In Pokémon Black and White, Route 4 is a huge half-constructed road through a desert north of Castelia City. There are exits at the north and south. It starts off with a paved road which ends abruptly after fifty steps. Along the paved road are a number of large, half-done construction sites. To the west of the paved road by Castelia City's exit there is a large plot of deep sand and a cliff next to the ocean, with two Fishermen fishing there. To the north of the cliff-lined sea there is an another half-done construction site. In the middle of the route, there are two paved roads; one that goes north towards Nimbasa City, and the other facing west and eventually north, leading to the Desert Resort. Over the path to Nimbasa City, just north of the incomplete intersection, there is an overhead freeway going east and west. Trucks can be seen passing over the freeway at high speeds.
Two years later, the road connecting Nimbasa City and Castelia City has changed substantially, and differs dramatically depending on the version that is played. In Black 2 the construction of a settlement along the road has been completed, along with the road having been completed. In White 2, the construction was abandoned after ancient ruins were discovered and excavated.
In both Black 2 and White 2, in the house at the most easternW2 or westernB2 part of the street, there is an NPC who will heal the player's party.
The route cannot be fully traversed until the player has defeated Burgh. In Black and White, a Worker halfway along the paved road will turn the player back if the player does not have the badge from Castelia Gym. In Black 2 and White 2, several Crustle block the route halfway along the paved road; after the player has obtained three Badges, Colress will appear in front of the Crustle; after losing a battle against the player, he will operate his machine on the Crustle to make them disperse.
From male Ace Trainer in a house near Lady Lina if he is shown a Pokémon with an Attack stat equal to (gives five) or higher (gives one) than what he requests. Can be repeated daily, with request values changing every time.
From female Ace Trainer in the southernmost building on the right if she is shown a Pokémon with a Speed stat equal to (gives five) or higher (gives one) than what she requests. Can be repeated daily, with request values changing every time.
Trainer Tips Pokémon have a source of energy for using moves. It's called PP, meaning Power Points. They have PP for each move. When a move has no PP remaining, that Pokémon cannot use that move. That's a good time to head for the Pokémon Center!
Other parts of the route were shown when Ash and his friends left Nimbasa Town and set foot for Nimbasa City. This part was shown to be quite rocky, also having a large mountain home to large groups of Beartic.