This paper attempts to measure the vehicle speed characteristics at few predetermined points along four residential roads. The selection of points to measure vehicle speed is to understand the ...changes in vehicle speed as the vehicles approach at and near the road humps. This study also considers the perceptions of the residents on the effects of road humps in reducing vehicle speed. The results show that the vehicle speeds at point immediately preceding and at the road hump decrease significantly but the vehicle speed increases at points immediately after the road humps. The relationship between the residential areas and the perceptions of the residents on both daytime and nighttime vehicle speed was found to be statistically significant. The perceptions of the residents on whether road humps can reduce vehicle speed were also found to be statistically significant when related with the residential areas.
This book focuses on aspects related to new perspectives and challenges in traffic and transportation engineering supporting energy saving in smart cities. Transportation, like other spheres of human ...activity, is constantly changing due to economic development. People are constantly improving the ways of moving using various energy sources, expanding infrastructures, and adapting cities to increasing traffic volumes. Many of the contents presented in this book are characterized by a multidisciplinary approach to a global problem. Topics of interest include, but are not limited to, the following: road traffic measurements; data analysis; road traffic (micro-, meso-, macro-) modeling; simulation models; road and intersection capacity; optimization, route choice; human factor in road traffic and transportation engineering; road safety; pedestrian and bicycle traffic and infrastructure; public transportation solutions; parking issues; contemporary problems of road traffic engineering and sustainable transportation; intelligent transportation systems (ITS); traffic control and management; smart grid services; electric mobility; environmental impacts of transportation systems; life cycle analysis (LCA) of alternative energy vectors for road vehicles; transportation systems and process modeling; sustainable transportation development; life cycle impact; fuel consumption; and emissions.
The increasing use of road vehicles has caused a number of transport and environmental issues throughout the world. To cope with them, traffic calming schemes are being increasingly implemented in ...built-up areas. An example of such schemes are Tempo-30 zones. The traffic calming measures applied as part of this scheme must be carefully planned in terms of location and design details in order to obtain the desired reduction in speed, traffic volume and exhaust emissions and, last but foremost, to increase the safety and facilitate the movement of vulnerable road users. The coexistence and combined effect of these measures and their design details must also be taken into account. The purpose of this study was to investigate whether the applied traffic calming measures had a considerable bearing on the reduction in speed to the desired level, as assumed in the traffic calming plan. Three street sections starting and ending with different intersection types were chosen to examine the synergy of the applied traffic calming measures. The numbers and speeds of vehicles were measured in three day-long continuous surveys. As it was expected, the amount of speed reduction depended on the hourly traffic volume on a one-way street and various other traffic engineering aspects. The obtained results may be used to modify the existing speed profile models and can guide traffic engineers in choosing the most effective traffic calming measures.
Road humps are designed to control the speed of vehicles through the discomfort that drivers experience when crossing over them. Although the use of various types of road humps in low-speed ...environments is common, its effectiveness has yet to be seen. This paper evaluated the effectiveness of different types of road humps in reducing the speed of vehicles at a university campus. Field observations were carried out to determine geometric designs of five round-top and five flat-top road humps. All recorded design characteristics of road humps were compared with the standard specifications by various authorities. Only road humps that met any one or more of the standard specifications were considered for speed data collection. Speed data were observed at two selected points during off-peak weekdays and in daylight conditions. A comparison of the observed design characteristics of the road humps with the standard specifications by the authorities showed that most of the humps did not meet any design standard except one round-top road hump and two flat-top road humps. However, only one round-top and one flat-top road humps were considered for further analysis. The average speed of vehicles approaching the road humps was found to be higher than the average speed observed on road humps, with a reduction of 46% and 52% for round-top and flat-top road humps, respectively. The results of statistical analysis also showed that both types of road humps were effective in reducing the speed of vehicles. Thus, it can be concluded that road humps, irrespective of their type, have an impact on vehicle speed.
Slow Streets promote walkability and provide safe spaces for active travel and recreation by minimizing vehicle traffic on roads. Their effectiveness was tested when the City of Tucson implemented ...Slow Streets by temporarily closing certain neighbourhood streets to all but local traffic, giving people more space to safely walk, run, and bicycle. Using a quasi-experimental research design, it was possible to measure differences in walking and bicycling between Slow Streets and control streets. Results show Slow Streets are effective in increasing the number of people walking and bicycling on neighbourhood streets, especially while the temporary traffic barriers were in place.
Traffic-calming measures (TCMs) are non-invasive devices designed to improve road mobility and urban areas on a human scale. Despite their potential, they have been in use for a long time and now ...have to deal with the latest technological innovations in the automotive field, such as cooperative driving technologies (CDTs), to improve energy efficiency in cities. The goal of this study is to explore the safety and operational performances of TCMs featuring CDTs in urban areas. An urban-scale road network close to a seaside area in the City of Mazara del Vallo, Italy, was properly redesigned and simulated in AIMSUN to assess several design solutions, where connected and automated vehicles (CAVs) have been employed as a more energy-efficient public transportation system. Preliminarily, the fine-tuning process of model parameters included CAVs and human-operated vehicles (HOVs) flowing through the network up to saturation conditions. The safety of the planned solutions was tested by using surrogate measures. The micro-simulation approach allowed us to know in advance and compare the operational and safety performances of environmentally friendly solutions involving TCMs and CDTs. These results can also support urban road decision makers in pivoting urban-traffic-calming-based design solutions featuring cooperative driving technologies toward energy efficiency transitions for smart cities.
