Energy and Environmental Implications of Using Energy-Harvesting Speed Humps in Nablus City, Palestine

Over the last three decades, transportation has become one of the main energy-consuming sectors around the world and, as a result, large amounts of emissions are produced, contributing to global warming, climate change, and health problems. Therefore, huge investments and efforts have been made by governments and international institutions to find new renewable and clean sources of energy. As a contribution to these efforts, this study determined the practical energy and environmental implications of replacing conventional speed humps with energy-harvesting speed humps in Nablus city, Palestine. The study was implemented using an energy-harvesting speed hump (EHSH) system developed in the laboratories at An-Najah National University and based on comprehensive traffic volume counts at all speed humps’ locations. In addition, a traffic volume prediction model was developed in order to determine the implications over the next 10 years. As a result of the study, the expected annual amount of generated energy was determined. Moreover, the expected reduction in greenhouse gas (GHG) emissions and the reduction in the cost of roadway network lighting were determined based on the current and future traffic conditions.

Impact of vertical traffic calming devices on environmental noise

Increasing numbers of people living in urban areas are being exposed to harmful action of environmental noise, which severely affects their health and quality of life. The predominant source of environmental noise in such areas is road traffic, and a frequently used measure to curb down this noise involves reduction of driving speed. The influence of vertical traffic calming devices, normally used to improve traffic safety, on the degree of noise reduction, is analysed in this study. The analysis was carried out on seven urban two-lane two-way roads, on which various types of speed bumps and speed humps are installed.

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 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.