Do You Have to Stop Twice at a Stop Sign?
No, most often stopping behind another car at a stop sign does not count as your legal stop.
According to Section 186 of the Motor Vehicle Act, you must bring your vehicle to a complete stop at a specific location—the stop line, crosswalk, or intersection edge—regardless of whether you already stopped behind another vehicle.

Question: Is it legal to have a nitrous oxide system hooked up to a vehicle in British Columbia? If the bottle is detached from the system, is it legal? Does a DOT/WHMIS oxidizer symbol grant any right to transport it?
The short answer is no, you cannot safely or legally drive on public roads in British Columbia while your arm is immobilized in a temporary sling.