In this paper, the reasonable relevant parameters of approach road in truck escape ramp are proposed by using the combined method of investigation and academic analysis. Firstly, representative vehicle type and design speed are determined by traffic investigation on a long and steep downgrade mountain road in Chongqing city. Then the length and angle of approach road are studied deeply based on its practical functions and uses. The influence mechanism of the approach road's length on drivers both in psychology and physiology is researched to determine the length of approach road. The angles between approach road and mainline are calculated at different horizontal radii. Besides the radii of horizontal of mainline, some other factors are comprehensively considered, such as the lateral stability of vehicle, as well as the geometrical characteristic of vehicles' orbit on the approach road of truck escape ramp.

An experimental design was used to study the vehicle operation characteristics of different ramp entrance conditions in underground road. With driving simulator, the experimental scenarios include left or right ramp with first, second and third service level, respectively, to collect vehicle speed, acceleration, lateral displacement and location information at the ramp entrance section. By using paired t-test and ANOVA, the influence factors of vehicle operating characteristics are studied. The result shows that effects of ramp layout and mainline traffic environment on vehicle operation characteristics are significant. The regression model of vehicle traveling distance on acceleration lane is established. Suggestions are made for ramp entrance design of underground road.

Road administrator should understand the condition of road traffic facilities to improve traffic efficiency and ensure driving security. In the paper, a new evaluation method of road traffic facilities was proposed. By using fuzzy AHM (Analytic Hierarchy Model) method in synthesis evaluation, a reasonable safety evaluation model was established. First, the index system was established by comprehensively considering all kinds of facility attributes, including target layer—safety of road traffic facility, first level layer—4 parts of road traffic facility, second level layer—eighteen relevant indexes. Then the measure to judgment matrix was built on the combination of AHM and expert evaluation. The evaluation of what level the road traffic facilities belonged to was made out by the fuzzy mathematic. The feasibility and validity of the approach were verified by an engineering practice in the end and the advantages of the method proposed in this paper were pointed out.

At present, the safety evaluation of the road is often concerned with historical crashes. Nevertheless, it is difficult to effectively evaluate the safety of the road before its reconnaissance, design and construction. With the continuous development of driving simulation technology, it has been widely used in safety assessment of proposed roads; but, an effective safety evaluation model is still needed to standardize this process. Based on a full-scale driving simulator, the research virtualizes the scene of the Wuliu highway. Generating a virtual highway consistent with the geometric conditions of the Wuliu highway, driving data was collected in the driving simulator and the driving situations of different sections were analyzed.. The aim is to identify accident-prone sections and establish an evaluation system for comfort, as well as safety, from both the subjective and objective points of view. The objective safety evaluation includes seven kinds of indexes. The subjective safety evaluation of the road includes an evaluation of agreeableness, comfort and consistency. Based on the Analytic Hierarchy Model (AHM) method, the safety level of the road can be calculated. Furthermore, the method will play a significant role in highway construction and operations management in the future.