There is an expression in the tremping (Israeli hitchhiking) world, שעות הרחמים (The Hours Of Mercy). It refers to the hours just before the onset of Shabbath, when it is generally considered not a good idea to set out on a journey, lest one should get stuck in some town unexpectedly, or worse, in the middle of nowhere, and then "poof," it's Shabbath.
Yet, Jews set out a couple hours before Shabbath anyway. We do not do this intentionally. I have only done this if I am traveling to the next town or two. Even though Shabbath has been coming in later and later, I will sometimes glance at the clock on Erev Shabbath, and wonder where the time has gone. I have a shower, assuming I won't make it to the miqweh when I get to where I'm going, dress in my Shabbath clothes, throw a few essentials into a shopping bag, and then it's out the door!
Generally speaking, we also have contingency plans. Boys can crash at a yeshiva, if they get stuck along the way. From Elon Moreh and Shavei Shomron in the north, to Jerusalem, all the way down to Susya, south of Hevron, there are many yeshivoth in Yehudah and Shomron (Judea and Samaria). Likewise, girls know where the girls' schools are along the way. Teen-aged men and women from Yehudah and Shomron, generally seasoned trempistim, after their first couple of years of high school, have a networking system all their own. They can also call their parents for suggestions of who they know in particular towns where they've gotten stuck, so that they can show up to their houses as a "surprise Shabbath guest."
If I am on my way to Jerusalem, for example, I happen to know people in Eli, Shiloh, and Ofra where I could theoretically crash, if it didn't look like I was going to make it to my intended destination. If I am still stuck at Tapu'ah Junction, I can always just walk back up the hill, and spend Shabbath at home.
For some reason, though, there always seem to be tremps. Once, on my way to Shiloh, I got a ride from someone from Beth El, an hour and half before sheqi'ah (sunset). Another time, I received a ride to Eli with about the same time to spare.
The reason this time period shortly before Shabbath is called "The Hours Of Mercy" is actually two-fold. I have reports of tremps appearing out of nowhere, as well as drivers stopping for trempistim when they, themselves are in a hurry, and may not even have any room. They find a way to make room, knowing the urgency of the situation, whether the trempist was acting irresponsibly or not.
I have heard various stories of Jews who have not been so fortunate. One man who was waiting for a tremp in front of a town in the Shomron. He realized he was not going to make it to his destination. So he started walkin up the hill to the town, stowed away his muqtze (items forbidden on Shabbath) at the guarding booth, and found a family to take him in after tefillath aravith (evening prayer).
There is also the story of a certain, fellow blogger, who shall remain nameless, who just showed up in Yitzhar one Erev Shabbath. Sounds kind of hutzpadik [AND intentional], huh? Well, apparently not everyone in Yitzhar thought so, as this fellow blogger claimed he had a great time there.
So, yet another reason why the hours just before Shabbath are known as "The Hours Of Mercy," to those of us who travel the roads by the hesed (kindness) of strangers is the mercy shown by the Jews who open up their homes to their fellow, unexpectedly "stuck" Jews, perhaps doubling the power of their misswah of Hakhnasath Orhim (the taking in of guests).
Photos taken from my bedroom window in K'far Tapu'ah, NOT on Shabbath.
Don't forget to check out my comprehensive guide to Tremping.