Braking on a vintage road bike I recently bought a vintage Gitane road bike. I understand that in the 70s and 80s they sold a lot of these road bikes with drop handle bars. Sometimes they came with the extra lever for an easier grip from the top but mine doesn't.

Most modern road bikes seem to have more of a grip from the hood which allows you to squeeze the brakes when sitting upright.

So I am wondering if you are supposed to quickly change to the bottom grip to reach the handle bars? Is that something you get used to doing quickly after some time?
Riding in the city seems very uncomfortable having your hands on the brake at all times while looking out for cars.
Is that intended to be used more in touring than in busy city traffic?
It is true that the old style brake levers were not as powerful from the hoods as modern ones. The reason is geometry. 

The picture below shows how old and new levers move when pulled. With old levers, braking from the hoods requires one to pull back and push down at the same time. As said in comments to other answers, this is doable but not very effective or intuitive. With new levers one simply pulls the lever towards one's hand. The small blue arrows show how brake cable moves.



If you want to improve braking on the bike and don't require complete authenticity, there are aftermarket levers with modern pivot placement.