•Vehicle speed was reduced within ±30 m from a speed hump location.•Fewer pedestrian crashes occurred near speed humps.•Crashes near speed humps involving pedestrians had lower severity of the ...injury.•The effects of speed humps were more pronounced in major roads.
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.
In Spain, on November 2020, a new law imposed that the generic speed limit on single carriageway two-lane roads is reduced from 50 km/h to 30 km/h.
The changes in the general rules of traffic, ...proposed by the Spanish government, are a sample of the evolution, in the use of the shared space of the streets, and at the same time shows its sensitivity towards road safety. Traditionally, the objective of the regulation was to attend to the growing increase in the use of motor vehicles (mainly cars), and for this reason, it was the protagonist in most of the articles of the General Traffic Regulations. Today, in many cities, the car is no longer the protagonist and shares the space on the streets, not only with other motor vehicles as buses or motorcycles, but also with pedestrians, bicycles, electric pedal-assisted cycles (EPAC), personal mobility vehicle (PMV), …
Pedestrian mobility is becoming more and more important every day but the number of pedestrians that died inside Spanish urban areas in road accidents is almost 50% of total urban areas road fatalities. In this sense, the mobility and road safety policies developed by local administrations have to focus on the objective of the reduction of accidents and their severity involving pedestrians and other vulnerable users in urban areas.
This article collects studies and experiences in other countries that show the effects of reducing the speed of motor vehicles in urban areas in order to reduce accidents and/or their severity if they occur. It also analyzes other options that reinforce this measure and that could help reduce this problem.
A usual traffic calming measure (TCM) to reduce vehicle speed in urban areas is the traffic lights that turn red when a vehicle exceeds the speed limit. These traffic lights can detect if an ...approaching vehicle exceeds the speed limit and, if so, stop it by means of a red light. It is generally employed in interurban roads rather than in big cities, where the presence of traffic lights is common. In a rural road crossing a small village, they are deployed to reduce the risk of accidents to vulnerable road used when vehicles arriving at high speeds tend to conflict with pedestrians attempting to cross the road. The aim of this paper is to analyze the efficiency of this TCM, preceded by panels indicating the vehicles’ speed, by controlling the vehicles’ speed in the A-132 road that crosses through the village of Azazeta in the province of Álava/Araba (Spain). Different sequence of the TCMs can be found in each direction approaching the village; in A direction, warning traffic lights, the panel indicating the speed and the traffic light turning red; and in B direction, the panel, the warning traffic lights and the traffic lights turning red. However, similar results were obtained in both directions for average speeds and percentile 85 of the speed distribution at the traffic lights, and speed was reduced as motorists faced the TCMs. However, although average speed was below speed limit (50 km/h), the percentile 85 was over it, implying that more than 26% of drivers did not respect the red light. Moreover, after the traffic lights turning red, motorist speed up and higher values were measured at the midpoint of the urban segment, the place where pedestrians use to cross from one side of the village to the other one, although no pedestrian crosswalk is available.
•The study evaluated the design of an urban collector road before it was implemented.•The effect of speed management strategies has been tested using driving simulator.•The speed behaviour is ...considerably influenced by engineering treatments introduced.•The engineering treatments improved the ability to detect of a sudden event.•The results support the driving simulation method to evaluate road safety measures.
Urban collector roads are complex driving environments often encompassing both the mobility and the access road functions. In these conditions motorized traffic and vulnerable road users compete continually. Speed reduction measures may play a relevant role in these contexts, provided that such measures are also designed in compliance with the driver’s capabilities and expectations.
The paper describes a test procedure using driving simulation experiments, designed to evaluate the reconfiguration project of Via Pistoiese, an urban road collector located in Florence (Italy). The road improvement design consisted of several engineering treatments aimed to reduce and homogenize the driving speed, as well as to manage the co-existence of the different road users and mainly to protect pedestrians. The main focus of the research was to understand if the drivers’ behaviour was according to the design hypothesis before the safety treatments are implemented in the real world. Due to the multiple engineering treatments included in the reconfiguration project, the evaluation of the overall safety effectiveness of the project rather than the single treatment safety impact was the main concern of the research study. In addition, the study aimed to assess the usefulness of the considered testing method to understand how to integrate road design with drivers' performances, especially in heterogeneous traffic environments where drivers’ behaviour plays a decisive role in the success of the proposed design solutions.
Fifty-eight participants drove through two immersive virtual environments, reproducing the existing configuration and the project reconfiguration, while data relating to different driving aspects were collected.
Two analyses were performed. The first was focused on the analysis of the mean speed profiles and revealed that the considered engineering treatments are able to control the speeding behaviour without providing a too high discomfort to the drivers. The second analysis was finalized to evaluate the driver's behaviour approaching zebra crossing, evaluating the impact of countermeasures allowing the drivers to perceive in advance a critical situation (a pedestrian that suddenly crossed the street) and consequently to perform a smoother and safer manoeuvre.
The experiments confirmed the validity of the considered engineering treatments, allowing expecting the improvement of the traffic safety in via Pistoiese, and support the usefulness of virtual reality experimentations to predict of the safety effectiveness of design solutions, taking into account the drivers’ behaviour.
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