How fast do you have to drive to hydroplane?

Question

Does it depend on how much water is on the groud?

Currently I'm in Oakland, Ca and the bay area is being hit by the worst storm in 5 years (says the CBS news) and people can't stop driving crazy!

Someone died in San Jose on highway 17 and the San Rafael bridge was closed because of an overturned truck.

It's raining over 7 inches an hour and people can't stop speeding!

How fast would someone have to drive to hydroplane? Why hasn't the CHP posted or announced a lower speed limit?

Answer 1

ive hydroplaned on my bicycle before. about 15 mph

Answer 2

I found this article on a website:

It is a pretty safe bet to assume that any speed in excess of 60 MPH is fast enough to support hydroplaning regardless of the other variables. This is not to say that at 55 MPH you are safe, however. (A formula that comes close to predicting the speed at which you will hydroplane, assuming at least .2" of water on the ground, is: 10.27 * Sqrt(tire pressure) which shows that if your tires hold 35 psi, hydroplaning can be expected at 60.76 MPH,

Answer 3

chp is hoping that people would use common sense and drive slower but 30 mph you can but easier to correct than if your going 70 mph.

Answer 4

way too many variables here, how much does the vehicle weigh? how wide are the tires? how much tread depth? how many tires on the vehicle?(1 ton dually/standard 4 tired vehicle /motorcycle) how deep is the water?

Answer 5

Speed and water depth are only two factors.  Condition of tires and type of vehicle are other important considerations.  Personally, when the weather is bad (snow is more prevalent here) a good rule of thumb is to slow down at least 5-10 mph under the speed limit and increase following distance fourfold.  Of course that doesn't stop other people from driving like idiots around you so if you can, take more residential routes or slower through streets and stay off the freeways.

Good luck!