Pokémon FireRed and LeafGreen/Route 16

'Also known as "Cycling Road," Routes #16, #17, and #18 are a favorite hangout for bicyclists and motorcyclists alike. It just so happens that many of these two-wheeling enthusiasts are Pokémon trainers as well, and you must fight your way down the long slope to Fuchsia City. Once there, you will have a chance to visit the Safari Zone.'

Route 16
Before you head past the guard post, dig your Cut-trained Pokémon out of the computer in Celadon City and use him to snip away at the tree blocking the norther part of Route #16. It's here that you'll find the patch of wild grass that is your first chance to catch a, as well as a secret house containing HM 02, Fly. Use this to teleport to any city you've visited, or for a two-turn Flying-type attack that is similar to Dig.

Route 17
Route #17's brutal slope drags you downward unless you hold the or  buttons to steady yourself. But there's no reason not to speed to the bottom, since the only thing of interest here is the in Yellow.

Route 18
When you get to Route #18, don't miss the trader in the top floor of the guardpost. He'll trade you a Lickitung for a Slowbro. Just before you arrive at Fuchsia City via Route #18, you will find three bird keepers waiting for you on the other side of the guard house. With the help of one little electric Pokémon (you know the one), you can make short work of all three in no time.