Influence of thin water films over road surfaces on driving safety(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年05期
- Page:
- 168-175
- Research Field:
- 交通工程
- Publishing date:
Info
- Title:
- Influence of thin water films over road surfaces on driving safety
- Author(s):
- LUO Jing; WANG Yuanqing
-
- Keywords:
- traffic engineering; traffic safety; critical water film thickness; skid resistance coefficient; road surface thin water film; water film depth; road surface microtexture
- PACS:
- -
- DOI:
- -
- Abstract:
- The influence of a thin water film on traffic safety under rainfall was studied. By referring to the description of fluid lubrication in a Strybeck curve, the relationship between the tire and road surface with a thin water film was considered to conform to the typical state of a curve. Based on this, the contact between the tire and road surface when driving on wet pavements with a water film can be reflected by testing the change in the road surface friction coefficient under the state of the thin water film. Using a dynamic friction coefficient tester, the dynamic friction coefficient of different water film thicknesses was tested on three typical road surface test pieces with different texture depths. Based on the experimental observation data, a nonlinear regression model of the dynamic friction coefficient corresponding to the water film thickness at different sliding speeds was established, and a model curve was drawn. Based on this model curve, the concept and value of the critical water film thickness affecting driving safety were proposed. The critical water film thickness was used to reflect the approaching process from mixed lubrication to hydrodynamic lubrication of the tire on a road surface with a water film. The test results show that when the speed is 20, 40, and 80 km/h, the critical water film thickness is 0.48, 0.44, and 0.39 mm, respectively. At a certain speed, when the surface thickness of the water film exceeds the critical water film thickness, the risk of a viscous water slip significantly increases. Under the influence of a thin water film, the smaller the pavement structure depth, the faster the decrease in friction coefficient, and the lower the friction coefficient. In areas where rainfall has a more severe effect, pavement types with higher texture depth (pavements with coarse aggregate), can be more advantageous to the discharge of the water film between the tire and road surface, thus improving driving safety under the presence of a thin water film. 2 tabs, 8 figs, 28 refs.
Last Update: 2018-10-23