Continuous Long Slope Road Alignment Research Based On Driver’s Factors

In recent years, continuous long slope roads appear a series of segments where accidentsare facile to happen, the tradition road alignment design theory on the base of vehicledynamics is exposing more and more drawbacks for guiding the alignment design of thecontinuous long slope segments.This study, from the driver’s view, attempts to research the influence of alignment ofcontinuous long slope segments on drivers in order to propose more reasonable and safetycontinuous long slope roads alignment. The research results are valuable to improve thetraditional design theory of continuous slope roads alignment, provide the referencesuggestion to modifying the current standard; the research results are also useful in inspectingthe continuous long slope road which is on the point of construction or has existed for running,finding out the black point, so safety measures can be taken in time.Under the guide of above ideas, actual vehicle tests are used as a mean to obtain researchdata. Nine drivers, age and driving experience are representative, are random selected as theresearch object of study; Acquisition of the drivers’ physiological indexes is by thephysiological recorder; GPS is used to get the real-time speed of actual vehicle tests, andmark some special events. Based on the collected data, using the corresponding statisticalanalysis method, relevant regression analysis models are built. Heart rate increase rate andspeed increase rate are first used as the characterization factors for drivers’ physiologyreaction and vehicle speed.The results of horizontal alignment research: Every plane curve is divided into sevensections, research the relationship between driver heart rate increase rate of each curvesection and the radius, put forward suggested value of curve radius based on the researchresults for long slope sections; The ratio of circular curve length with the curve length asindexes, study the regulation of drivers’ heart rate increase rate,and put forward the suggestedratio; Study the regulation between drivers’ heart rate increase rate and easement curve, putforward the suggested value of easement curve; Study the relationship between driver’s heart rate increase rate and the ratio of radius with plane curve length, establish related model, andpoints out the most unfavorable ratio.The results of longitudinal alignment research: Research the relationship between thedrivers’ heart rate increase rate and the difference of slop, puts forward the suggesteddifference of gradient which is unsafely; Study the relationship among slope, drivers’ heartrate increase rate and speed increase rate, the research result shows drivers’ sensitivity toslope is weak for downhill direction; For uphill direction, the traditional design theory,whichsuggests that between two steep slope should have a gentle slope may not be unsafe; Theresearch also get the relationship between speed increase rate and the slope length,therelationship between vertical curve radius and speed increase rate.By applying the polynomial regression method, models think about the horizontalalignment, longitudinal alignment, drivers’ heart rate increase rate and speed increase rate areestablished.Based on the above research conclusion, combined with the accident investigation data, atraining model of BP neural network is built, and reliability the model is tested, whichconfirm the above research results are reliable. In addition, the model also provides a reliablemethod in road safety evaluation of long slope sections in designing phase, modifying thedesign results in time.