Research On Freeway Optimal Design Based On The Forgiving Concept

Since the1980s, the freeway construction has developed rapidly in our country, however,the number of traffic accidents and casualties happened on the freeway every year are stillkeep at a high level, causing serious harm on the social economic development and people’slives. Road design in our country uses design speed as a general principle which based theidea of Car-oriented, without taking the physiological characteristics and behavior habits ofthe driver into consideration. However, the driver will make the wrong judgment and actionunavoidable in some unexpected situations, which may cause traffic accident, bring aboutheavy casualties and economic losses. We should not be asking too much that every drivercan make to emergencies are calm, accurate and rapid judgment, obviously this is unrealistic.The forgiving concept is based on the people-oriented, fully considering the driver’sphysiological characteristics and driving habits, it starts from road design itself, throughtechnical means to actively guide the driving behavior of the driver and correct the deviation,while providing certain tolerance space when the driver make mistakes, maximize theprotection of the driver’s safety. This article is based on the tolerance idea to study3aspectson freeway optimization design method from alignment optimization, initiative induction andstrengthen tolerance.On the basis of K5+000~K19+000in Beijing-Xinjiang freeway from Jiao Niwan to theborder of Hebei and Shanxi, the whole road is divided into20units according to thecharacters of the route and the characteristics of the VISSIM software built-in model, collectoperating speed of the whole route using VISSIM, and get the operating speed of each sectionunit and using the operating speed to check alignment consistency, at last use technical means todisposal section that is not in conformity with the requirements.Based on the forgiving concept, this paper introduces several kinds of forms in lackingactive guiding measures exists on the freeway in our country at present, This paper putsforward some measures such as visual induction, speed control, and reduce the driver’s visionto strengthen highway itself for the driver’s active guidance function, strengthen the securityof driving.Through the study in the theory of roadside safety design on foreign countries, in theview of forgiving design and ditches forgiving design, present design idea in roadside designwhich is suitable for China’s national conditions in the slow slope design and smooth design,calculate Hydrology and Hydraulic in the forgiving ditches.The application of forgiving concept in the freeway design can find the bad alignment design specifications and security risks, provide initiative induction that meet the drive’s psychological andphysiological characteristics, provide certain tolerance space when the vehicle lost control, and it hasimportant practical significance for freeway traffic safety.