Question: We were invited to friends out of town for Shabbos, though our hosts told us that we weren’t allowed to travel on Friday afternoon. Is that right?
Answer: Rambam (Shabbos 30:11) writes that one mustn’t travel more than 3 parsa (approximately 7.5 miles) on Friday as their hosts (or own family) may not have had enough time to prepare for them. The Shulchan Aruch (OC 249:1) writes that if one is expected and no further preparations are needed, however, then they may travel further.
The Shulchan Aruch Harav (OC 249:3) and R’ Ovadia Yosef (Yabia Omer 2 OC 14:6) write that this limit applies to one walking. One travelling by other means has as long as it takes to walk this distance, or 3 hours and 36 minutes (See Shulchan Aruch OC 459:2).The Mishna Berura (249:3) writes that while many aren’t as concerned about this halacha nowadays, we need to ensure not to arrive too close to Shabbos. Likewise, R’ Yehoshua Neuwirth (Shemiras Shabbos Kehilchasa 42:24) writes that as travelling late in the afternoon may lead to chilul Shabbos, one should plan to arrive in good time before Shabbos and prepare for any eventuality.