Speed Humps Research Articles

Simulation of L-4 lumbar spine model of motorist exposed to vibration from speed hump

BackgroundThe motorcycle is often used in recurring travel between locations, dense traffic, poor conditioned roads and thus the repetitive loading on the musculoskeletal system of the rider leads to risk factors associated with musculoskeletal disorders. This study was aimed to examine the biomechanical response of the L-4 lumbar spine while riding the motorcycle on the speed hump at 20 km/h. MethodsThree-dimensional (3D) model of the L-4 lumbar spine was reconstructed based on the CT scan data obtained from the subjects. Material properties of the L-4 lumbar spine were assumed to be isotropic and homogenous. Mesh convergence and sensitivity analyses were performed and validated before simulation. Static and dynamic analyses were accomplished using quasi-static and steady-state dynamic analyses. ResultsStatic analysis results show that the highest stress concentrations were found around the pedicle and spinal canal. It is an expected commonplace for injuries because of loading. The dynamic simulation results showed the major resonance of the L-4 lumbar spine model is about 8–40 Hz. The stress, displacement, velocity, and acceleration value declines beyond 40 Hz as the frequency increases. ConclusionsThe simulation specifies the symmetric and unsymmetrical distributions of vibration magnitude regions of the lumbar spine. This study provides the modelling of the lumbar spine (L-4) and validated the effect of overloading failure as well as identified the biomechanical behaviour.

Effects of speed humps on vehicle speed and pedestrian crashes in South Korea

Introduction: Speeding is a crucial risk factor for pedestrian safety because it shortens reaction time while increasing the impact force in collisions. Various types of traffic calming measures to prevent speeding have been devised. A speed hump—a raised bump installed in the pavement—has been widely used for this purpose. Method: To evaluate the effectiveness of speed humps, the speed profiles of vehicles passing speed humps were analyzed along with pedestrian crash records near speed humps. Results: The speed profiles showed that vehicles gradually diminished their speeds starting 30 m ahead of speed humps and, immediately after passing the humps, accelerated to regain their original speeds within a distance of 30 m. This speed reduction effect is substantial on both local and major roads: 18.4% and 24.0% reduction in speeds, respectively. The analysis of pedestrian crash records revealed that, inside the zones of speed reduction effect near speed humps (i.e., ±30 m from speed humps), fewer pedestrian crashes per roadway distance occurred and pedestrian injuries were less severe, compared with events outside the effect zones. This safety improvement was greater on major roads than local roads. Practical Applications: This work finds that the speed reductions that occurred near speed humps were gradual and influential ±30 m from their locations, suggesting that the hump installations should be close enough to the pedestrian crossings. It is noteworthy that, albeit that speed humps are more prevalent on local roads, the benefits of speed reduction effects from speed humps were more pronounced on major roads than on local roads. Therefore, speed humps on major roads can be considered a more effective measure for pedestrian safety.

Optimum design of speed hump based on empirical data

Traffic calming techniques are extensively used as safety tools to reduce the speed of motorised vehicles along any type of paved road. The objective of this study is to evaluate the efficacy of isolated speed humps on urban roads in India and to suggest an optimised geometry of speed humps for the desired level of speed reduction. For this, five different urban road sections were identified in Delhi and video graphic data were collected at each study section. The median speed of vehicles at each grid is estimated and speed profiles were developed for each category of vehicle approaching the speed hump. The speed behaviour of the vehicles approaching a circular or parabolic shape of isolated speed hump are examined and compared. This study developed speed profile models using regression techniques for an individual vehicle and also for the combined data. The observed speed of the vehicle was considered as a response variable and the physical properties of the speed humps were considered as explanatory variables. Further, the combined linear equation was considered for determining the optimum height and entry radius of the speed hump for the desired speed by using the simplex method.

