The Gemara in Masechet Pesachim (Daf 2) writes that one should embark on a trip specifically during daylight, and should arrive at his destination or seek lodging while it is still daylight, rather than travel at night. Numerous different explanations have been offered for this Halacha. Some commentaries explain that one should travel specifically during the daytime hours so he can avoid ditches and various obstacles along the road. Rashi writes that thieves and vicious animals roam the roads at night, making nighttime travel dangerous, whereas Tosefot explain that the Mazikin (spiritual "demons") threaten nocturnal travelers.
Would this Halacha apply nowadays, when roads and highways are lit with streetlamps, traffic lights, and other means of illumination?
The She'arim Ha'metzuyanim Be'halacha writes that the advent of electric lighting negates the various factors that prompted the Gemara's admonition against nighttime travel, and therefore one may, indeed, travel at night. Nevertheless, one should exercise additional caution when traveling in the dark.
The Kaf Ha'chayim (Rabbi Chayim Palachi, Rabbi of Izmir, Turkey, 19th century), in chapter 110, documents several different laws and customs relevant to traveling. First, he notes that when the Gemara advises that one travel specifically by day, it writes that a person should leave and find lodging "Be'Ki Tov." The Gemara refers to light as "Ki Tov" (literally, "that it is good"), based on the verse in Bereishit (1:4), "Va'yar Elokim Et Ha'or Ki Tov" ("God saw that the light is good"). The Kaf Ha'chayim writes that since the Gemara advises traveling during a period described as "Ki Tov," it is preferable to travel on Tuesday, because during the third day of creation G-d twice declared that this day's creation "is good." Only Tuesday earned this double declaration of "Ki Tov," and therefore Tuesday is the most auspicious day for traveling. By the same token, Monday, on which G-d did not declare, "Ki Tov" at all, is the least preferable day for travel.
It should be noted that the Kaf Ha'chayim does not speak here in terms of strict Halacha, nor does he warn of misfortune, Heaven forbid, if one travels on Monday. He is simply advising as to the most and least preferable days for travel. A person with a flexible travel schedule is advised to plan his trips for Tuesday and avoid traveling on Monday, but this should not be mistaken for an absolute requirement to travel on Tuesdays and to avoid traveling on Mondays.
The Kaf Ha'chayim further writes that one should donate some money to charity before embarking on a trip. He also records a custom to recite before traveling the verses, "Bet Yaakov Lechu Ve'nelecha Be'or Hashem; Ki Chol Ha'amim Yelechu Ish B'Shem Elokav, Va'anachnu Be'Shem Hashem Elokenu Le'olam Va'ed." Furthermore, the Kaf Ha'chayim writes that one should take some money with him on his trip and make a vow that he will donate it to charity upon his safe arrival at his destination in memory of Rabbi Meir Ba'al Ha'ness.
Finally, the Kaf Ha'chayim cites the Sefer Chasidim as admonishing against polishing one's shoes on the day he travels. No reason is given for this Halacha, and it is altogether unclear as to whether the Sefer Chasidim's admonitions are binding. Nevertheless, when possible, one should endeavor to polish his shoes before he travels or wait until he arrives at his destination to polish his shoes.