Traffic Calming Measures Research Articles

Speed management as a measure to improve road safety on Polish regional roads

The article presents the issue of the implementation of speed management measures on regional roads, whose character requires the use of different solutions than those on national roads. The authors briefly described speed management measures, the conditions for their implementation and their effectiveness with reference to environmental conditions and road safety. The further part of the paper presents selected results of the authors' research into the speed on various road segments equipped with different speed management measures. The estimations were made as to the impact of local speed limits and traffic calming measures on drivers' behaviour in free flow conditions. This research found that the introduction of the local speed limits cause reduction in average speed and 85th percentile speed up to 11.9 km/h (14.4%) and 16.3 km/h (16.8%) respectively. These values are averaged in the tested samples. Speed reduction depends strongly on the value of the limit and local circumstances. Despite speed reduction, the share of drivers who do not comply with speed limits was still high and ranged from 43% in the case of a 70 km/h limit, up to 89% for a 40 km/h limit. As far as comprehensive traffic calming measures are concerned, results show decrease in average speed and 85th percentile speed up to 18.1 km/h and 20.8 km/h respectively. For some road segments, however, the values of average speed and 85th percentile speed increased. It confirms that the effectiveness of speed management measures is strongly determined by local circumstances.

Comparison of discomfort caused by speed humps on bicyclists and riders of motorized two-wheelers

Speed humps have been used extensively across the world as effective traffic calming measures. Speed humps are typically used in areas where interactions between motorized and non-motorized users are expected, such as residential areas, urban areas, near school zones, and shopping areas. In these areas, various other users including pedestrians and bicyclists would be present. However, the impacts of speed humps on the non-motorized users have not been explored well so far. In this study, an attempt is made in this direction, focusing on discomfort of bicyclists while passing over speed humps. An experiment is conducted using nine volunteers who were asked to ride instrumented bicycles and motorized two-wheelers over speed humps of varying geometry at different speeds and report the level of discomfort they felt in Borg CR 10 scale. The vibration values were also recorded. When the responses of riders were considered, it was observed that for the same speed, the bicyclists experienced higher discomfort than that by riders of motorized two-wheelers while passing over the humps. For the same geometry, the critical speeds after which the riders feel discomfort are much lower (about 4km/h) for bicyclists than that of riders of a motorized two-wheeler.

Considering built environment and spatial correlation in modeling pedestrian injury severity

ABSTRACTObjective: This study looks at mitigating and aggravating factors that are associated with the injury severity of pedestrians when they have crashes with another road user and overcomes existing limitations in the literature by focusing attention on the built environment and considering spatial correlation across crashes.Method: Reports for 6,539 pedestrian crashes occurred in Denmark between 2006 and 2015 were merged with geographic information system resources containing detailed information about the built environment and exposure at the crash locations. A linearized spatial logit model estimated the probability of pedestrians sustaining a severe or fatal injury conditional on the occurrence of a crash with another road user.Results: This study confirms previous findings about older pedestrians and intoxicated pedestrians being the most vulnerable road users and crashes with heavy vehicles and in roads with higher speed limits being related to the most severe outcomes. This study provides novel perspectives by showing positive spatial correlations of crashes with the same severity outcomes and emphasizing the role of the built environment in the proximity of the crash.Conclusions: This study emphasizes the need for thinking about traffic calming measures, illumination solutions, road maintenance programs, and speed limit reductions. Moreover, this study emphasizes the role of the built environment, because shopping areas, residential areas, and walking traffic density are positively related to a reduction in pedestrian injury severity. Often, these areas have in common a larger pedestrian mass that is more likely to make other road users more aware and attentive, whereas the same does not seem to apply to areas with lower pedestrian density.

