GCN Mushroom Bridge

Mushroom Bridge is a racecourse from the Mario Kart series. Its first appearance is in Mario Kart: Double Dash!! as the first racecourse of the Flower Cup. Later, the course makes a reappearance in Mario Kart DS as a retro racecourse of the Leaf Cup. The course takes place on a one-way highway near the coast, and the racers have to share the track with slower vehicles that almost always damage the player when struck. The highway that runs over the Mushroom Bridge that gives the course its name.

GameCube
The track starts out just before the first left-hand curve. Players can take a path leading off of the main course to the right shortly after the starting line, which goes down a slope to a Warp Pipe leading to the only Double Item Box found in the course as it blasts the players back onto the track. The course then heads into a curving tunnel lit up with blue lights. The players catch up to the cars they share the track with in the tunnel, and after clearing the curve, they encounter three item boxes.

After leaving the tunnel, the track curves between the coast and some hills topped with mushroom-like huts. A path leads over the hill, but if the players do not have a speed-boosting Mushroom or Invincibility Star, their kart will be slowed down substantially by the dirt. Another alternate route exists in this section of track: there is a sidewalk on the left hand side of the track, and while its usually separated from the road by fencing, there are open sections granting the players access. There are item blocks on the sidewalks, and the fence protects players from projectiles thrown by the other racers, such as Red Shells; they can also avoid the traffic on the main road using this route.

After curving past the hills, there is a short straightaway; the sidewalk empties back into the road, and the racers all pass through a row of three item blocks before entering the second tunnel of the track. The tunnel curves around to the left, opening up on a straightaway leading to the bridge that gives the course its name. Halfway along the bridge are three more item blocks. There are two more item blocks on the tops of the bridge's beams, which are also inlaid with Dash Panels, meaning players who attempt to cross the bridge that way run the risk of losing control and falling off (either onto the track below, which wastes time, or into the water which means they need to be rescued by Lakitu, which takes even longer). After the bridge is the finish line and the start of the next lap.

DS
In Mario Kart DS, the course underwent considerable changes. It is simpler, shorter and doesn't have as many obstacles as in Mario Kart: Double Dash!! All the alternate ways were removed, excluding the shortcut over the hills. This version of Mushroom Bridge now features vehicles from Shroom Ridge. It is also one of the shortest tracks. Missions 5-5 and 7-Boss take place here. In 5-5, the player needs to finish one lap in the opposite direction within the time limit, and in 7-Boss, the player needs to reach the finish before Wiggler.

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Mushroom Bridge returns in Mario & Sonic at the Sochi 2014 Olympic Winter Games as the setting for the Groove Pipe Snowboard Dream Event as the game's equivalent to Mario Circuit as in the Dream Ski Cross event from Mario & Sonic at the Olympic Winter Games. Like the aforementioned event, the entire road is covered in snow and the course is mostly downhill with Warp Pipes and a cannon to take racers to the top of each island. Wiggler Buses can be seen on roads that are inaccessible to the players and a single Wiggler Bus stationary on the bridge serves as a small ramp for the racers. Unlike in Mario Kart: Double Dash!! and Mario Kart DS, the course now has a NSMB-esque aesthetic.

Like in the games it's based off, it is possible to ride up the bridge's beams which is still inlaid with Boost Pads, if done successfully without falling off a ramp will take them to Warp Pipes faster than if the lower route was taken, these Pipes still lead to the same destination as the Pipes below. Throughout the track there are also grind rails which can either lead to alternate pathways or help to boost the player's speed.

Other vehicles
In addition to a hazardous Wiggler Bus, a mushroom-dispensing Mushroom Car and an explosive Bob-omb Car, there are various vehicles travelling through the course with the racers.
 * There are two buses; one says "Star Travel" and has "STR" on its license plate, the other says "Peach Beach" and says "SUN" on its license plate.
 * There are three factory trucks; one says "Moo Moo Farm" and has "1UP" on its license plate; the other says "Express" and has a P-Wing, a Yoshi Cookie, and a letter under it and "SMB3" on its license plate; the last one says "Super Chocolate" and has an 8-bit Koopa Troopa and two 8-bit Goombas on the sides, two 8-bit Marios on its back, and "W1-1" on its license plate.
 * The factory truck that says "Express" is called the Parakarry Mail Truck and is an homage to Parakarry, one of Mario's sidekicks in Paper Mario.
 * Regular red, blue, and yellow cars that have "POW" on their license plate.

Official descriptions
Mario Kart: Double Dash!!
 * Instruction booklet: “One of the Mushroom Kingdom’s most famous landmarks. This bridge is well traveled, so be careful not to run into any commuters. The car carrying all the mushrooms looks strangely inviting, though…”
 * US website: “There’s more than just other karts on Mushroom Bridge – a lot more. Dodge traffic as you race across the bridge, or just go over it!”
 * European website: “This race takes place on a real road, so watch out for the kart-crushin cars. Skilled players can even drive across the bridge’s girders.”

Mario Kart DS
 * European website: "You'll have to contend with rush hour traffic as well as your rivals on Mushroom Bridge and its surrounding streets. Dodge the buses and cars and keep and eye out for a shortcut on the right-hand side, but keep a Mushroom handy because you're gonna need it."

Trivia

 * The whirlpools below the bridge are a sort of reference of the whirlpools that commonly appear in Japanese seas.
 * The music that plays while racing is the same as the music that plays during racing on Mushroom City.
 * In Mario Kart Wii, there is a smaller, similar bridge like Mushroom Bridge in the course Moonview Highway.
 * In the GameCube version, the first tunnel is lit green and the second tunnel is lit red. However, in the DS version, both tunnels are lit green on the left side and lit red on the right side.
 * The track has almost the same shape as Mario Circuit 1.
 * While riding on the top of the arches of the bridge, it is impossible to get hit by Spiny Shells.
 * Mushroom City and Princess Peach's Castle can be seen in the background near the entrance of the pipe. They were removed in the DS version.