A Series of Vertical Deflections, a Promising Traffic Calming Measure: Analysis and Recommendations for Spacing

Traffic calming measures (TCM) are placed in urban areas to improve road safety, and among them, vertical TCMs are widely employed. Many researches are focused on the influence of the geometry of each measure on speed reduction, but it is demonstrated that drivers forget its effect and speed up after it. Therefore, placing consecutive TCMs can help to maintain a safe area. However, scarce literature can be found about the adequate spacing between them. Hence, the aim of this paper is to analyze the adequate distance between TCMs. Various streets with variable distances and different vertical TCMs were evaluated in Poland and Spain, including raised crosswalks, raised intersections, speed humps and speed cushions. The intermediate point between two TCMs was selected as the place where the maximum speed is achieved. Results showed that there was a good correlation between the speeds at intermediate points and the distance between TCMs, with a determination coefficient around 0.80. For an 85th percentile of the speed under 50 km/h, a maximum distance of 200 m between TCMs is recommended, and for a value of 40 km/h, 75 m.

The Effect of Speed Humps on Highways Pavement Condition

Speed humps used as a tool of traffic calming technique that applied to force drivers to reduce their vehicle’ speeds at some locations. For developed countries, the implementations of speed humps are often used within residential areas as well as at locations of schools crossing. For developing countries (e.g. Iraq), speed humps are used even at urban and urban highways. This paper investigates the effect of applying such speed humps on pavement condition index (PCI). For the purpose of this study, ten urban and rural highway sites that paved by asphalt concrete have been selected from Al-Diwaniyah city, Iraq. Each site has been divided to sections before and after the humps. Each section has been surveyed to record the distress types used in calculations the values of PCI. It has been noticed that the rutting distress is the dominant type for sections just before the humps. The PCI values were significantly lower at sections near the humps compared with the faraway sections. In addition, the effect of speed humps on the PCI values can be neglected at urban highways where minimal trucks used these highways. The results of the paper suggested that an attention should be provided to identify reasonable warrants for installing of speed humps on flexible highway pavements.

The Effect of Speed Humps on Instantaneous Traffic Emissions

Bad air quality due to free pollutants such as particulate matter (PM), carbon dioxide (CO 2 ), nitrogen oxides (NO x ) and volatile organic components (VOC) increases the risk of long- term health diseases. The impact of traffic-calming measures on air quality has been studied using specialized equipment at control sites or mounted on cars to monitor pollutants levels. However, this approach suffers from a large number of variables on the experiments such as vehicles types, number of monitored vehicles, driver’s behavior, traffic density, time of the day, elapsed monitoring time, road conditions and weather. In this work, we use a cellular automata and an instantaneous traffic emissions model to capture the effect of speed humps on traffic flow and on the generation of CO 2 , NO x , VOC and PM pollutants. This approach allows us to study and characterize the effect of many speed humps on a single lane. We found that speed humps significantly promote the generation of pollutants when the number of vehicles on a lane is low. Our results may provide insight into urban planning strategies to reduce the generation of traffic emissions and lower the risk of long-term health diseases.

Optimal design of traffic calming devices using computer simulation

ABSTRACT Speed control humps and dips are the most effective and widely used devices, to control vehicle speeds in urban areas. Their geometry varies from type to type based on the criteria used. This study aims at developing new designs for speed hump and dip using commercially available simulation and optimization software. The numerical simulation for vehicle-hump dynamics was developed using ADAMS software and then is linked to MATLAB software to determine speed hump/dip optimum designs that provide discomfort feeling to the driver if vehicle speed exceeds the specified limit, and tolerable comfort if speed is less than or equal the specified limit. The acceptable range of vibrations and shocks exposure resulted from passing over the humps or dips are based on British BS6841:1987 and ISO2631-5:2004 standards. These standards address human health and comfort level in terms of the acceptable range of whole body vibration exposure. The study shows that, for speed limits lower than 10 km/h and higher than 45 km/h, the optimal humps are more efficient than dips. On the other hand, the study shows that for midrange speed limits between 10 and 45 km/h, the optimal dips were superior over optimal humps.