Repurposing the paving: The case of surplus residential parking in Davis, CA

The city of Davis, CA, has a rich history of high bicycling levels, and the city has ambitious transportation policies and goals. However, both the city of Davis and transportation scholars have overlooked the potential opportunities a surplus of on-street residential parking provides to cities. The existing literature on the influence of parking policy and provision has focused primarily on commercial districts and on large metropolises, neglecting parking in more purely residential areas. In this descriptive case study, we systematically observed the number of cars on a transect of residential streets in the early morning and late evening on weekdays to conservatively estimate the average peak parking demand by residents as a percentage of available parking spaces. On average, only 2 in 7 available parking spaces were occupied during peak hours. We note that the over-provision of on-street parking in residential neighborhoods could be a nexus for the city to achieve its sustainable transportation policy goals while addressing its fiscal and housing supply challenges. We discuss possible design solutions, including providing ecosystem services, implementing traffic calming measures, and creating accessory dwelling units.

Traffic Calming Measures: An Evaluation of the Effect on Driving Speed

Road accidents are one of the leading causes of death in the world, particularly among young people. Excessive speed is one of the main risk factors in road traffic safety, increasing accident probability and affecting accident severity. Experimental research of the traffic calming measures allocation effect on the driving speed is presented in this paper. The research has been carried out on two aspects. The first one with respect to the mean speed and the second one regarding instantaneous speed. However, the paper is not only restricted by the above research. Standardized survey interview and questioning, a survey of public opinion, was carried out to find out the road users’ opinions about the need for traffic calming measures and speed control measures. Finally, the authors presented their insights and recommendations for the installation of speed humps and gateways and their optimum spacing.

Traffic Calming and Neighborhood Livability: Evidence from Housing Prices in Portland

This paper examines the impact of traffic calming on the livability of urban residential streets. Using geo-referenced data on the installation of 1,187 calming devices in Portland, Oregon, I test whether the interventions locally affect housing prices during succeeding years. I provide reduced-form evidence that city dwellers pay significant premiums to limit their exposure to motor vehicles, but obtain mixed results regarding the overall price impacts of calming devices. My estimates suggest that only the most effective traffic calming measures have a detectable impact on housing prices. The implied traffic flow elasticity is -0.07: projects decreasing traffic by 16% raise home values on treated streets by 1%.

Unified methodology for estimating efficiency of traffic calming measures – example of Estonia

Traffic calming is an integral part of contemporary traffic planning and traffic management being used for fulfilling different tasks such as reducing vehicle speed and traffic volume, and in final terms reducing number of accidents. Traffic calming measures are notstandardized internationally and have significant differences in geometric shape and layout in different countries, as well as in Estonia. At the same time impacts of different calming measures are unstudied well, and often the surveys are incomparable to each other. There are also no certain recommendation which measures should be implemented under different conditions. One of the reasons for that is lack of tested methodology for estimating the effectiveness of calming measures. This paper describes research that aimed at developing such a methodology and conducting a pilot study to test it. Effectiveness of traffic calming measures is estimated from the perspectives of vehicle speed and public acceptance. The new methodology assumes conducting an experiment. It allows comparing efficiency of two or more measures of the same type. The pilot study was conducted in Tallinn with a sample of 30 drivers. Results of this study proved that the new methodology is suitable for estimating effectiveness of traffic calming measures.

Crash analysis at intersections in the CBD: A survival analysis model

Enhancing the safety level of urban roads especially in CBDs is paramount. Due to a large number of intersections in what is usually a grid road system in the CBDs, we investigate crashes occurring in and around an intersection. The question of interest in this study is: does the nature of crashes at intersections differ from those of the roads at midblock? Stated more precisely, considering the intersection as a reference point, does the distance to the reference point (i.e. midblock locations on the roads) correlate with different types of crashes compared to that of the intersection? A right answer can lead traffic engineers and safety auditors to propose different safety measures at intersections and the midblock locations. As a pilot study, we collected the last 9years crash data of the CBD of Melbourne, Australia. For the first time, we employ Survival Analysis models -including Exponential, Weibull, and Log-logistic- to investigate a space-dependent phenomenon (i.e. accidents at proximity to the intersection). Of the outcome, highlights are: (i) police presence at busy intersections during busy night outs and weekends highly improves the pedestrian safety (ii) raised crossings at midblock locations lower likelihood of crashes of pedestrians as well as cars, (iii) lighting conditions at intersections must be watched and kept at a high level. (iv) Severity, likelihood, and location have no known association with the level of congestion. In other words, safety is first, always and everywhere. The results can be of interest to traffic authorities and policy makers in reinforcing traffic calming measures in the cities. The codes developed in this study are made available to the research community to be used in further studies.

