If East is positive and a car is moving East and accelerating West, what is happening to its speed? Velocity?

-- Its speed is decreasing.  If the situation keeps up long enough, the speed will decrease to zero, and then begin to increase again.-- The magnitude of the velocity is decreasing, but its direction remains pointing to the East.  If the situation keeps up long enough, the magnitude of the velocity will decrease to zero, and then immediately begin to increase again with thedirection pointing to the West.