Fallout 3 traps

Traps in Fallout 3 can be found all over the Capital Wasteland.

Cars and motorcycles
Though more an obstacle to avoid than a trap, a large number of decaying vehicles can be found around the Capital Wasteland. These nuclear-powered vehicles, suffering from two centuries of neglect, will catch fire and explode if sufficiently damaged (around five hits from a plasma rifle will destroy one outright). When a vehicle takes enough damage, it will release a small explosion and catch fire, giving the player several seconds to escape. Once that period has elapsed, the vehicle goes up in a much larger and more damaging nuclear explosion, similar in appearance and potency to a mini nuke. The explosion can be hastened by firing upon the flaming wreck.

An exploding car can be deadly to anything nearby. Anything standing on or next to the car will more than likely be killed instantly. In addition, the explosion may set off other nearby cars, potentially without any delay if the Damage Threshold is achieved. In areas like parking lots, this can result in up to a dozen simultaneous nuclear explosions.

NPCs and enemies will move away from cars that have caught fire and will eventually explode, but typically do not flee quickly enough unless they were already far enough away from the vehicle. This can be demonstrated by sniping the blue car in the parking lot near Meresti trainyard.

Though cars are not technically traps, they are used as such in Minefield, which the player will likely first visit during the quest Traversing a Mine Field from the first chapter of Wasteland Survival Guide. The sniper Arkansas will deliberately fire on the cars from a distance should the player wander too close to them. Being cars, it is impossible to actually prevent this short of killing Arkansas (who will have likely hit them anyway by the time you get in range) or detonating them yourself. However, you can avoid this by sticking to the buildings and moving in cover.

If you cause a car to detonate, the splash damage counts as damage you inflict on NPCs and can make them hostile against you. If that splash damage kills a target, you do not get XP for the kill.

Mine
Frag mines are a product of RobCo Industries for military use and are commonly laid in areas occupied by hostile forces. They have a very sensitive sensor that registers vibration on the ground, and when the vibration exceeds a certain level, it detonates. Followers will trigger them as easily as the player. The length of the fuse is based on the player's explosives skill; the greater the skill number, the longer the fuse. They require an explosives skill of 1 to disarm, meaning any player can disarm one. They can be picked up after being disarmed. If any enemy or follower steps directly on one there is a chance of them being killed instantly, as the blast could blow their leg(s) off. If the player stands directly on one they will lose a large amount of health depending on the armor they are wearing.

Bear trap
Bear traps are a spring-operated pair of spiked jaws that snap shut on the player's leg should the pressure switch in the middle be triggered. This can cripple the limb at lower levels. A repair skill of 25 is required to disarm them. Shooting the switch or dropping an object on it also works. Bear traps can be reset, but this requires a repair skill of 55.

Swinging object
Swinging objects are simple, heavy objects (often a girder, automotive engine, or rotting brahmin body parts) chained to the ceiling and held up by a trip wire. When the wire is broken, the object swings down and impacts the player for a minor amount of damage. The trip wire requires a repair skill of 25 to disarm, or the object itself can be grabbed and manually moved to a safe "down" position without any required skill (if it's too high to grab, you can usually trigger it from a safe distance by shooting it). Because of the nature of the trap, it can remain dangerous even after the initial trigger. At certain angles, especially if walked into, it will cause damage, often several times in quick succession. It can also cause damage when manually moved by the grab action.

Grenade bouquet
The grenade bouquet is a cluster of three frag grenades hung from the ceiling. When triggered, either by simply walking into it, shooting it, or hitting the nearby trip wire/pressure plate, the pins are pulled and the three grenades will fall to the ground, exploding after a few seconds. Both the tripping mechanism and the grenades themselves can be disarmed, the latter of which requires an explosives skill of 30. Doing the latter adds the three grenades to the player's inventory. If the player lacks the required skill to disarm the trap, they may be able to shoot the rope holding up the grenades to make them fall and detonate safely away from the player. This trap is extremely dangerous, as the combined force of three grenades can be deadly depending on the player's proximity to the blast. They make a tell-tale rattle noise when they fall, alerting players if they fail to notice the trap beforehand, but their vector does not appear on the HUD like thrown grenades.

