The car was stopped between the busy junctions five and six at Westerwood around 4.20pm on Saturday (April 24) and when police spoke to the 30-year-old driver, he was found to be under the influence at the wheel - not through drink but by cannabis - and was charged in regard to this.
However the matter did not end there.
For police decided to search the vehicle and duly found more than a kilo worth of the drug which has an estimated street value of £6000.
Now both the driver and his 19-year-old passenger have been charged with possession of drugs with intent to supply. Police confirmed however that the passenger will face an additional charge - after he was found to be in possession of an offensive weapon.
Communities inspector Neil MacLeod said: "This vehicle stop highlights the commitment of police to tackling the criminal use of our local road networks.
"A number of criminal offences have been detected as a result of a proactive stop of a vehicle driving at speed. Any inference that a driver is under the influence of controlled drugs will result in that driver being subject of a roadside test in the same way a driver suspected to be under the influence of alcohol would be.”