Geospatial Distribution of Pedestrian Injuries and Associated Factors in the Greater Kampala Metropolitan Area, Uganda

Background: Road traffic injuries (RTIs) are the leading cause of death among 15-29-year olds, of which 22% are pedestrians. In Uganda, pedestrians constitute 43% of RTIs. Over 52% of these injuries occur in Greater Kampala Metropolitan Area (GKMA). However, information on geospatial distribution of RTIs involving pedestrians and associated factors is scanty. We established the geospatial distribution of pedestrian injuries and associated factors in GKMA, Uganda. Methods: We conducted a mixed methods cross sectional study in three districts of GKMA. We used a structured questionnaire to interview 332 injured pedestrians at ten purposively selected health facilities from May to July 2017. We used a modified Australian Walkability Audit Tool to assess road characteristics and videography to capture road user behaviour at reported injury sites. Injury location (outcome) was categorized into three locations according to primary land use: residential areas, commercial/business areas and bar & entertainment areas. The injury hotspots were then mapped out using Quantum Geographic Information System (QGIS). Multinomial logistic regression was used to identify factors associated with injury location and adjusted prevalence ratios (APR) reported at 95% confidence interval. Results: Males represented 66.5% (221/332) of the sample. Pedestrian injuries were most prevalent among 15-29-year olds (45.5%, 151/332). Most (47.2%, 157/332) injuries occurred in commercial and business areas. Namasuba-Zana (13%, 43/332) followed by Nakawa-Kireka on Jinja road (9.7%, 32/332) had the highest number of injuries. Presence of speed humps was protective (APR=0.13, 95%CI 0.01-0.93). However, zebra crossings (APR=6.41, 95% CI: 1.14-36.08) and clear traffic (APR=6.39, 95%CI: 2.75-14.82) were associated with high prevalence of pedestrian injuries. Conclusion: Presence of speed humps was safer for pedestrians but zebra crossings and clear traffic had more than 6-fold risk for injuries. Findings suggest that constructing speed humps on the roads in busy areas and sensitizing motorists to respect zebra crossings could reduce pedestrian injuries.

Critical Analysis of Speed Hump and Speed Bump and Geometric Design of Curved Speed Hump

The motive of this study is to critically analyze speed humps and bumps on various accounts such as travel time delays, mileage reductions, exhaust emissions and propose a new traffic calming device, which can retain the positive impacts of speed humps and also reduce the disadvantages associated with them. The new traffic calming device, Curved Speed Hump (CSH), consists of a main speed hump which is a raised and curved area placed along a lane and a complementary speed hump, adjacent to it. Drivers can choose to adopt a curved path, thus moderating speeds and avoiding disadvantages of speed humps. The primary objective of CSH is to moderate the speed, rather than locally reduce it, using both horizontal and vertical deflection concepts. Various geometric parameters are discussed and their theoretical limits are proposed.

Analysis of Speed Profiles at Speed Hump under Various Dimensions & Simulating their LOS Using VISSIM

Speed is an important parameter in transportation to attain the design principles. But a fast-moving vehicle can be a forbidding to other road users particularly in heterogeneous traffic. However, at some of the location’s speeds are controlled by different traffic calming devices to ensure safety. One of the most adopted traffic calming devices in India is speed hump. In this context an attempt is made to study various aspects related to speed hump in Indian context. The present study was done in two phases. The first phase of the study aims to focus on performance of speed hump of different dimensions for different vehicles and establishes a statistical relation between the dimensions of speed hump and vehicular speed using multilinear regression analysis. Calibrated results had shown that there is more than 70% of variation in speed reduction due to change in hump geometry. This study also describes practical geometric design guidelines of speed hump for the use of practicing road engineers. The second phase of the study aims to estimate the performance of vehicles at speed hump by evaluating the delays and level of service of the selected study areas in presence of humps and in absence of humps using micro simulation software VISSIM. Results had shown that due to more number of speed humps Level of Service (LOS) is affected to large extent. These results can be used as a tool for designing hump geometry.

Speed humps and speed tables: Externalities on vehicle speed, pollutant emissions and fuel consumption

Abstract Speed hump/table are devices used on roadways with the objective of reducing vehicular speed. Nevertheless, the effects of said devices on traffic streams are not that clear. Therefore, through descriptive statistics and approximations of linear models, an analysis was carried out on a collector street, as a case of study, taking into consideration the shapes and spacing of bumps, and pollution and fuel consumption of vehicles. The results indicate that the shape and size of the speed control devices are the most important factors for efficiency in reducing maximum speed between devices, achieving a reduction of 50%–75% with speed humps, and a 10%–65% reduction of maximum speed in those which are trapezoidal shape (speed tables). The spacing between speed control devices does not significantly effect a vehicles speed upon passing over said devices, but it does have an impact on pollutant vehicle emissions and extra gasoline consumption. The estimated models to calculate the speed control device characteristics can help to determine which geometric shapes to use when deciding about type and placement of the device, depending on the requirements of a particular thoroughfare.

