drug driving saliva tests may not be accurate, page-9

the only reason i figured there would be a limit is because of the time factor... the saliva test will indicate drug use for the last 2 to 3 hours.... so getting high 2 or more hours before you drive is not going to affect you as much as getting high 15 minutes before you drive due to the high wearing off yeah? there must be a level of impairment that deems you too stoned to drive? plus what if you just have a drag on someone's joint and then drive, you would give a reading but you may not even feel the effects of the weed, there would have to be a limit, imo