Let me make this a little clear here.
1. Any vehicle that can be entered into without using a KEY is considered "Open" and cannot be used to consume liquor or have sex ! (threewheelers, bikes, back portion of lorries etc)
2. Any vehicle that needs a KEY to enter is a closed space and private property... which can be used to Drink, smoke, fuck and sleep .. (cars, vans etc)
3. You cannot drink and drive... but you can DRINK inside a car.. regardless of whether you are in the driving seat or passenger seat.
4. You can SMOKE anywhere you want except for places that are CLOSED with less than 30 seats (if its' an eatery) ... yes.. you can smoke on the road, on the bridge and infront of the police station
5. You CAN DRINK on the road... but you cannot be hindrance to the general public in way of lewd behavior physically, visually or Auditory. BASICALLY You can drink any amount you want and you are free to mind your own fucking business without being an asshole to others.
6. Public places are defined as Government buildings, hospitals, places of worship, schools.
clear enough?