Transponders

I don't know the answer to your question, but in looking for information, I found this article. It doesn't appear that you need a transponder on the new toll roads, but rather you buy a prepaid ticket. There are two different systems in place, and you need to know the difference, too.

http://www.thebarefootnomad.com/travel-tips/the-ultimate-guide-to-toll-roads-in-portugal/

It's been my experience in Spain, though, that there are equally good roads that do not require tolls. Viamichelin.com shows Madrid to Evora at just over 5.5 hours, but the tolls are only 5.90 euros. In Portugal, your route shows total tolls of 26.85 euros if you always use toll roads. I suppose you have your reasons, but I'm a little curious why you are renting in Madrid if most of your itinerary is in Portugal. If you drove straight from Evora to Porto, Viamichelin shows it as just over 6 hours. That means you are driving almost as far to get to Portugal as you are driving in Portugal - and then driving back. You won't want or need your car in Madrid, so I would suggest dropping it before spending your days there.

Nancy, originally we were flying into & out of Lisbon but all the flights out of Lisbon would require us leave for the airport from 2 - 4 a.m. After calling Delta, I found a flight out of Madrid at a decent hour, dropped the flight to Lisbon on the inbound & saved $300 per ticket by changing the airline tickets to fly into and out of Madrid. This allowed an early arrival for a full first day & leaving around noon allows us a calm exit. By cutting the flight from Madrid to Lisbon we also saved on the cost of the rental car since it was going to more than double if we rented it in Lisbon & returned it to Madrid. Hope that is not too confusing.

Other reasons we like to drive are: I enjoy driving and the freedom it gives us to stop along the way. I research places between cities we are staying where we can stop and have lunch or visit an important or interesting site. For example, in May we toured Rhine Valley, Munich, Salzburg, Vienna, Budapest, Prague, Berlin & Frankfurt. If you look at a map & get ideas from the great people on this website you can find some real gems between these cities as you drive down the road. A couple of examples: On the drive from Vienna to Budapest we chose to stop in Bratislava for lunch which was a great stop. Then as we drove from Budapest to Prague we stopped in Telc for one of our best lunches and an almost empty town square. I have already found several great places to stop on the way from Porto to Madrid. Now we just have to decide which ones are for us.

We are equal opportunity travelers. We believe everyone should travel by their preferred choice of trains, buses, planes, ships or even cars. At different times we have done all of these. Happy travels and thanks Nancy for your help!

Are you still driving in Portugal? If so, this info might be of some help. We were in Portugal in September. When we picked up our rental car (Sixt) we were advised to pay extra for the transponder. We were told that without it on highways without toll booths we would have to pay the toll at a post office and the transponder would save us time and effort. We were happy we did. Some highways in Portugal just have signs and apparently cameras that record your car. There are no toll booths and we did not see any place to pay when we left the highway. Our car had a GPS and when we passed by the overhead toll sign the GPS (or something in the car) beeped. Don't recall an ending beep. Of course, the transponders also charged on those highways with toll booths as we went through the appropriate lane and didn't have to stop to pay. The charges went to the rental car and after we returned the car they appeared on our credit card. Though the transponder was fairly pricey (18Euro) we were happy that we didn't have to spend time searching for an open post office to pay the individual tolls and thought it was worth the extra cost.