Study On The Evaluation Of Highway Alignment Consistency Based On Acceleration

In order to ensure traffic safety, rapid, economical, comfortable, highway alignment should have agood design consistency. Highway alignment consistency includes operating speed consistency, visionconsistency and acceleration consistency, and the consistency of highway alignment can adapt to thedriver’s expectations. The the evaluation of highway alignment consistency in the current rules andguidelines is based on operating speed, by calculating the analysis section’s operating speed difference. Infact, the acceleration consistency determines the operating speed consistency and the vision consistency ina certain extent. The size of the vehicle acceleration reflects the change of its running speed and impacts onthe driver and passengers’ mental and physical comfortable feeling directly, moreover, the value of speedaffect the driver’s vision and horizon. Using acceleration evaluate the highway alignment consistency willbe more direct and effective.At the basis of summing up the literatures, using the medium of acceleration, analyze the factors thataffect the acceleration in the people-vehicle-road-environment system, and put forward the followingindicators to evaluate highway alignment consistency: vehicle driving safety(including vehicle power andbraking), the driver’s mental and physiology comfortable feeling(including axial acceleration comfort,vertical acceleration comfort, lateral acceleration comfort, the changing rate of lateral acceleration comfort),environmental protection which based on Eco-Driving(including fuel consumption and exhaust emissions).Research on the relational threshold between acceleration and each evaluate indicators, based on AHP,calculated the weighting coefficient of each evaluation indicators. Combined with highway speedprediction model, vehicle features and physics related theory, establish the relationship betweenacceleration and highway alignment, to predict vehicle axial acceleration, vertical acceleration, lateralacceleration and the changing rate of lateral acceleration, and obtain the highway acceleration predictionmodel. Proposing highway alignment consistency evaluation index grade which based on the acceleration,deduce the evaluation index computing method of each evaluation indicators, and put forward anevaluation methods of highway alignment consistency based on acceleration finnaly. The evaluationmethods will provide the basis for the safety evaluation at the highway design phase, and reduce the trafficsafety problems caused by highway alignment design inconsistency.