False speed report

I am using: vector vel = llGetVel(); float speed = llVecMag(vel); in a car script to determine speed. Once the car has started, it reports motion up to and over 3mps even when the car is not moving in any direction. Can someone explain or tell me how to correct this?

ummmm, no, but I would suggest that you display the vector version as well, so you can see for debugging purposes what direction you are allegedly creeping in.

could be something silly like straight down, and it is the acceleration that gravity is applying to you each frame before the collision with the ground re-zeros your speed - who knows

You could very simply fix it by saying if the speed <3 speed=0, but that's a hack not a nice solution.

It there anything else going on? Something silly like +=llVecMag() rather than just = say?, or when stopped you're not checking llGetVel() so it's reporting it's last speed rather than it's current speed? (This might happen if you're using the controls() to trigger the speed test for example, if there's a slow process in there.

I'm sure something funny is going on. There must be something else in play. In every vehicle whose speed I monitored the speed registers 0.000000 unless it was bobbing (in which case i get a very small value due to z). But not 3. That's avatar walking speed btw.

Its a common 'ghost bug' where, if velocity stop to 0, llGetVel will report a previous velocity from before stopping. I noticed this a while ago, but the script I was writing wasn't picky enough to care much. I blame SL, and Canada.

-Kokiri

If you still can't figure out what the problem is, physics might simply be broken, and it would be better to use llVecMag(oldPos-llGetPos()) as your speed function.