## Hydroplane Speed on Flooded Highway

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brian
Posts: 506
Joined: Tue Jul 14, 2009 10:52 am

### Hydroplane Speed on Flooded Highway

Q: I'm looking for any literature or other references that address hydroplaning. I'd like to know how to do a hydroplane speed analysis.
A: The following is from our book McHenry Accident Reconstruction in the section Vehicle Control Factors: (a list of references is also below)
Hydroplaning OR Hydrodynamic Drag?
Dynamic hydroplaning occurs when the amount of water encountered on the roadway by a rotating tire exceeds the combined drainage capacity of the tread pattern of the tire and the texture of the pavement. The mass and viscosity of the water cause it to resist being displaced from between the tire and the pavement, thus generating lift forces on the tire which reduce tire contact with the pavement. When the lift forces are sufficient to completely support the load on the tire, contact with the road is no longer made and full dynamic hydroplaning is said to occur.
Prior to the onset of full tire hydroplaning, a transitional condition occurs in which the surface contact area of the tire footprint is decreased as the vehicle speed is increased. This condition is sometimes referred to as “partial hydroplaning” and it is associated with a reduction in the effective friction coefficient. The capacity of the tire tread grooves for water flow is an important factor in limiting the development of partial hydroplaning. Thus, at a given operating condition on wet pavement, the effective friction coefficient is reduced by worn tires.
The following physical factors are involved in the occurrence of hydroplaning of automobile tires:
• • Tire construction type, size and aspect ratio
• Inflation pressure
• Pavement surface texture
• Water depth
• Length of path in standing water
• Vehicle speed
Dynamic hydroplaning of automobile tires occurs on relatively thick water films, generally greater than 0.080 INCHES deep, and at speeds greater than 40 MPH (e.g., Ref. [1], [2], [3], [4] e.g., see Figure 1 from Ref. [1] and Figure 2 from Ref. [2]). A path length of at least 30 feet is generally required to have a significant effect on vehicle control (e.g., Ref. [3]. [4, [5]). The decrement of effective friction with vehicle velocity is depicted in Figure 3 from Ref. [2], and the decrement with tire wear is depicted in Figure 4, also from Ref. [2]. The analytical/simulation task is complicated by the fact that at speeds above approximately 30 MPH, the front tires will generally have cleared the track of water for the rear tires (e.g., Ref. [3],[4]).
Figure 1 Hydroplaning Speeds vs. Small Water Film Thickness, from ref [1]
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Figure 2 Susceptibility of some ground vehicle to hydroplaning (From Ref. [2])
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Figure 3 Curves of the coefficient of friction for different velocities and water depths, Tire 5.60-15, Load 551 Lbs, Tread 100%, P=22 PSIG (Note: 0.5 mm=0.02 in, 1.0 mm=0.038 in) (Ref. [2])
hydro3.jpg (64.48 KiB) Viewed 4479 times
Figure 4 Effect of tread pattern groove depth on braking grip, “flooded” road conditions (Ref. [2)
hydro4.jpg (42.6 KiB) Viewed 4479 times
REFERENCES:
• 1 Huebner, R.S., Reed, J.R., Henry, J.J., “Criteria for Predicting Hydroplaning Potential”, Journal of Transportation Engineering, Volume 112, No. 5, Sept. 1986.
2 Clark, S. K., editor, Mechanics of Pneumatic Tires, U.S. Dept. of Transportation, NHTSA, 1981
3 Ivey, D.L., Mounce, J.M., “Water Accumulations”, Chapter 6 of The Influence of Roadway Surface Discontinuities on Safety, Transportation Research Board, National Research Council, Washington, D.C., 1984.
4 Navin, F., “Hydroplaning and Accident Reconstruction”, SAE Paper No. 950138.
5 Hight, P.V., Wheeler, J.B., Reust, T.J., “The Effects of Right Side Water Drag on Vehicle Dynamics and Accident Causation”, SAE Paper No. 900105
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brian
Posts: 506
Joined: Tue Jul 14, 2009 10:52 am

### Re: Hydroplane Speed on Flooded Highway

Q: (rcd via email 10/11/10) I have three questions related to hydroplaning:
• 1. Is there any relation between hydroplaning and stripping in asphalt concrete?
2. When the hydroplaning phenomena happens,what kind of damages will occurre in the pavement body?
3. Do you have any recommend for studying in this field?
A:
• 1) when roads are "stripped", if you mean removal of pavement material, generally longitudinal scrapes are included and/or peaks/valleys in the pavement are created which would provide avenue for water to escape from the tire/road interface thereby reducing the chances of hydroplaning for all other things being equal between 'normal' road and a stripped road. If on the other hand you mean 'pavement stiping' as in marked with paint or plastic material for paint lines or temporary construction zone lines on pavement, the potential blockage of flow passeges in the pavement could cause a possible increase in hydroplaning effects for very localized areas. However you generally you need 30 feet (10 m) or so of length and paint lines are 4 inches wide so most tires are twice or more as wide so the effect would be minimimal. We have seen some indications of possible problems with motorcycles but mainly in the friction variation for dry roadways.
2) I am not sure what you are asking? No damage occurs to the pavement. The tire doesn not contact the roadway and thereby rides on a 'sheet' or water.
3) i would recommend you start with the previous references of this thread Hydroplane Speed on Flooded Highway
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MSI
Posts: 1301
Joined: Thu Jun 18, 2009 12:37 pm

### Re: Hydroplane Speed on Flooded Highway

June 2019: Recent post by Wade Bartlett to the FACEBOOK page for NAPARS on hydroplaning included references and the following list:
• 1. Hydroplaning in a straight line allows tires to spin down.
2. That speed is higher than the hydroplane speed under braking.
3. Full-depth new tires essentially can't hydroplane.
4. All else being equal, fronts will hydroplane first and clear a path for the rears.
5. Bald tires can be expected to hydroplane on standing water in the mid 40s mph.
6. (added late) higher inflation pressures mean higher contact pressures and lower hydroplane propensity.
Further reading can be found in these sources:
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