Background and objectivesRoad traffic accident (RTA) in the Kingdom of Saudi Arabia (KSA) is the first and major cause of death. The primary objective of this paper is to investigate the impact of Saudi Vision 2030 on road traffic safety. The Vision 2030 programs lead to the implementation of two crucial steps. The first step was to introduce value-added tax (VAT), and the second step was to increase fuel prices. The effect of these two steps on RTAs, injuries, and fatalities is determined and evaluated in this study.Research methodsThe data of RTAs, injuries, and fatalities in the last three decades before implementing VAT and before increasing fuel prices were collected and analyzed. A short-term effect of fuel prices was evaluated using the data of 3 months after each increase in fuel price. The results of RTA before the increase in fuel prices were compared with those of RTAs after the increase in fuel prices. Time series autoregressive and t-test were used to analyze the significant differences in the results.Results and discussionThe results show that RTAs have increased continuously during the last 30 years until the increase in fuel prices. A short-term effect of Vision 2030 and economic transformation were evaluated using RTA data before and after the increase in fuel prices. The remarkable decline in the number of RTAs, injuries, and fatalities after fuel prices increased was recorded.ConclusionDespite all the core issues implementing to reduce RTAs, such as traffic law enforcement, RTAs in the KSA increase and become the first cause of death in the country. Vision 2030 leads to an increase in gasoline prices and the implementation of VAT. The increase in gasoline prices contributes to a short-term decrease in RTAs, injuries, and fatalities by 22.4%, 21.9%, and 14.1%, respectively, while intermediate-term decrease in RTAs and road traffic fatalities is by 72892 and 1842, respectively. The decrease in RTAs may be attributed to the reduction in unnecessary trips and slower and careful driving by people to decrease fuel consumption. Statistical analyses performed using time series and t-test confirmed the significant effect of fuel prices on reducing RTAs.

Producing high-strength self-compacting concrete (SCC) requires a low water-cement ratio (W/C). Hence, using a superplasticizer is necessary to attain the desired self-compacting properties at a fresh state. The use of low W/C results in very brittle concrete with a low deformation capacity. This research aims to investigate the influence of crumb rubber (CR), fly ash (FA), and nanosilica (NS) on SCC’s workability and mechanical properties. Using response surface methodology (RSM), 20 mixes were developed containing different levels and proportions of FA (10–40% replacement of cement), CR (5–15% replacement of fine aggregate), and NS (0–4% addition) as the input variables. The workability was assessed through the slump flow, T500, L-box, and V-funnel tests following the guidelines of EFNARC 2005. The compressive, flexural, and tensile strengths were determined at 28 days and considered as the responses for the response surface methodology (RSM) analyses. The results revealed that the workability properties were increased with an increase in FA but decreased with CR replacement and the addition of NS. The pore-refining effect and pozzolanic reactivity of the FA and NS increased the strengths of the composite. Conversely, the strength is negatively affected by an increase in CR, however ductility and deformation capacity were significantly enhanced. Response surface models of the mechanical strengths were developed and validated using ANOVA and have high R2 values of 86–99%. The optimization result produced 36.38%, 4.08%, and 1.0% for the optimum FA, CR, and NS replacement levels at a desirability value of 60%.

Generally the methods were used to characterize soil contamination include collecting samples of soil then analyzing them to recognize contaminates in the laboratory. Commonly, this method of characterizing the contamination of a soil system is the only one agreeable to regulatory societies. However, sample analysis in the lab faces important problems such as soils sampling is really time consuming and costly, sampling is not constant with time and the samples be able to contaminate through sampling and carrying to the lab. Thus several geophysical techniques have been developed which used the dissimilarity in the soil physical properties after soil contamination. Dielectric technique shows high conceivable for characterization diesel contaminated soil. Further use of this technique; rely upon the availability of information about the dielectric properties of the contaminated soil. In this study, the effects of induced by a diesel presence in an unsaturated soil, on the complex dielectric properties were sought. It has been shown experimentally that the diesel presence in an unsaturated soil is traduced by an increase of both dielectric constant and loss factor. A comparison with the existing results in this study and in the literature for saturated soils shows an opposite effect on the complex dielectric properties. The importance of the influence induced by the diesel on the dielectric properties of an unsaturated soil was noticed and compared to a saturated soil. On the basis of the theoretical dielectric mixture models, a justification to these opposite behaviors and their importance has been presented and various models for the two cases have been developed.

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This paper presents the development of an electromagnetic probe to accurately measure the soil electromagnetic properties such as dielectric constant and loss factor in the field. The in-site dielectric probe sensor is designed and methods have been developed to calibrate and validate the accuracy of the sensor in measuring dielectric properties of the material. Clean saturated sandy soil material with porosity 40% was used. The soil samples were contaminated by leachate from municipality solid waste from the landfill site. Five levels of leachate contamination were prepared, ranging from 0% to 10%. Dielectric properties of soil polluted sample were measured using the proposed in-site dielectric sensor. Dielectric properties of contaminated soil were evaluated at a different frequency and leachate content. The result showed that both dielectric constant and loss factor decree with increasing frequency due to the reduction of conductance current at high frequency. Also, the result showed that the dielectric properties of leachate-contaminated soil decrease with increasing leachate content while the loss factor increase with increasing leachate content. Mathematical models were developed to determine the relationship between soil dielectric constant, loss factor and soil leachate pollution content.