How does the wave of terrorist attacks in Germany affect travelers?

Currently there are no travel restrictions I have heard of.

Politicians are still undecided about what measures to take. For example the mayor of Munich announced that he thinks that more bag controls should be in order and that he considers a ban of backpacks on the Oktoberfest which starts in two months. So as a tourist you should expect that your luggage might get checked more frequently than usual and you should avoid carrying larger bags or backpacks when you visit places with many people.

When there is a political reaction, I would expect that it will rather target immigration policy in general and asylum policy in particular because these are currently in the focus of public attention. Tourism and business travel are unlikely to be affected. But that's just my personal estimation.

Note that statistically speaking, you were still far more likely to die in a traffic accident than from a terrorist attack when you were in Germany in the past weeks.

I am the founder of the website CitySafe which aims to assess the crime and safety levels of large cities and countries worldwide (it’s still work-in-progress, but so far I have done c. 40 cities and countries).

For my answer, I am referring to the page about safety in Germany (including a crime map). (FYI, Citysafe’s rating algorithm has assessed a safety level of 85% (100% being the safest) to Germany, and 78% to Berlin.

While it's true that Germany has recently been targeted by terrorist attacks which resulted in few casualties, they are very rare and do no target tourists. The police presence has been greatly increased in large cities to deter further attacks.

Germany is a very safe country. Crimes rates are very low compared to southern European countries, and law is strictly enforced. It is ranked 14th on the ranking of world’s safest countries.

One thing you should definitely take care of is not to leave bags, suitcases or luggage unattended, especially not at airports and train stations. Not only because it possibly will get stolen but because security authorities are very sensitive to bomb alarms. I saw it twice in the last year that abandoned suitcases caused police action. In one case the area got evacuated and one suitcase was blown up with a jet of water. This happens occasionally in Germany(and most likely everywhere else) and it might get expensive when they find your shorts with your name embroidered afterwards.

There is a detailed and very useful travel advice for several countries by the German Auswärtiges Amt (Ministry of Foreign Affairs). They are up to date and very sensitive towards security. They also provide medical and general advice for travelers in many languages.