Trips in Yehudah and Shomron

Q: Is it permissible to travel to Yehudah and Shomron, or is it forbidden based on the commandment of "You shall surely safeguard your soul" (Devarim 4:15, 23:11)?
A: It is permissible. There is a clear distinction in halachah between a high-probability danger and a low-probability danger. If this were not the case, we would not be able to travel in a car since every year, to our great distress, six hundred people are killed in car accidents in Israel. Many more people have been killed in car accidents since the establishment of the State of Israel than in all of the terrorist attacks and all of the wars, even when they are added together. We nevertheless travel in cars, obviously with required caution, since this is called "a non-frequent damage" in halachah (Pesachim 8b). In our time there are statistical tools to verify the frequency of a danger. There is a halachic responsum on this subject by Ha-Rav Yitzchak Zilberstein, Rabbi of "Ramat Elchanan" (a neighborhood in Bnei Brak). A student was learning in a yeshiva in "Yesha" (Yehudah, Shomron or Gush Katif) and his parents were concerned about the danger. Ha-Rav Zilberstein proves that "a frequent damage" is five percent. This means that if – G-d forbid – five percent of the students of the yeshiva were murdered, it would be forbidden to learn in that yeshiva. This is obviously far from the reality - Baruch Hashem - since the terrorist attacks in Yehudah and Shomron are not killing five percent of the population. In fact, Ha-Rav Yitzchak Isaac Herzog in Shut Heichal Yitzchak proved, based on Shut Rabbi Akiva Eiger (#60), that a frequent danger is not five percent, but one in a thousand. Baruch Hashem, terrorist attacks in Yehudah and Shomron are not killing one in a thousand people either.

Furthermore, it is permissible to take a "small risk" for the sake of a mitzvah, and traveling throughout Eretz Yisrael is a mitzvah. The Tiferet Yisrael discussed this principle on the Mishnah in Massechet Berachot at the end of chapter one. There is a story about Rabbi Tarfon who said the Shema at night while reclining according to the view of Beit Shammai. He endangered himself while doing so and the Sages admonished him for following the view of Beit Shammai instead of Beit Hillel. But the question remains: Why did Rabbi Tarfon endanger himself, since reciting the Shema is not in the category of "Be killed and do not transgress," i.e. requiring one to sacrifice his life for its fulfillment? The Tiferet Yisrael explains that it was permissible since there was only a small risk of danger. There is an additional proof from when Rabbi Akiva was in jail, and he used the water he received for "netilat yadayim" (ritually washing his hands) instead of for drinking. The halachic authorities ask: How could Rabbi Akiva endanger his life for this practice? The answer is that Rabbi Akiva understood that he would obtain more water. The danger he was taking was extremely minute and it is permissible to take a small risk for a mitzvah. This is also the ruling found in "Pitchei Teshuvah" (Shulchan Aruch, Yoreh De'ah 157).
In conclusion:
a. A non-frequent danger is not considered a danger according to halachah and the danger in Yehuda and Shomron is a non-frequent one.
b. It is permissible to take a minimal risk for a mitzvah and traveling throughout all of Eretz Yisrael is a mitzvah.