The aim of this paper is to shed light on the effect of Low Emission Zones (LEZs) on traffic. LEZs are areas in which access is restricted for the most polluting vehicles. They have been found to be ...effective in reducing pollution, while the expected effect on traffic is not clear. Using high-frequency granular data on traffic for the city of Madrid, I analyze whether LEZ schemes are effective in reducing flow and density within the area of implementation and whether they generate a displacement effect. Taking advantage of the exogeneity of the implementation timing, I develop a pre/post analysis based on time. Results suggest a reduction in traffic inside the restricted area and a displacement to all the other areas of the city. I find a switch to public transport for commutes directed towards the restricted area and rerouting of trips for destinations outside Madrid Central to be two of the possible mechanisms explaining these results. The reduction in traffic inside the restricted area gradually decreases over time and disappears after 7 months. This is consistent with the renewal of the vehicles’ fleet with unrestricted and cleaner vehicles generated by the policy.
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.
We characterized the air pollution exposure of cyclists in the city center of Curitiba (Brazil) and then systematically analyzed the influence of several traffic management strategies (bus lanes, ...bicycle lanes, traffic calming area, traffic lights, and cleaner vehicle technologies) on the exposure. We focused on concentrations of particulates monitored on-board bicycles: PM2.5, black carbon mass (BC) and particle number concentration (PNC), and also reported on total volatile organic compound concentrations (TVOC). Overall, mean (± standard deviation) exposure was moderate compared to other cities around the world (BC: 6.98 ± 11.53 μg m‐−3, PM2.5: 33.22 ± 25.64 μg m−3, PNC: 3.93 × 104 ± 4.17 × 104 cm−3, TVOC: 361 ± 99 ppb). Concentrations were higher in the morning rush hour than in the afternoon traffic peak, and exhibited a large spatial variability. Bus stops and signalized traffic intersections emerged as hotspots when compared to the rest of the journey, increasing all particulate concentrations. Lower exposure was found on streets with low traffic (particularly, small number of heavy-duty vehicles) and within shallow canyon structures. The impact of traffic calming areas on cyclists' exposure is still inconclusive and further experimental and modelling studies are needed. Simple emission calculations based on traffic activity and real-world emission factors suggested that replacing the diesel bus fleet with hybrid electric buses might largely decrease (64%) the exposure to BC in the city center. Urban planners could use this valuable information to project new cycleways, which would lead to healthier active transportation. Synchronizing traffic signals might further reduce exposure at intersections.
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•We monitored traffic-related pollutant concentrations while cycling in Curitiba.•BC, PNC, PM2.5 and VOC exposure showed high spatio-temporal variability.•Proximity to signalized intersections, bus stops and deep canyons increased exposure.•The impact of traffic calming areas on particle pollution is inconclusive.•Switching from diesel to electric buses may largely reduce cyclists' exposure to BC.
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.
Public transit plays a significant role in the sustainability of an urban region which requires high pedestrian safety at the interchange points. This research studies the magnitude of pedestrian ...collisions in the proximity of Public Transit Access Points (PTAPs) and address how Traffic Calming strategies and road elements improve pedestrian safety at PTAPs. Getis-Ord Hotspot Analysis and the Negative Binomial models are applied to address research questions. Pedestrian collisions occur more frequently at intersections with the presence of a PTAP and with a higher volume and number of bus routes. Traffic calming strategies such as road width reduction, sidewalk width increase, median refugees, pedestrian crossing phase, and vehicle stop signs could improve pedestrian safety of PTAP. Besides, pedestrians are at more risk in PTAP at locations where high road gradients and in proximity to intersections with a higher number of directions of vehicle traffic flow.
Road safety is a worldwide issue, while urban roads account for a high share of serious road injuries, especially involving vulnerable road users, such as pedestrians or cyclists. Specifically, the ...safety of major roads through built-up areas (through-roads) is insufficient due to mixed traffic conditions including vulnerable road users, varying driving behaviour, and many disruptions, which are combined with excessive speed.. In this context, various traffic calming measures have been implemented to improve road safety, such as gateways or pedestrian refuge islands. However, the specific safety impacts of traffic calming combined with specific characteristics of through-roads are often unknown, since most traditional evaluations have been limited by small sample sizes of crash data, as well as wide variations in physical and road characteristics. To overcome the limitations of crash-based evaluations, we used the GPS-based data from a sample of 21 Czech and 12 Polish through-roads to develop the Speed-Safety Index, which combines speed, speed variance, and traffic volume. Our study has three novelty features: (1) To assess safety, we used speed and speed variance simultaneously. (2) To complete the missing link between specific traffic calming measures and safety, we validated the statistical relationship between the developed Speed-Safety Index and crash history. (3) To prove the usefulness of the developed index, we also showed its practical interpretation by proving the effect of spacing between traffic calming measures on safety. The index proved to be well correlated to crash frequency and it also proved the effect of spacing between traffic calming measures: the longer spacing, the smaller speed-reducing effect. The paper concludes with a discussion on the limitations, which we plan to address in further research, by moving from the current macro-perspective (Speed-Safety Index on the level of through-roads) to the micro-perspective (focusing on individual directions, locations, and traffic calming measures). We also plan to investigate the method’s applicability in different contexts. If the approach proves feasible, with reliable and valid results, it may become an alternative for a proactive network-wide road assessment, as called for by the European Road Infrastructure Safety Management Directive.
Traffic calming measures (TCMs) are implemented in urban areas to reduce vehicles’ speed and, generally speaking, results are obtained. However, speed is still a problem in rural roads crossing small ...villages without a bypass and with short-length urban areas, since drivers do not normally reduce their speed for that short segment. Hence, various TCM can be installed. It is necessary to maintain a calm area in these short segments to improve road safety, especially for pedestrian aiming to cross the road, and to save combustible by avoiding a constant increase-decrease of speed. Four villages were selected to evaluate the efficiency of radar speed cameras and panels indicating vehicle’s speed. Results showed that the presence of radar speed cameras reduces the speed in the direction they can fine, but with a lower effect in the non-fining direction. Additionally, a positive effect was observed in the fining direction in other points, such as pedestrian crossings. Nevertheless, the effect does not last long and speed cameras may be considered as punctual measures. If the TCMs are placed far from the start of the village they are not respected. Hence, it is recommended to place them near the real start of the build-up area. Lastly, it was verified that longer urban areas make overall speed decrease. However, when drivers feel that they are arriving to the end of the urban area, due to the inexistence of buildings, they start speeding up.
Residential areas in Malaysia face various traffic-related issues such as high traffic volume, speed and noise levels, despite the prevalence of road hump installations. This paper studies how the ...residents perceive the existing traffic calming installations as a measure to improve their living environment. Based on the questionnaire distributed and using Principal Components Analysis (PCA), this paper identified that the themes in the residents’ perceptions on traffic conditions centred around daytime traffic volume and light vehicle speed and noise, daytime heavy vehicle speed and noise, satisfaction with surrounding environment and importance of better traffic conditions for a better living environment. Themes in perceptions on road hump effectiveness were road hump characteristics, traffic volume and light vehicle noise, light vehicle speeds and heavy vehicle noise and speeds. Responses were mixed on whether road humps had improved one’s living environment by reducing traffic noise, volume and speeds.
•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.
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