Trapped pipe
Similar to the grenade bouquet trap, some ventilation pipes have a grenade bouquet installed inside them, the payload of which is primed and deployed by the activation of a nearby pressure plate or tripwire. This trap is uncommon, but can be found in locations such as the ruins of Fairfax, just outside of Madame Jealle's in L'Enfant Plaza, Arlington Library or the steelyard of The Pitt. They cannot be disarmed, though the trip wire or pressure plate can. When activated you will hear the sound of the grenade bouncing through the pipe and dropping onto the floor shortly before exploding.

Pitching machine
Inside buildings, pre-War pitching machines have been set up as weak traps. A nearby pressure plate or trip wire triggers the machine, which fires about ten baseballs before exhausting its supply. Either part can be disarmed. The danger of the machine lies more in the noise it makes, as the baseballs do very little damage. Any nearby enemies will be alerted by the thunking noise it makes when in operation. An excellent example of this trap can be found in the Arlington Library; in addition to the danger of flying baseballs in the choke point, the noise from the trap attracts raiders.

There is also a modification of this trap in the add-on Point Lookout—a pitching machine there shoots 8 baseballs and 2 frag grenades, making it a deadly trap for a character who is already wounded.

Gas leak
Gas leaks are areas which have filled with natural gases that ignite if any sort of combustion occurs within the area of the leak. They are usually found in tunnels and can be visually detected by noting a wavering distortion in the air. When a gas leak is ignited, anything in the immediate vicinity takes a small amount of damage, is set on fire, and is knocked down for a few seconds. This can be particularly dangerous in combat situations if the player is caught in the explosion and the enemy is not. Guns will set off a gas leak if fired within a cloud but not from outside. Energy weapons, such as the laser pistol, will set off the leak if the shot intersects the cloud at any point (this is noted by a user manual for the laser pistol found in the Metro-Central station. Energy weapons from add-ons do not seem to do this). The detonation of any kind of explosive, such as a frag grenade, within the cloud will also set off the leak. Finally, any item with an open flame, such as the flamer, heavy incinerator, or Shishkebab, will ignite the gas if it comes into contact with the cloud, regardless of whether or not they are actually fired, since the pilot light used to ignite them is active. Holstering them will prevent this. To safely remove gas leaks, ignite them from a safe distance (laser pistols are good for this purpose).

Pinkerton uses the gas in combination with the grenade bouquet: by triggering the tripwire, the grenades will drop, and the explosion will ignite the gas. However, unless the player did not kill the mirelurks on the lower level, this is at best a minor inconvenience, as the gas fills the entire hallway and the player will probably have left the range of the grenades.

Radiation trap
Radiation traps are added with the Broken Steel add-on. As the name suggests, they release intense radiation when active. They require a repair skill of 60 to disarm. Only two locations in the game feature them: Holy Light Monastery, where they can only be activated manually; and Olney Powerworks, where they are triggered as a security measure before you ever get near them and must be shut down using a nearby terminal.

Rigged shotgun
The rigged shotgun is a simple but dangerous trap consisting of a combat shotgun wired to a pressure plate or a trip wire. When triggered, it fires a single blast at the position of the trigger. A repair skill of 45 is required to disarm the gun itself. Disarming the gun rewards the player with a combat shotgun, four shotgun shells and 10 microfusion cells (used to power the mechanism which pulls the trigger). Unlike traps such as grenade bouquets, rigged combat shotguns can be disarmed after having been triggered.

Rigged baby carriage
A particularly devious and complicated trap, the rigged baby carriage consists of a perambulator containing a toy baby head with a bomb and several frag mines strapped to it. Upon approaching the carriage, the toy will emit a crying sound (an unfamiliar player will thus approach to investigate) and detonate shortly thereafter with a fair amount of force. This will tend to leave most players wary of baby carriages in the future, despite the rather limited distribution of the trap. It requires an explosives skill of 60 to disarm, and unlike most explosive traps its frag mines cannot be salvaged. Once disarmed, it can be rearmed as a time bomb or a proximity bomb. This trap can also be grabbed and moved to a more useful position before re-arming. The bomb explodes when shot, providing an easy removal for characters with a low explosives skill. This trap can be found in the Meresti service tunnel and Hubris Comics.