Association between intersection characteristics and perceived crash risk among school-aged children

This research examined how environmental attributes near intersections influence the perceived crash risk among school-aged children, which provides information on the potential risks of pedestrian crashes that can guide the development of proactive countermeasures. In a sample of 799 children aged 10–12 years old in Korea, the environmental attributes of intersections perceived as having a high risk of producing crashes near elementary schools were investigated using standard negative binomial and zero-inflated negative binomial models.The results showed that a higher number of student crossings, a wider road width, the presence of crosswalks, student-friendly facilities at the intersection, and four-way intersections were significant and positively associated with perceived crash risk among school-aged children. The findings related to building characteristics indicated that a higher number of entrances at an intersection increased the perceived crash risk while higher visibility at the intersection reduced the perception of risk. Associations with traffic-calming measures were weak,suggesting that the measures used in the study areas were not effective in reducing the perceived crash risk. The results of a police-reported crash model showed that school-aged children have a relatively accurate perception of crash risk and that the perceived crash risk of school-aged children may provide valuable information on the intersection characteristics in need of attention near school sites.

A THEORETICAL OVERVIEW OF ROAD HUMP EFFECTS ON TRAFFIC SPEED IN RESIDENTIAL ENVIRONMENTS

This paper is part of an ongoing study to analyse the effectiveness of road humps as a traffic calming measure in improving the residential living environment. A review was conducted on various literatures concerning the effects of road humps on vehicle speeds, particularly in residential areas. The major findings from the literatures are that the vehicles’ operating speeds are affected by the hump design and spacing in between humps. An incorrect hump profile will also potentially result in passenger discomfort and vehicle damage. Public perceptions also agreed that road humps are effective in reducing vehicle speeds. More studies should link field study results with residents’ perceptions particularly in Malaysia, while considering the effect of road geometrics and other devices possibly impacting vehicle speeds along selected roads. Further research also needs to be done to test the effectiveness of current schemes in Malaysian residential areas, as many are on an ad-hoc basis.

A THEORETICAL OVERVIEW OF ROAD HUMP EFFECTS ON TRAFFIC SPEED IN RESIDENTIAL ENVIRONMENTS

This paper is part of an ongoing study to analyse the effectiveness of road humps as a traffic calming measure in improving the residential living environment. A review was conducted on various literatures concerning the effects of road humps on vehicle speeds, particularly in residential areas. The major findings from the literatures are that the vehicles’ operating speeds are affected by the hump design and spacing in between humps. An incorrect hump profile will also potentially result in passenger discomfort and vehicle damage. Public perceptions also agreed that road humps are effective in reducing vehicle speeds. More studies should link field study results with residents’ perceptions particularly in Malaysia, while considering the effect of road geometrics and other devices possibly impacting vehicle speeds along selected roads. Further research also needs to be done to test the effectiveness of current schemes in Malaysian residential areas, as many are on an ad-hoc basis.

Impact of speed humps of bicyclists

Speed hump is one of the most popular and economical traffic calming measures used globally. It induces shocks and vibrations in the vehicles passing over it. Hump aims to force the driver to reduce the vehicle speed to an optimum speed at which the discomfort is minimum. Extensive studies have been conducted to understand the vibration effect. In developing countries such as India, a large percentage of population uses bicycle or other non-motorized vehicles routinely. This study aims to understand the effects speed humps on bicycle riders. Variables such as geometry of the hump, speed of the vehicle, and riding posture of the driver are considered to understand the discomfort levels in detail. A set of volunteers in bicycles were asked to go over speed humps of different geometry at varying speeds and report the level of discomfort they felt. The vibrations were recorded by accelerometers installed on the handle bar, seat, and neck of the rider for measuring vibrations. These readings from accelerometers were converted to vibration dose values for evaluation. The same procedure was carried out for motorized two-wheeler riders also. The result shows that the bike riders experience the same level of discomfort as that of riders of motorized two-wheelers at a much low speeds. This study shows that unless proper considerations for bicycle riders are made, speed humps which is the most popular speed calming device used across the world could harm the bicyclists, which in turn could negatively impact the bicycling level of the region.

