## 4 Conclusions and Discussion  
To increase brake efficiency and enhance driving safety, the 3D dynamic frictional contact model was created to conduct a reliable analysis of tire-pavement friction. Through this method, the following conclusions were determined.  
First: increasing pavement elasticity could enlarge the tire-pavement actual contact area, providing tires with stronger grip.  
Second: slip ratio has the most significant impact on frictional behaviors during tire-pavement contact. However, under the same slip ratio, high elasticity significantly interferes with tire rolling in comparison to pavements of ordinary elasticity.  
Third: the braking force coefficient can be slightly raised by the distinct improvement of pavement elasticity. However, braking distance is sensitive to tiny variations in this coefficient, allowing anti-skidding improvements to be made in asphalt by remarkably increasing the pavement's elasticity.  
Pavement skid resistance, coupled with vehicle, tire and pavement surface layer, is a problem that includes factors such as aggregate hardness, pavement surface texture and stiffening of paving materials. Moreover, analyzed from the aspect of the tire, this issue also investigated the effect of tire inflation pressure; tread pattern and the physical and mechanical properties of tread rubber materials. In addition, investigated from the angle of tire-pavement coupling, it is a systemic problem that incorporates tire slip ratio, tire-pavement contact behavior, and even the appropriate friction law. Conventional methods focus upon macro and micro texture effects on the frictional properties of the tire, to decrease the skid resistance of asphalt pavement. Investigating the changes in skid resistance caused by altering the recoverable resilient deformation property of pavement is a new approach to increasing driver safety. This method can be used to facilitate tire grip and enhance braking performance. This paper investigates pavement skid resistance from the aspect of paving materials' moduli; tire-pavement friction coupled with pavement texture, heat transfer by coupled frictional behaviors, stiffness modulus, and water film effects will be discussed in future research.  
This work is financially supported by the 2014 Chongqing Higher Education Institution's Excellent Achievements Program (Major Project) (Theme: Warm mix, semi-flexible compound pavement Technology (KJZH14104)), 2015 Chongqing Higher Education Institution's scientific and technological research program (Theme: Research on the skid Resistance Performance of CRM asphalt pavement based on the tire-pavement kinetic friction test system (KJ1500508)), and the 2016 National Natural Science Foundation of China (Tire braking-oriented anti-skid mechanism and estimating model of friction coefficient of asphalt pavement, No. 51608085). [PERSON] was in charge of the whole research program; [PERSON] built the trial protocol; [PERSON] and [PERSON] performed the experiments and data analysis. All authors discussed and contributed to the preparation and revision of the manuscript.  
The authors declare no conflict of interest.  
Figure 11: Pavement braking force coefficient under different slip ratios.