From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Serpentine Road (蛇 の 道, Hebi no Michi; FUNimation "Snake Way"; Literally meaning "Serpent of Road") is a one million kilometer long (621,371 miles) narrow, winding path located in the Yama Realm – above Hell – which is the only method (other than teleporting) to travel from Yama Castle to North Kaio's World.
Dragon Ball Z
Due to its length, it took Son Goku 172 days to reach North Kaio's World (due to North Kaio saying that the Saiyans would arrive in 88 days, and it took them eleven months total). If one were to fall off the Serpentine Road, they would pass through a thin layer of clouds (it is revealed early on that the clouds are actually edible and quite tasty) and fall into Hell. In the anime, it is also the home of Princess Snake, a filler character who falls in love with Goku and tries to stop him.
- Dragon Ball Z: Harukanaru Densetsu
- In Dragon Ball Z: The Legacy of Goku, you have to cross Snake Way twice as Goku did in the anime. The edges of the road will sap energy (even if the code for invincibility is entered).
- In Dragon Ball Z: Buu's Fury, the game will start at Snake Way after the recaps are done. Unlike Legacy of Goku, it won't take long to get to end, and the edges aren't dangerous.
- In Dragon Ball Z: Infinite World, at the Story mode's Saiyan Saga, there is a challenge for Goku in which he has an established time limit to reach King Kai's through Snake Way. If he falls, he will lose some time but will be replaced on the floor. At a certain point, there is a hidden Dragon Ball beneath Snake Way.
Travelers of the Serpentine Road
- Great King Yemma
- North Kaio (Presumably)
- Son Goku
- Piccolo Junior
- Ginyu Special Corps (Excluding Ginyu) (Presumably, though North Kaio may have simply had them teleported there instead.)
- Raditz (Dragon Ball Z: Harukanaru Densetsu]] (supposedly had a relationship with Princess Snake).
- Contrary to what is stated in the original manga, the Ocean Group dub version of the anime states that Snake Way is 10,000 miles long, contradicting the fact that Goku swam half way around the world in only one day when he was 15 (that would mean that he swam over 20,000 miles in that amount of time). The FUNimation dub gives Snake Way's original length. In Dragon Ball Z Kai, Snake Way is stated to be 1,000,000 miles long.
- To travel a million kilometers in 172 days would mean that Goku was traveling at an average speed of 242 kilometers per hour, or 150 miles per hour, on his way to King Kai's planet.
- In the manga, there is no official time stated that it took Goku to get back to Earth after being wished back during the battle with the Saiyans, but King Kai estimated it would take two days. Going by the two days that was estimated by King Kai, that is 20,833 kilometers (12,945 miles) per hour for a million kilometer trip in 48 hours, which is about Mach 17 (seventeen times the speed of sound) .
- Despite being said that only King Yemma (and then Goku) have crossed Snake Way, in the Other World Tournament saga it was shown that King Kai actually had many people train with him. At that time, however, they may have not actually traveled to his planet and could have trained with him elsewhere such as on the Grand Kai's planet. This was, however, anime filler.
- Snake Way is nearly identical in appearence to Princess Snake in her Giant form.
- In Dragon Ball Z: Infinite World, Snake Way is incredibly short compared to both the anime and manga. Also, Princess Snake's Palace is missing and there are platforms for the player to jump on, although it is risky to jump across them.