This article examines the relationship between travel speeds and crashes on two-lane highways, accounting for traffic exposure and road infrastructure characteristics. The study's database included ...179 road sections in Israel, which included free-flow travel speeds, 3-year injury crash data, traffic volumes, and road infrastructure characteristics. Preliminary analyses of in-data correlations supported the selection of appropriate speed and infrastructure indicators. Homogeneous groups of road sections were identified according to their characteristics. Negative binomial statistical models were fitted to injury crash counts for day and night hours, using speed indicators, section length, traffic volume, and the homogeneous road groups, which reflected various road design conditions. The models demonstrated a positive relation between mean speeds and crashes, while controlling for traffic and road characteristics. The expected crash change following higher travel speeds was more substantial for night hours. In line with previous research, section length, traffic volume, and worse road design were positively related to crashes.
In order to control the deformation of surrounding rock in deep high-stress and intense-mining roadways, taking a deep coal roadway with continuous deformation as an example, the characteristics of ...crustal stress, coal strength, and mining influence of roadway are obtained by underground tests. The combined failure mechanism of coal roadway surrounding-rock is revealed by differential stress of deep and shallow anchor cables. We propose that the improvement of surrounding rock control for coal roadway is adopting the coupling control technology of anchoring and unloading. The stress distribution and evolution laws of lateral surrounding rock of unloading holes are obtained by numerical simulation and theoretical calculation, and reasonable unloading-hole spacing of 4.0 m is comprehensively determined. A mechanical model of roadway roof beam under fixed support at both ends is constructed and the important role of anchor cable beam-truss in controlling the stability of coal roadway is obtained. The rationality of coupling control technology of anchoring and unloading and parameters has been verified by engineering test and mine pressure observation, providing technical references for surrounding rock control in deep intense-mining and large-deformation roadways.
Abstract
Indonesia strives for toll road connectivity to push the high logistics costs and lead to economic growth. However, the expansion of toll road construction on a large-scale has cost much ...money. So, an innovative funding scheme must be developed to attract the private to invest in those projects. Hybrid Annuity Model is a new public-private partnership developed by the Government of India in 2016 to reduce concessionaires’ risk on toll road project funding. This study aimed to examine the compatibility of the Hybrid Annuity Model implementation on Indonesia toll road. The analysis was carried out through financial feasibility and sensitivity analysis on Serang – Panimbang toll road as the object study. Moreover, a survey was conducted to know the stakeholders’ perception of this funding scheme implemented in Indonesia. The results showed that Hybrid Annuity Model could give financial feasibility on Serang – Panimbang toll road under any changes of traffic volumes, toll fares, discount rates, investment costs, investment return period, and the investment proportion between the Government and the concessionaires. From stakeholders’ perspective, Hybrid Annuity Model could be implemented on Indonesia toll roads, especially those which were not financially feasible and located in rural areas. Furthermore, it needed some improvements and supporting regulations to be more suitable applied on Indonesia toll road.
Based on the demand of vehicle emission research and control, this paper presents the development of a portable vehicle measurement system (PEMS) based on SEMTECH-DS and ELPI+, the vehicle emission ...tests carried out on actual roads, and the data obtained for the establishment and validation of a vehicle emission model. Based on the results of the vehicle emission test, it was found that vehicle driving conditions (speed, acceleration, vehicle specific power (VSP), etc.) had a significant impact on the pollutant emission rate. In addition, local driving cycles were generated and the frequency distribution of VSP-bin under different cycles was analyzed. Then, through the establishment of an emission rate database, calculation of emission factors and validation of the emission model, a vehicle emission model based on actual road driving conditions was developed by taking VSP as the “surrogate variables”. It showed that the emission factor model established in this study could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. Through this study, it could be found that due to the great differences in traffic development modes and vehicle driving conditions in different cities in China, the emission model based on driving conditions was a better choice to carry out the research on vehicle emission in Chinese cities. Compared with directly applying international models or quoting the recommended values of relevant macroscopic guidelines, the emission factor model established in this study, using actual driving conditions, could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. In addition, due to the rapid development of China’s urban traffic and the rapid change of driving conditions, it was of great significance to regularly update China’s urban conditions to improve the accuracy of the model, no matter which model was chosen.
Roads and road tourism loom large in the Australian imagination as distance and mobility have shaped the nation's history and culture. This book explores how Australians have experienced and imagined ...roads and road travel over time and offers a new way of thinking about roads and road tourism as important strands in a nation's cultural fabric.
Current LCA-based environmental impact assessments rarely consider the environmental impact of traffic network deterioration due to temporary road closures during road infrastructure construction ...processes. This study proposes a quantification method to evaluate the environmental impact of traffic diversions during the road infrastructure construction process. The environmental impact assessment method ReCiPe 2016 was selected to evaluate the environmental impact of pollutant emissions from deteriorated traffic conditions. Ten types of traffic emissions were estimated by emission factors and traffic conditions. A case study quantified the potential environmental impact of traffic emissions resulting from four diversion plans based on an actual bridge-construction case study in Chongqing city of China. Results revealed that different diversion plans could lead to different final environmental impacts. “Global warming” dominated both “Human health” and “Ecosystems” impacts. In the “Human health” category, more than 95% of the environmental impact was contributed by global warming. Similarly, the impact of “Global warming” was higher than 75% in the “Ecosystems” category. CO2 emissions were the main contributor to the overall “Global warming” impact in all four diversion plans. The traffic speed under traffic diversions before and during road infrastructure construction processes is the major factor influencing the overall environmental impact (endpoint).