Development and application of traffic accident density estimation models using kernel density estimation

Traffic accident frequency has been decreasing in Japan in recent years. Nevertheless, many accidents still occur on residential roads. Area-wide traffic calming measures including Zone 30, which discourages traffic by setting a speed limit of 30 km/h in residential areas, have been implemented. However, no objective implementation method has been established. Development of a model for traffic accident density estimation explained by GIS data can enable the determination of dangerous areas objectively and easily, indicating where area-wide traffic calming can be implemented preferentially. This study examined the relations between traffic accidents and city characteristics, such as population, road factors, and spatial factors. A model was developed to estimate traffic accident density. Kernel density estimation (KDE) techniques were used to assess the relations efficiently. Besides, 16 models were developed by combining accident locations, accident types, and data types. By using them, the applicability of traffic accident density estimation models was examined. Results obtained using Spearman rank correlation show high coefficients between the predicted number and the actual number. The model can indicate the relative accident risk in cities. Results of this study can be used for objective determination of areas where area-wide traffic calming can be implemented preferentially, even if sufficient traffic accident data are not available.

EVALUATING THE APPLICATION OF DIVERGING DIAMOND INTERCHANGE IN ATHENS, ALABAMA

A diverging diamond interchange (DDI), a freeway and arterial interchange design, uses crossovers at the ramp intersections to eliminate conflicts between arterial through traffic and the left turning traffic from both the arterial and the ramps. The conventional diamond interchange (CDI) compared with the DDI has similar on-ramps and off-ramps, but there is a change in the number of lanes on the arterial. A case study has been conducted for an interchange in Athens, Alabama. The existing interchange is a conventional diamond interchange which is compared with a DDI built at the same location by using Synchro/Simtraffic as a simulation tool. The analysis focused on determining level of service and vehicle delay for the two interchange types. In this project effort was made to know if a DDI is the right solution for all interchange locations through the examination of a single location and adjustments to traffic volumes under numerous combination of turning movement scenarios where variation of capacity and the influence of proximity of adjacent intersections were also included. Finally, it was concluded that DDI cannot be an appropriate measure to improve the current CDI network for the study area since only 4 special cases it performs better than CDI. And DDI cannot be the effective traffic calming measure if it is associated with upstream or downstream intersections.

DEVELOPMENT OF A FUZZY EXPERT SYSTEM TO PRIORITIZE TRAFFIC CALMING PROJECTS

Nowadays, due to the constraints of budget and time, the prioritization of traffic calming projects before installation of traffic calming measures is vital for transportation engineers and urban planners. The purpose of this study is to develop an expert system for prioritizing streets that are affected by problems associated with traffic safety using Fuzzy Logic. Expert systems have been used widely and globally for facilitating decision-making processes in various fields of engineering. Due to the uncertainty and vagueness in traffic and transportation related problems, the use of fuzzy logic in the inference engines and decision-making processes of expert systems, is effective. In the proposed expert system, effective parameters in prioritizing traffic calming projects in residential streets including traffic volume, residential density, differential speed and number of accidents are investigated. The Fuzzy Logic toolbox, which is embedded in MATLAB (R2010b), is employed to design and simulate this expert system on the basis of Fuzzy Logic. A specific GUI was developed for this purpose. By developing this system, engineers and decision-makers will be able to rank projects according to their importance. This expert system was tested through prioritizing a number of residential streets in the city of Tehran. The output of the tests showed that the proposed system is helpful in prioritizing different traffic calming projects. Finally, the evaluation of the system was conducted. According to the assessment, most evaluators acknowledged the efficiency and effectiveness of the system.

