if (count = 1)
This is an assignment statement, not an equality test.
You would not want to test for equality, anyway. You want to do something when count > 0, not any specific value greater than 0.
Are count and directionCount volatile?
In order to get good timing data, the time the interrupt occured needs to be recorded in the ISRs. Finally, while didling with the time and count values, you really should disable interrupts, so you are not interrupted during the computations. Re-enable them when done.
And last, but not necessarily least, GET RID OF THE delay()s. You probably want to only calculate and output speed and direction once every few seconds, but don't use delay to make that happen.