Examining the Speed Reduction Characteristics of Urban Residential Streets in the Upstream Side of Speed Humps

Examining the Speed Reduction Characteristics of Urban Residential Streets in the Upstream Side of Speed Humps

Simulating the Effect of Speed Humps on the U-Turn Traffic

Traffic simulation represents an effective tool for evaluating the suggested alternatives to enhance traffic conditions prior to their application in real sites. U-turn sections represent examples of the complicated sections that cannot be analyzed properly without applying microsimulation approach. Recently, in Iraq, speed humps were applied in prior to the merging locations and U-turn sections to enhance traffic safety. However, the characteristics of traffic at U-turn section with the presence of speed humps have got little attention in previous literatures. This paper uses VISSIM microsimulation model to emulate traffic movements at selected U-turn sites in the cases of with and without speed humps. Three median U-turn sites have been selected where two of these sites have speed humps prior to the turning locations. Real traffic data have been obtained from these sites using video recordings to estimate specific parameters. The developed simulation models were successfully calibrated and validated with the real data. The models have been used in testing different scenarios including the effect of having different locations/ types of speed humps and finding the capacity of U-turn sections. The results showed that closer the speeds hump to the turning location is lower the time spent for merging. The time spent values are increased with the increasing of traffic speeds at humps. Higher capacity value is obtained for the site with an auxiliary lane and speeds hump compared with the other sites.

Study of the stresses in the front suspension components of a car passing over speed breakers

To reduce the speed of vehicles before pedestrian crossings or as a warning for lowering the speed, vertical deflection devices or road profiles are placed transversely to the direction of travel. The type of profiles is different – speed bumps and humps with different height and length. Some of the profiles have the task of alerting the driver of changing conditions or potential danger - such are the rumble strips, while others aim to force the driving speed below 30 km/h. The amplitudes of the second profiles are considerably larger than those of the first and can cause significant stresses in the front suspension elements and its connections. The purpose of the study is to obtain information on the load on the front suspension components when passing over speed breakers.

An efficient urban localization method based on speed humps

Outdoor localization is of great importance for driving navigation, attracting many research efforts in past decades. Prevailing GPS achieves meter-level localization accuracy under general outdoor conditions. Yet, GPS service performs poorly in urban canyons where skyscrapers block GPS signals and drain mobile phone battery quickly within few hours. In this work, we exploit common city facilities, i.e., speed humps, as an indicator for vehicle location. The key insight is that when the vehicle passes through the speed bump, it experiences significant fluctuations, causing larger acceleration in the vertical direction. On this basis, we design a localization scheme that utilizes the accelerator equipped on modern smart phones to track sequence of speed bumps, which is further transferred into sequence of moving directions of the vehicle, and adopt effective road mapping technology to derive real-time location. As we have concerned, it is the first attempt to exploit the spatiotemporal characteristics generated by the speed humps to recover the trajectory of the travelling route and infer the current position. Experimental results in typical outdoor environment (campus) demonstrate a comparable performance with GPS method, yet achieve lower energy consumption.

An approach for the determination of optimal speed hump/table profiles by field tests and simulation stage

The study presented here attempts to establish an approach for the selection of optimum speed hump/table profiles that were produced during simulation stage by taking into account different speed ranges. For this purpose, in-situ and simulation tests were carried out in which root-mean-square (rms) values were obtained. Field tests were performed on seven parabolic speed humps and one trapezoidal speed table within the boundary of Istanbul Technical University Ayazaga Campus Area. These tests were conducted twice with different loads. As in-situ tests focused on the measurement of the vertical acceleration when crossing the speed hump/table, rms values were recorded by means of an accelerometer, a data logger, a Testlab Network software and a computer. As for the numerical model in the simulation tests, a general purposed finite element simulation software Ls-dyna 3.1 version was used. Results from the field tests and the simulation were compared in order to calculate a correction factor for each vehicle speed range considered during the experiments. These correction factors have enabled the transfer of simulation results to real environment. Consequently, an approach has been established in terms of selecting the optimum speed hump/table profiles.

