessment data were observed during 12 weeks of a school semester. A roadside camera was used to record vehicles during the morning peak, midday off-peak, and evening peak traffic. The vehicles’ average speeds were used to compare the pre- and post-installation safety. The results showed that after the new crossing was installed, vehicle speeds drastically decreased. After three weeks, vehicle speeds began to increase. After twelve weeks, the vehicle speeds had gradually increased toward the same level as before the installation. A z-test was performed at the 95% significance level (p-value 0.05), showing that the new crossing approach had only affected vehicle speed during the first three weeks post-installation. Driver familiarity behavior and faded paint were major factors in the results.

Experimental Assessment of the Ride Comfort of Farm Tractors

2013 ◽  
Author(s):  
Stefano Dominoni ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu ◽  
Giorgio Previati
Keyword(s):  
Ride Comfort ◽  
The Body ◽  
Whole Body ◽  
Huge Number ◽  
Comfort Index ◽  
Proper Comparison ◽  
Vertical Accelerations ◽  
The Time Domain ◽  
Iso 2631 ◽  
Whole Body Vibrations

The paper is focused on the assessment of the ride comfort of that farm tractors. The problem of assessing the ride comfort is crucial due to the fact that operators spend part of their own lives on board of such machines, exposed to whole body vibrations potentially harmful for their health. The paper deals with the experimental measurement of the relevant vibration occurring at the tractor body, at the cabin and at the seat. The focus is on which accelerations are actually relevant and have to be taken into account. A number of farm tractors have been instrumented and run under monitored conditions. The test track was equipped with a number of cleats able to force at resonance the cabin and the seat. The six motions of the tractor body and the six motions of the cabin were measured. The motion of the seat was measured. The signals have been processed in the time domain. Some interesting occurrence have been highlighted referring to the amplification that a badly regulated seat can provide under certain circumstances. The comfort index was computed according with ISO 2631 and other standards. The acceleration of the seated subject was described at different positions on the body. It turned out that the acceleration of the head was particularly relevant for establishing a comparison among different tractors. Synthetic indices have been derived from the measured data able to correlate the subjective drivers’ feeling with the measured level of vibration. The conclusion is that for a proper comparison of the ride performance of different farm tractors a huge number of measurements are needed. There is no possibility to record only the vertical accelerations to assess the ride comfort of farm tractors.

scholarly journals The Effect of Brick and Granite Block Paving Materials on Traffic Speed

2019 ◽  
Vol 16 (19) ◽  
pp. 3704 ◽  
Author(s):  
Xavier Rojas Nogueira ◽  
Jeremy Mennis
Keyword(s):  
Urban Areas ◽  
Fixed Effects ◽  
Matched Pair ◽  
Vehicle Speed ◽  
Automobile Accidents ◽  
Traffic Calming ◽  
Road Roughness ◽  
Asphalt Paving ◽  
Traffic Speed ◽  
Negative Health Outcomes

Slowing traffic speed in urban areas has been shown to reduce pedestrian injuries and fatalities due to automobile accidents. This research aims to measure how brick and granite block paving materials, which were widely used historically prior to the use of asphalt paving in many cities, may influence free flow traffic speed. Traffic speeds for 690 vehicles traversing street blocks paved with asphalt, granite block, and brick materials were measured using a radar gun on a sample of 18 matched pair (asphalt and historic paving material) street blocks in Philadelphia, Pennsylvania. Fixed effects linear regression was used to estimate the effect of paving material on vehicle speed after controlling for the street class (e.g., arterial versus local road) and the matched pair. Results indicate that brick reduced speeds by approximately 3 mph (~5 km/h) and granite block reduced speeds by approximately 7 mph (~11 km/h), as compared to asphalt paved city streets, which we attribute to drivers intentionally slowing due to road roughness. This research suggests that brick and granite block paving materials may be an effective traffic calming strategy, having implications for reducing negative health outcomes associated with pedestrian–automobile collisions.

Ride Comfort of Urban Minibus Driver through Optimization of Seating Parameters and Vehicle Speed

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
M.Jaganmohan Rao ◽  
S.P. Sivaprakasam ◽  
G. Yan Arora
Keyword(s):  
Genetic Algorithms ◽  
Orthogonal Array ◽  
Ride Comfort ◽  
Whole Body ◽  
Vehicle Speed ◽  
Horizontal Distance ◽  
Analysis Process ◽  
Comfort Levels ◽  
The City ◽  
Seat Inclination

The current research details the urban minibus drivers comfort levels. These buses are used for shuttle services within the city as well as school services. Long seating is a vibrant risk factor for back pain for minibus driver’s exposed to whole body vibration (WBV). In this paper, effects of seat inclination, speed and seat distance from the ABC pedal on seat acceleration are investigated by the statistical methods of analysis of variance (ANOVA), Taguchi’s orthogonal array, regression analysis. Process parameters are prioritized by Taguchi’s L27 orthogonal array. ANOVA determines the significance and percentage contribution of each parameter. Seat inclination has a greater contribution on ride comfort followed by the speed and seat horizontal distance. To optimize the human comfort vibration in minibus, genetic algorithms and multiple regression models were used. The values predicted from experimental, regression model and genetic algorithms values are found to be in good correlation.

