In Vayikra 7:11-12 we read "This is the law of the zevach shlamim, peace offering that one will bring to God. If he brings it as a thanksgiving offering."

According to Rashi, One brings the offering regarding a matter of thanksgiving for a miraculous act which occurred to him such as if he returned from a sea voyage, crossed the desert, was healed from an illness or emerged from prison.

Although we don't have sacrifices today, The Gemara in Brachot 54b states that these four categories of people must recite a blessing. What blessing should they recite? Rav Yehudah said: "baruch gomel chasadim tovim", "Blessed are you who bestows beneficial kindness". The Rif, Re'ah, Rambam and Rosh record a different text: "baruch hagomel lechayavim tovot shegmalani kol tov", "Blessed are you who bestows good things upon the guilty, who has bestowed every goodness upon me". We are showing our appreciation for God's bestowing kindness even upon the wicked and for bestowing kindness on us even if we are not deserving of it. The latter is the text that we use for Birkat HaGmel today.

The Gemara in Brachot continues: Abaye said: A person must give thanks in the presence of ten (a minyan).

Birkat HaGomel is traditionally said after the reading of the Torah. One reason why is because in order to have a public Torah reading there must be a minyan. Another reason is that we are publicly acknowledging all of the good that God has done for us.

Today, Birkat HaGomel is said after being saved from any dangerous situation, not just from the four categories listed above. The most common situations where Birkat HaGomel is said are after childbirth, after a car accident and after flying in an airplane. Some say that it is not necessary to say Birkat HaGomel after an airline flight because today driving a car is more dangerous than flying in an airplane.

In Israel today, all elementary school students are required to take a class in Road Safety to insure that the next generation will be educated enough to prevent road accidents which have caused more deaths in Israel than all of the wars put together.