•Effects of lighting conditions on operating speeds on urban arterials are explored.•Random effects model to estimate the entire speed distribution along road sections.•Average speeds and deviations ...increase when illuminance increases.•At night-time, the considerable variation in speed due to driver behaviour.•Random effects often appear to be very low and sometimes negligible.
Operating speeds on roads are influenced by lighting conditions: indeed most of the driving tasks are influenced by visual information. In terms of supporting evidence, there is a significant volume of published research that demonstrates how safety is affected by road geometrics and environmental lighting conditions. However, only a few studies have investigated the contextual impact of these factors on driver speed behaviour, which in turn is considered one of the most important variables affecting road safety.
In this paper, speed distributions have been modelled using environmental parameters related to both road geometrics and lighting conditions. To achieve this, the authors compiled a comprehensive database in which geometric characteristics, speeds, illuminance and luminance are available for both night-time and daytime conditions. The results show that average speeds and deviations from the mean are significantly affected by changes in lighting parameters for the different conditions (sunny, cloudy, and dark) considered in this study. Knowing the effects of such parameters on operating speed is fundamental for effective road management policies, especially on urban roads where, notably, the highest number of accidents occur.
In this paper, an enabling multi-sensor fusion-based longitudinal vehicle speed estimator is proposed for four-wheel-independently-actuated electric vehicles using a Global Positioning System and ...Beidou Navigation Positioning (GPS-BD) module, and a low-cost Inertial Measurement Unit (IMU). For accurate vehicle speed estimation, an approach combing the wheel speed and the GPS-BD information is firstly put forward to compensate for the impact of road gradient on the output horizontal velocity of the GPS-BD module, and the longitudinal acceleration of the IMU. Then, a multi-sensor fusion-based longitudinal vehicle speed estimator is synthesized by employing three virtual sensors which generate three longitudinal vehicle speed tracks based on multiple sensor signals. Finally, the accuracy and reliability of the proposed longitudinal vehicle speed estimator are examined under a diverse range of driving conditions through hardware-in-the-loop tests. The results show that the proposed method has high estimation accuracy, robustness, and real-time performance.
The increasing importance of utilizing new technologies, such as GNSS (Global navigation satellite system) devices, total stations, drones, scanners, etc., in forestry has become evident with the ...development of these tools. Combined with precise GNSS devices, UAVs represent an efficient tool that facilitates field measurements and reduces time spent in the field while also providing highly accurate data. To accurately determine the application of spatial data for calculating the longitudinal slope of forest/logging roads in a research project, measurements based on UAVs were conducted and compared with GNSS data. GNSS data were considered the reference values for the studied area, assuming that satellite positions and internet signals were good. An accurate longitudinal slope was necessary to define fuel consumption on forest/logging roads and slopes throughout the project and to verify the calculation method that could be applied for such or similar terrain conditions and overgrowth. The main goal of this research phase was not to study fuel consumption but to obtain an accurate longitudinal profile of forest/skid roads on rocky terrain that is not overgrown or poorly grown. The study put forth two hypotheses, one of which was ultimately confirmed, while the other was refuted. The results show no significant differences when comparing the absolute elevation of the points in the profiles for defining the longitudinal slope of the road using the program for designing forest/skid roads. While applying such a method of data collection to create the main projects for the (re)construction of forest/skid roads, there are significant deviations in earthwork masses. There was a difference of over 22.64% in one of the types of earthwork excavation on the designed forest road, so the method implemented in the research does not give sufficiently accurate results.
Abstract
Geocell is a geosynthetic used in foundation works, road construction and slope reinforcement. This research on slope reinforcement with geocells was conducted in a landslide affected area. ...The case study is a landslide on an access road to a tourist area in East Java, Indonesia, which resulted in almost the entire road body collapsing. In this research, modeling will be carried out using the LEM (Limit Equilibrium method) method with geoslope software to determine the increase in the Safety Factor (SF) value. The results of the slope stability analysis in the condition without reinforcement resulted in an SF value of 0,585. Reinforcement planning was carried out with 3 models at a depth of 9.6 meters and using a 57°slope. Modeling 1, 2, and 3 respectively used geocell sizes with lengths of 1.5 and 4 meters, 1.5 meters and 5 meters, 1.5 meters and 6 meters. The results of the slope stability analysis in modeling 1, 2, and 3 resulted in SF values of 0.783, 0.912, and 1.027, which means that in this study the increase in SF value in direct backfill conditions without reinforcement compared to modeling 1, 2, and 3 was 33.85%, 55.90% and 75.56%.
