Portuguese drivers have a bad reputation. They speed, tailgate, never use the indicators, drive while on the mobile phone, etc.
The roads are not perfect either, and there are a lot of roundabouts.
But don't let any of this put you off to drive in Portugal, most issues are in city traffic, otherwise it is a joy to drive.
And the worst in city driving are mobile phones. Slow traffic? Look around, everyone is on their mobile phone checking Facebook and Instagram or chatting on WhatsApp. Red light? Again, look around, everyone is on their mobile phone. It's forbidden to do so, even with the car stopped. You need to park your car to be able to use your device.
Major quirks of driving in the cities
The main thing is the lack of indicator use. Portuguese drivers need to be psychic and guess when and where another car is turning. By any means, do use your indicators. This is not a case of "When in Rome", as if you don't use your indicators and are on a rental or driving a car with another country license plate, you will hear the horns of other drivers.
The only time they use their indicators is the hazard lights, but mostly to park anywhere in the middle of the road. There has been a recent crackdown by authorities on this type of behavior, but it's still quite common.
Drivers will tailgate you, and yellow lights just mean go faster. In cities is normal to see drivers thru a red light and almost no one stops at a yellow light. If you are near the lights check your mirror for tailgaters and start braking early to warn them you are actually going to stop.
Make sure that there are no cars still passing if your light turns green. Portuguese drivers in the cities tend to go thru red lights quite often
Speed limits are also mostly a suggestion, although the use of speed cameras is on the rise and the average speed as dropped a lot in the recent years. Also there are speed traffic lights. These might be green or flashing yellow and if you go above the speed limit they turn red. A great idea, avoids a ticket and makes you slow down, right? Not really, most of the times if are going 50km/h and will be stuck at the light because another driver flies past you at 80km/h, go thru the green lights and after a second or two will go to red. The speeder keeps going, you get stuck.
Also, on roads with less movement the outside lane of a roundabout is used as parking. Police has been cracking down on this.
Talking about parking, second lane parking is a custom. If you find your properly parked car blocked by a car in front of you just honk your horn loudly and someone will come and remove it. If not, call the police, but most of the times they will do the same, just use their police siren to see if the owner removes the car.
And roundabouts, no one knows how to use them. The rule is to use the outside lane to exit on the next exit, use the inside lanes to go around and gradually merge to the outside lane just before your exit. Be ready to have drivers cut thru two or three lanes of traffic to take an exit. In case of an accident in a roundabout the blame is always on the driver switching lanes, so be aware.
Roads are in bad shape with potholes and missing lane markings.
Zebra crossings are often on junctions, so you have little reaction time to check if someone is crossing. Pedestrians don't really look to see if someone is coming their way, they have the right of way and use it as some sort of divine right.
Cyclists are another issue, they will not respect red lights and zebra crossings and the police will turn a blind eye to such behavior as the fines are very low.
Major quirks of driving in the motorway
Speed! Drivers will be speeding no matter what. It's not as bad as it used to be because fuel is now very expensive and speed cameras are everywhere. But you will find that the average speed on the motorway is 140km/h when the limit is 120km/h.
Tailgaters are another issue, usually younger drivers. They will get really close to you and flash their headlights. Don't be intimidated, when possible change lane and just let them go. But be aware, if there is a lot of space on the lanes at your right, drivers will pass you on the right.
And guess what, slow drivers are another issue. There are obligatory minimum speed limits on the motorway. 90km/h on the left, 70km/h on the middle lane and 50km/h on other right lanes. Going 90km/h on the right lane is already slow, so if you see a slow driver in front try to pass them. If you get stuck behind them you might get in a accident if a speeder is distracted and shunts you from the back.
Major quirks of driving in rural areas
Portuguese countryside is bliss. No one is in a rush to go anywhere, everyone has lots of patience. So don't be surprised to find a car stopped in the middle of the road, or two cars side by side stopped while the drivers are talking with each other. Usually a light tap on the horn is enough to end the chat.
In villages sometimes people stop their cars in the road and it stays there for hours while they are at the local café or visiting their relatives.
Same as in the city, some roads might not have any road markings at all.