[Pottus]

You didn't do your homework at all this function is incorrect but you can easily find the correct function on the forums.

Code:

Float:GetPlayerSpeed(playerid)
{
    new Float:px, Float:py, Float:pz;
    GetVehicleVelocity(GetPlayerVehicleID(playerid), px, py, pz);
    return floatsqroot(floatpower(floatabs(px), 2.0) + floatpower(floatabs(py), 2.0) + floatpower(floatabs(pz), 2.0)) * 100;
}

You are also wasting player textdraws and doing extra work when a lot of them should just be global textdraws.

Code:

public OnPlayerDisconnect(playerid, reason)
{
    speedohide(playerid);
    return 1;
}

This does nothing at all.