Rigged mailbox
Similar to the baby carriage, the rigged mailbox is an ordinary pre-War mailbox rigged to explode if anything ventures too close. If disarmed (with an Explosive skill of 45), the explosive is added to the player's inventory. It can then be rearmed on either a timer or a proximity fuse. All rigged mailboxes have a small metallic antenna poking out of the top of some part of the letter receptacle, which helps in distinguishing them in good lighting conditions. You can find some just to the south of the raid shack. Only small mailboxes in front of houses can be found with this trap, thus such trap is quite rare. Large blue US Post Office boxes cannot be rigged to explode.

Rigged terminal

 * See: Trapped terminal

Another variation of the deadly ordinary objects theme, rigged computer terminals can be found in certain locations. Attempting to use the terminal triggers the trap, causing a slight electrical shock followed by detonation of the main frag grenade inside. It can be recognized by the antenna on the back and the warped rear panel. The trap can be deactivated by defusing the back panel. Disarming the trap will move the grenade into the player's inventory. The terminal can then be rearmed in the same fashion as the previous two examples. An example of this trap can be found in the drainage chamber near Jocko's Pop & Gas Stop (the source of Signal Sierra Victor) or near the entrance to Pinkerton's hideout in Rivet City. Note that the terminal is just a trap and does not actually contain an interface; attempting to use it after it is disarmed only displays a dialog box explaining that it must be rearmed to function, which must be done using the rear panel.

Toilet trap
The toilet trap is a simple electrical trap designed to shock anyone who decides to use the toilet (to drink from, in the player's case), and can be disarmed by standing on the bowl of the toilet and removing the microfusion cells from the tank. Thirty-five microfusion cells are in the tank which provide the charge and are added to the player's inventory if the trap is disarmed. Two wires leading from the tank to the bowl indicate a rigged toilet, and they disappear once the trap is disarmed. One example of this trap is found in the Tenleytown/Friendship station's bathroom nearest the Chevy Chase North exit. A skeleton lying near the bowl serves to warn the player of the danger. Others can be found in the Robot Repair Center, The National Archives, the Museum of Technology, and in the Statesman Hotel.

Trip wire
Trip wires are thin, easily broken wires suspended a few inches off the floor, usually just behind doors so players won't see the posts it is tied to. Opening the door doesn't trigger it. Players with the Light Step perk can walk over them without fear. They require a repair skill of 25 to disarm. The player must interact with the posts to disarm it, as the wire is intangible.

Laser trip wire
Found only in Raven Rock, laser trip wires function by detecting when the beam is interrupted, and respond after a one-second delay with a puff of flammable gas, and a burst of flame to ignite it. The tripwire itself is not a weapons-grade laser beam and will not deal damage nor ignite the gas. The laser tripwire emitter can be disarmed with a repair skill of 85 or a science skill of 67.

Pressure plate
Pressure plates are weight-activated mechanisms set off when it senses pressure from the player stepping on it, thus triggering the associated trap, a common example being a rigged shotgun. Bear traps have built in pressure plates. The Light Step perk will allow players to avoid triggering either variety. Pressure plates require a repair skill of 25 to disarm. The bear trap version can be triggered with a direct gunshot or an object.

Proximity fuse
All mines, including the rigged mailbox and baby carriage, work on a proximity fuse. The Light Step perk will negate ordinary mine fuses but not the fuses of rigged carriages or mailboxes. Thus, the choice comes down to attempting to disarm the explosive before it detonates, simply avoiding it, or to fire directly upon it with a gun or explosive of your own (preferably at a safe distance, of course).

Usage
Rigged equipment such as computer terminals are triggered by any attempt to use them. A separate area on the object must be interacted with to disarm it.

Remote detonator
The Preacher in Seward Square apparently sets off his minefield remotely. Mines can also be detonated remotely by shooting them, as Arkansas in Minefield is scripted to do.

Video
YouTube video about House of Traps in Fallout 3: YouTube Fallout 3 Domino Trap
 * http://www.youtube.com/watch?v=VHo8JJKMmVs
 * http://www.youtube.com/watch?v=epA5n0A8Dfk&feature=related