Influence of speed bumps on braking distance

This paper aims to dismiss the popular belief that speed bumps reduce the vehicle speeds or reduce the braking distance. In recent years, the implementation of speed bumps on public roads in Romania has increased. The correct understanding of the role of the speed bump has been misunderstood by the Romanian authorities who use them to slow down traffic on highly used roads. More advanced countries in the segment of traffic controlling and traffic safety have special rules for speed humps and speed bumps. This paper is concerned with the theoretical and experimental study of the performance of the vehicle in emergency braking when passing over such a speed bump. The theoretical study is done by using mathematic formulas and the experimental study is done by using a real car and testing it’s braking distance in normal weather on a dry road that has a speed bump implemented. The study shows the influence of the induced forces from the speed bump in the car dynamics, once because of the low adhesion surface of a worn out speed bump and secondly because of the changes in normal force on the wheel after passing over the hump, the influence of the suspension loading is also backed up by the Tr. Ori study.

Impact of Road Humps on the Pavement Surface Condition

In order to fight against over-speeding, the government and people in Egypt resorted to the installation of speed humps without adequate studies. On this basis, speed humps became widespread in most of the Egyptian roads in a semi-random way. It has been observed that the pavement condition of the roads has deteriorated in the vicinity of these humps. For impact assessment of speed humps on the pavement condition index (PCI), three roads link Kafr El-Sheikh city with three major towns in Kafr El-Sheikh governorate were selected to conduct PCI survey. The results indicated that the presence of speed humps contributes greatly to reduce the pavement condition index (PCI) values. It should be mentioned that the average reduction in PCI values ranged between 15% and 22% due to the presence of speed humps. Also, the most frequently observed distress on the pavement sections including humps considered for the selected roads was Raveling and Rutting. Accordingly, to avoid the pavement defects at the locations where the speed humps are installed, it is proposed to study the structural section of the road in the vicinity of the speed hump to resist the braking force and speed reduction effect.

A multinomial logit analysis of factors associated with severity of motorcycle crashes in Ghana

Objective: The objective of this study was to explore the factors affecting motorcycle crash severity in Ghana.Methods: A retrospective analysis of motorcycle crash data between 2011 and 2015 was conducted using a motorcycle crash data set extracted from the National Road Traffic Crash Database at the Building and Road Research Institute (BRRI) in Ghana. Injury severity was classified into 4 categories: Fatal, hospitalized, injured, and damage only. A multinomial logit modeling framework was used to identify the possible determinants of motorcycle crash severity.Results: During the study period, a total of 8,516 motorcycle crashes were recorded, of which 22.9% were classified as fatal, 42.1% were classified as hospitalized injuries, 29.4% were classified as slight injuries, and 5.6% were classified as damage-only crashes. The estimation results indicate that the following factors increase the probability of fatal injuries: At a junction; weekend; signage; poor road shoulder; village settlement; tarred and good road surface; and collision between motorcycle and heavy goods vehicle (HGV). Motorcycle crashes occurring during the daytime and on the weekend increases the probability of hospitalized injury. The results also suggest that motorcycle crashes occurring during the daytime, in curves or inclined portions of roads, or in unclear weather conditions decrease the probability of fatal injury.Conclusions: This study provides further empirical evidence to support motorcycle crash modeling research, which is lacking in developing countries. The ability to understand the various factors that influence motorcycle crash severity is a step forward in providing an appropriate basis upon which informed motorcycle crash policies can be developed. Particular attention should be given to the provision of road signage at junctions and speed humps and controlling traffic during the weekend. In addition, road maintenance should be carried out periodically to address motorcycle safety in Ghana.

Design, Fabrication and Analysis of Varying Loads on Speed Hump

Design, Fabrication and Analysis of Varying Loads on Speed Hump