Traffic Calming Measures and their Effect on the Variation of Speed

In recent years the number of deaths and serious injuries is decreasing in Spain, but, although the reduction outside the cities has been very strong, inside the urban areas, it has been smaller. This is especially hard if you look at the most vulnerable road users such as pedestrians and cyclists. In many accidents the speed factor appears closely linked not only to the number, but also to the severity of the accidents suffered inside the urban areas. Therefore, a reduction in the speed would improve the road safety.There are different measures known as “traffic calming measures” whose objectives are to reduce both the number and severity of accidents that occur on urban areas, by reducing the traffic flow through the streets, as well as the speed of the vehicles. However, the efficiency in speed reduction of each measure is not entirely known. That's the reason why they are implanted, in many cases, with no technical basis.The aim of this article is to show the effectiveness in reducing speed of some of the traffic calming measures. To this effect, field measurements were done on street sections with different types of traffic calming measures, in different places of a city of Burgos, in the north of Spain. These measurements were compared with other ones sited on other streets sections of similar characteristics but without traffic calming measures.Finally the conclusions are shown and some recommendations for improving their effectiveness are given.

Bicycle Education for Children: Evaluation of a Program in Montreal, Quebec, Canada

The promotion of bicycle use by school-aged children is one way to encourage more active lifestyles. The purpose of this study was to evaluate an on- and off-bicycle education program for school-aged children in Montreal, Quebec, Canada, to understand how education influences the cycling behavior and attitudes of children and parents. Qualitative measures and descriptive statistics were used to analyze pre- and postprogram survey results from children who participated in the program and their parents. Results showed that children’s knowledge of bicycle safety increased and that participants made significant improvements in their knowledge of bicycle-specific street signs (before = 83%, after = 92%) and hand signals (before = 68%, after = 96%). Children also became more confident. Before the program, 75% of participants stated that to ride a bicycle was not difficult for them. After the program, this percentage increased to 92%. The parents of the participants also reported improvements in their children’s cycling abilities, and 55% stated that they would allow their children to participate in an organized cycle-to-school program. In addition, half of the parents included in the postprogram survey stated that their behavior, attitudes, or both, toward cycling had become more positive as a result of their child’s involvement in the bicycle education program. To encourage cycling in any region, bicycle educators and advocacy groups can develop school-based bicycle education programs as well as cycle-to-school programs. City planners should consider implementation of policies that encourage the development of bicycle infrastructure and traffic calming measures, especially near schools, to encourage parents to allow their children to bicycle to school.

Getting an Insight into the Effects of Traffic Calming Measures on Road Safety

The objective of this paper is to assess the significance of urban traffic calming and to get an insight into the safety impacts of local and area-wide traffic calming interventions enabling a better understanding and therefore ‘better-informed’ decisions on different schemes. Safety effects of traffic calming initiatives have been analysed on a city-level for larger Hungarian cities and an in-depth research has also been carried out for a more detailed case from the capital of Hungary. Results show that traffic calming initiatives have a very significant role in enhancing road safety of urban areas. Meanwhile the case study of Budapest explains observed effects in detail allowing for more accurate appraisal tools to be developed.

Impact Assessment of Speed Calming Measures on Road Safety

Traffic calming and speed reduction are one of the core factors that influences traffic accident rate and severity. In the last decades a lot of speed calming measures were implemented in the Lithuanian roads of national significance and city streets. As it was foreseen the result was very effective. The paper presents research methodology and analysis of results of vertical traffic calming measures (speed bumps, speed humps, raised crosswalks), safety islands and speed cameras influence to the road safety on Lithuanian roads.

Race to the top in traffic calming

AbstractWe study the competition of two suburbs facing transit traffic flows. The suburbs are substitutes for transit traffic. In the absence of toll measures, the symmetric Nash equilibrium with two local governments leads to a race to the top in traffic calming measures that increases the cost of travel. The Nash equilibrium is compared to two types of centralized decisions: the symmetric solution and the asymmetric solution. The asymmetric solution that concentrates all transit traffic in one suburb is better but can only be realized if the authority over the local roads is transferred to the central authority.