Profile Optimization of Table Top Speed Hump for Speed Control

2011 ◽  
Author(s):  
Theunis R. Botha ◽  
Pieter S. Els ◽  
Petronella E. Uys ◽  
Rudolf Bester
Keyword(s):  
Urban Areas ◽  
World Wide ◽  
Ride Comfort ◽  
Vehicle Control ◽  
Vehicle Speed ◽  
Loss Of Control ◽  
Vehicle Model ◽  
Gradient Based ◽  
Profile Optimization ◽  
Set Up

Speed bumps are the most commonly used measure to control speeding in urban areas world wide. Specifications on profiles and dimensions are largely based on road tests. Studies into speed bumps, directed at evaluating their effectiveness in reducing accidents and their environmental impact, have brought some negative aspects concerning speed bumps to light. These aspects include incidents of spinal and neck injury or loss of control while speeding over speed bumps. Observations have also shown that speeding over certain speed bumps often result in an improvement in ride comfort, thus negating the effectiveness of speed bumps as a measure to control speeding. This paper addresses these aspects by considering the optimization of a speed bump’s profile. The profile is optimized by means of a validated non-linear four degree of freedom vehicle model, as well as the gradient based LFOPC optimization algorithm. The optimized profile allows for increased ride comfort at speeds at and below the designed speed. The ride comfort decreases with an increase in vehicle speed while the vehicle response remains within boundaries set up to reduce the possibility of injury or loss of vehicle control.

ENSURING THE PEDESTRIAN’S SAFETY DESIGN OF URBAN STREET CROSSWALKS

2019 ◽  
pp. 103-110
Author(s):  
Dmitriy Nemchinov
Keyword(s):  
Traffic Flow ◽  
Minimum Distance ◽  
Travel Speed ◽  
Vehicle Speed ◽  
Urban Street ◽  
Safety Design ◽  
Positive Practices ◽  
Time Required ◽  
Pedestrian Crossing ◽  
The City

The article presents an analysis of positive practices for ensuring the safety of pedestrians at the inter-section of the city streets carriageway, as well as a description of some innovations of regulatory and tech-nical documents, including an increased number of cases when a safety island can be arranged at a pedestri-an crossing. requirements for providing visibility at a pedestrian crossing to determine the minimum distance of visibility at a pedestrian crossing based on the time required pedestrians for crossing the roadway, recommended options for using ground unregulated pedestrian crossings on trapezoidal artificial irregularities according to GOST R 52605; traffic flow) and Z-shaped (also in the direction of the traffic flow), the requirements for the size of the securi-ty island have been established to allow put bicycle inside of safety island, a recommended set of measures to reduce the vehicle speed and describes the types of activities and describes a method of their application, describes methods zones device with reduced travel speed - residential and school zones, set requirements for turboroundabouts and methods of their design.

scholarly journals Smartphone monitoring of in-ambulance vibration and noise

2021 ◽  
pp. 095441192098599
Author(s):  
Tom Partridge ◽  
Lorelei Gherman ◽  
David Morris ◽  
Roger Light ◽  
Andrew Leslie ◽  
...  
Keyword(s):  
Transport Systems ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Noise Levels ◽  
The Road ◽  
Neonatal Transport ◽  
Mass Data ◽  
Transport Team ◽  
Vertical Accelerations ◽  
Noise Vibration

Transferring sick premature infants between hospitals increases the risk of severe brain injury, potentially linked to the excessive exposure to noise, vibration and driving-related accelerations. One method of reducing these levels may be to travel along smoother and quieter roads at an optimal speed, however this requires mass data on the effect of roads on the environment within ambulances. An app for the Android operating system has been developed for the purpose of recording vibration, noise levels, location and speed data during ambulance journeys. Smartphone accelerometers were calibrated using sinusoidal excitation and the microphones using calibrated pink noise. Four smartphones were provided to the local neonatal transport team and mounted on their neonatal transport systems to collect data. Repeatability of app recordings was assessed by comparing 37 journeys, made during the study period, along an 8.5 km single carriageway. The smartphones were found to have an accelerometer accurate to 5% up to 55 Hz and microphone accurate to 0.8 dB up to 80 dB. Use of the app was readily adopted by the neonatal transport team, recording more than 97,000 km of journeys in 1 year. To enable comparison between journeys, the 8.5 km route was split into 10 m segments. Interquartile ranges for vehicle speed, vertical acceleration and maximum noise level were consistent across all segments (within 0.99 m . s−1, 0.13 m · s−2 and 1.4 dB, respectively). Vertical accelerations registered were representative of the road surface. Noise levels correlated with vehicle speed. Android smartphones are a viable method of accurate mass data collection for this application. We now propose to utilise this approach to reduce potential harmful exposure, from vibration and noise, by routing ambulances along the most comfortable roads.

