The assessment and grading of a highway landscape environment is the basic work of highway route layout and landscape planning, and it is also a key link to whether the highway can be integrated into the surrounding environment. This article analyzes the connotation and value standard system of highway landscape assessment and proposes a highway landscape environment assessment method that combines a quantitative assessment and a humanistic assessment. Consequently, a highway landscape environment assessment indicator system with landscape features, environmental harmony, visual environment and environmental carrying capacity as assessment contents is constructed. Finally, using the set-pair analysis method, an evaluation model for grading the quality of the highway landscape environment is proposed. The model divides the highway landscape environment into four grades and proposes highway landscape planning and design strategies under the conditions of different grades. The theory is applied in the landscape planning of the Xi’an-Baoji highway in China. The results show that the overall assessment of the total indicator is “Grade 2”, the environmental carrying capacity of the subsystem is “weak”, and the landscape quality is “good”. This theoretical approach combines discursive cognition with quantitative analysis to achieve a systematic and refined assessment of the highway construction environment.
The traffic flow of non-motorized vehicles on the highway segments crossing small towns is disorderly and chaotic. In order to improve the traffic environment and regulate the order of non-motorized operations, this article studies the spatial and temporal distribution and traffic flow parameters of non-motorized traffic on the highway segments crossing small towns. The non-motorized traffic within the section of the National Highway G310 crossing small towns in Henan Province, China, is investigated through various research tools such as questionnaires, interviews, and on-site statistics. The regularity and characteristics of non-motorized traffic in terms of travel purpose, travel distance, travel time, and travel frequency were obtained. Meanwhile, based on the actual collected traffic data, the speed–density relationship, flow rate–density relationship, and speed–distance relationship of non-motorized traffic flow were studied using mathematical and statistical methods. The results show that thresholds exist for both time and distance traveled by non-motorized vehicles on small town road sections. The threshold value of riding time is 30 min, and the threshold value of riding distance is 5 km. Under the free flow state, the speed distribution is near a certain desired speed, and the flow rate–density relationship conforms to the exponential function relationship when the flow rate is greater than the critical flow value. The speed and distance show a cubic function relationship, and the speed gradually increases with the increase in distance between the non-motorized vehicles and towns. Based on the results of the above analysis, it is possible to grasp the travel regularity of non-motorized cyclists on highway segments crossing small towns. This provides a theoretical basis for enhancing the efficiency of non-motorized travel and improving the non-motorized travel environment.
The high-temperature rheological properties of emulsified asphalt mastics have a significant impact on the service performance of cold recycled mixtures with asphalt emulsions. In this paper, a dynamic shear rheological (DSR) test and a multiple stress creep recovery (MSCR) test are carried out to analyze the influence of tunneling coal gangue powder (TCGP), portland cement (PC), limestone powder (LP), and four kinds of filler binder ratio (F/B) on the high-temperature rheological properties of emulsified asphalt mastics before and after rolling thin film oven test (RTFOT) ageing. Based on the principle of time–temperature equivalence and a viscoelasticity material model, the main curve of emulsified asphalt mastics under frequency scanning test is established, and the rheological properties of emulsified asphalt mastics in a wide frequency domain are analyzed. Finally, the grey entropy theory is used to quantitatively analyze the correlation between different high temperature performance evaluation indices of emulsified asphalt mastics. The results show that the RTFOT ageing process can significantly enhance the high temperature deformation resistance of emulsified asphalt residue and its mastics. The rutting factor (G*/sin) of emulsified asphalt mastics increases exponentially with the increase of F/B, while the phase angle is less affected. TCGP mastics and PC mastics have better high temperature performances than those of LP mastics. The most suitable range of F/B is 0.9~1.2 when TCGP is used as the filler, and 1.2~1.5 when PC or LP is used as the filler. Grey entropy correlation analysis shows that there is a good correlation between the two evaluation systems of the DSR test and the MSCR test, and both can evaluate the high-temperature performance of emulsified asphalt mastics.
Median U-turn intersection treatment (MUIT) has been considered as an alternative measure to reduce congestion and traffic conflict at intersection areas, but the required spacing between the U-turn opening and the intersection limits its applicability. In this paper, a U-turn design with Advance Left Turn (UALT) is proposed with the aim of addressing the disadvantages of insufficient intersection spacing and difficulty in the continuous vehicle lane change. UALT provides a dedicated lane to advance the turning vehicle out of the intersection and directly to the U-turn opening without interacting with through traffic. The effectiveness and traffic volume applicability of UALT was demonstrated through field data investigation, simulation and analysis with VISSIM software. The proposed design was evaluated in terms of three parameters: delay, queue length and the number of stops. The results show that when the traffic volume range of the main road is (1900, 2200) pcu/h and the traffic volume of the secondary road is more than 900 pcu/h, the optimization effect of UALT on both conventional intersections and MUIT is very significant. Taking a signal-controlled intersection in Zhengzhou City, China, as an example to build a simulation model, compared with the conventional intersection and MUIT, the delay drop is reduced by 73.48% and 41.48%, the queue length is reduced by 84.85% and 41.66%, and the operation efficiency is significantly improved.
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