CleverRaven/Cataclysm-DDA — pull request #3507 by Petethegoat (2013-10-07 23:44:56+00:00)
Title: Adds a chance for vehicles to slip and skid in wet weather.

The chance is affected by the total wheel surface area.
Also adds a function, weather_is_slippery(), to determine which weathers should cause slipping.

Feel free to nitpick this, I've got no problems with updating anything.