scholarly journals Research on Model Predictive Control for Automobile Active Tilt Based on Active Suspension

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 671
Author(s):  
Jialing Yao ◽  
Meng Wang ◽  
Zhihong Li ◽  
Yunyi Jia
Keyword(s):  
Load Transfer ◽  
Ride Comfort ◽  
Active Suspension ◽  
Path Tracking ◽  
Roll Angle ◽  
Lateral Acceleration ◽  
Vehicle Speed ◽  
Model Predictive Controller ◽  
Advantages And Disadvantages ◽  
Predictive Controller

To improve the handling stability of automobiles and reduce the odds of rollover, active or semi-active suspension systems are usually used to control the roll of a vehicle. However, these kinds of control systems often take a zero-roll-angle as the control target and have a limited effect on improving the performance of the vehicle when turning. Tilt control, which actively controls the vehicle to tilt inward during a curve, greatly benefits the comprehensive performance of a vehicle when it is cornering. After analyzing the advantages and disadvantages of the tilt control strategies for narrow commuter vehicles by combining the structure and dynamic characteristics of automobiles, a direct tilt control (DTC) strategy was determined to be more suitable for automobiles. A model predictive controller for the DTC strategy was designed based on an active suspension. This allowed the reverse tilt to cause the moment generated by gravity to offset that generated by the centrifugal force, thereby significantly improving the handling stability, ride comfort, vehicle speed, and rollover prevention. The model predictive controller simultaneously tracked the desired tilt angle and yaw rate, achieving path tracking while improving the anti-rollover capability of the vehicle. Simulations of step-steering input and double-lane change maneuvers were performed. The results showed that, compared with traditional zero-roll-angle control, the proposed tilt control greatly reduced the occupant’s perceived lateral acceleration and the lateral load transfer ratio when the vehicle turned and exhibited a good path-tracking performance.

Effect of unsupported sleepers on dynamic behavior of running vehicles and ride comfort index

2021 ◽  
pp. 095440622198937
Author(s):  
Mojtaba Azizi ◽  
Majid Shahravi ◽  
Jabbar-Ali Zakeri
Keyword(s):  
Numerical Model ◽  
Dynamic Behavior ◽  
Multibody Dynamics ◽  
Field Test ◽  
Ride Comfort ◽  
Vehicle Speed ◽  
Comfort Index ◽  
Railway Industry ◽  
Flexible Track ◽  
Train Speed

Nowadays, with various advancements in the railway industry and increasing speed of trains, the design of railway tracks and vehicles has become vitally important. One of the frequent problems of ballasted tracks is the existence of unsupported sleepers. This phenomenon occurs due to the lack of ballast underneath the sleepers. Here, a model is presented, in which a flexible track model in a multibody dynamics program is developed, in order to study the dynamic behavior of a vehicle. By utilizing the model, it is feasible to simulate unsupported sleepers on the flexible track including rail, sleeper, and ballast components. In order to verify the results of numerical model, a field test is performed. Findings indicate that, in the case of a single unsupported sleeper through the track, the ride comfort index increased by 100% after increasing the train speed from 30 to 110 km/h. Moreover, when it is needed to have ride comfort index improvement over the uncomfortable level, the vehicle speed should be less than 70 km/h and 50 km/h for tracks with one unsupported sleeper and two unsupported sleepers, respectively.

A Methodology for the Test Design and Evaluation of Human Whole-Body Vibration in Ground Vehicle Systems

1989 ◽  
Vol 33 (18) ◽  
pp. 1192-1196
Author(s):  
Ellen C. Haas
Keyword(s):  
Whole Body Vibration ◽  
International Standards ◽  
Whole Body ◽  
Test Design ◽  
Exposure Limits ◽  
Ground Vehicle ◽  
Body Vibration ◽  
Exposure Limit ◽  
Vehicle Systems ◽  
Iso 2631

To date, testing and evaluation of whole-body vibration in ground vehicle systems have not always fully utilized appropriate experimental design methodology, applicable statistical tests, or relevant criteria. A test design and evaluation methodology was developed to eliminate these oversights. This methodology uses inferential statistics, questionnaires, and a comparison of vibration data with representative mission scenarios. The methodology was employed in the evaluation of two alternative tracked ground vehicle designs. The independent variables were track type, terrain, vehicle speed, and crew position. The dependent variables were International Standards Organization (ISO) 2631 whole-body vibration exposure limit times at the lateral, transverse, and vertical axes. Two different multivariate analyses of variance (MANOVAs) performed on the exposure limit data indicated that all main effects, as well as several interactions, were significant (p < .01). A comparison of exposure limits to a representative mission scenario indicated that both track types would exceed ISO 2631 exposure, comfort, and fatigue limits during expected travel over cross-country terrain. Crew questionnaires also indicated crew discomfort when exposed to this type of terrain. The experiment demonstrated that the procedure was useful in helping to determine the extent that vehicle vibration permits the performance of the vehicle mission, within limits dictated by safety, efficiency, and comfort.

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