Objective: This study aimed to explore the relationship between crash types and different freeway segments and identify the factors contributing to crashes on different freeway segments. Unlike most of the previous studies on freeway segments, this study separately investigates basic freeway segments, single ramp influence segments, and multiple ramp influence segments.
Methods: Nonlinear canonical correlation analysis (NLCCA) and proportionality test were used to identify the relationship between crash types and different freeway segments. The data sets for the different freeway segments accumulated for this study consist of 9,867 crash samples with complete information on all 22 chosen variables. A multinomial logit model (MNL) was used to estimate the influence of crash factors on different freeway segments.
Results: The results show that weaving and diverge overlap influence segments (WD) are more likely to have injury or fatal crashes; diverge and diverge overlap influence segments (DD) are more likely to have property damage–only (PDO) crashes; merge and merge overlap influence segments (MM) are more likely to have sideswipe crashes; and WD have non-sideswipe crashes; WD and weaving overlap influence segments (MW) are more likely to have rear end crashes; and MM segments are less likely to have hit object crashes. The contributing factors are identified by MNL and the results show that different traffic variables, environmental variables, vehicle variables, driver variables, and geometric variables significantly affected the likelihood of crashes on different freeway segments.
Conclusions: Investigation of crash types and factors contributing to crashes on different freeway segments is based on multiple ramp influence segments, which can promote a better understanding of the safety performance of various freeway segments. 相似文献
Environmental Science and Pollution Research - Wet flue gas desulfurization technologies have received much concern for their superior performance on co-controlling the acid gases and mercury.... 相似文献
The industrial sector is usually the largest economy sector for carbon emissions in many countries, which made it the sector with greatest potential for carbon reduction although the process duration might be very long. Studying the potential of industrial emission reduction has great significance in estimating the carbon emission peak of China on the one hand, and adjusting its strategy in international climate change negotiations. By employing the economic accounting method, this article estimates the emission reduction potential of China’s Industrial sector for the period of 2010–2050. It reveals that, taking 2030 as the year when the emission reaches the peak, the total reduction can be 8.38 billion tons (bts) for the period of 2010–2030, with 3.12 bts from structural reduction while 5.26 bts from intensity reduction. Afterwards, reduction will continue with a total amount of 6.59 bts for the period of 2030–2050, where the structural reduction accounts for 2.47 bts, and intensity reduction 4.115 bts. If both industrial and energy consumption structures are improved during the above period, the reduction potential can be even greater, e.g. the emission peak can arrive five years earlier (in the year of 2025) and the peak value can decline by about 8% as compared to the original estimation. Reviewing the trajectory of emission changes in developed countries indicates that the industry sector can contribute to the overall reduction targets through the dual wheels of structural reduction and intensity reduction, even beyond the emission peak. This article concludes with the following policy suggestions. (1) Our estimation on the emission peak of the industrial sector suggests that China should avoid any commitment earlier than 2030 on the timeline of the overall emission peak; (2) the great potential of industrial emission reduction can improve the situation of China in climate change negotiation, where the intensity reduction can serve as an important policy option. (3) Reduction potential can be further enhanced through technology advancement, which requires furthering of market oriented reforms and improvement of institutional design. (4) To secure the reduction effects of the industrial structure adjustment, the balanced development among different regions should be encouraged in order to avoid the reverse adjustment caused by industrial transferring. (5) International cooperation promoting the application and development of industrial emission reduction technologies, including carbon capture, utilization and storage, should be encouraged. 相似文献
Temporal and spatial changes of total nitrogen (TN), total phosphorus (TP) and chlorophyll-a (Chl-a) in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 μg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN:TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4+ loading from eight major tributaries were in the range of 1.56×104-5.47×104 and 0.19×104-0.51×104 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu. 相似文献
With the production of crude steel, China produces several million tons of sintering dusts which contain a great deal of valuable metals such as, K, Na, Zn, Pb. If discharged directly without adequate treatment, these elements can lead to adverse effects on the environment. Therefore, it is very necessary to determine how to separate these elements from the dust before discharge. Several physical and chemical detection methods were used to study the basic properties of sintering dust. At the same time, preliminary experiments on the recovery of the potassium resources from the sintering dust were carried out. The mean particle size of the electrostatic precipitator (ESP) dust determined by a laser granulometer was 41.468 μm. Multi-point BET and single-point BET analysis showed that the surface area of the ESP dust was 2.697 m2/g. XRD measurements detected the following phases in the ESP dust: Fe2O3, Fe3O4, KCl and NaCl, and Fe2O3, Fe3O4 and SiO2 in the water-washed dust. SEM-EDS results proved that in the ESP dust, K mostly existed in the form of KCl particles without being coated. Leaching experiments showed that the KCl in the ESP dust could be separated and recovered by water leaching and fractional crystallization. Through the recovery experiments, the yield of K-Na vaporized crystalline salt was 18.56%, in which the mass fractions of KCl, NaCl, CaSO4 and K2SO4 were about 61.03%, 13.58%, 14.03% and 9.97%, respectively. This process is technically viable and considerable in economic benefit. There was almost no secondary pollution produced in the whole recovery process. 相似文献