Fallout 3 vehicles

Derelict vehicles are abandoned nuclear-powered automobiles littering the roads of the Capital Wasteland in Fallout 3. Most cars look like a cross between 1958 Ford Edsels and the Ford Nucleon concept car, but there are many variations. Two hundred years of neglect has left their defunct nuclear reactors highly volatile and prone to violently exploding if damaged. Once a vehicle catches fire, an explosion is inevitable, but more damage will hasten it. Their explosion is as spectacular as a Fat Man explosion, but not quite as damaging. The explosion will also make the area - around 3 meters near the car - radioactive for a few seconds.

There are a variety of derelict vehicles dotting the roadways; most are large sedan-sized cars, though there are smaller, one person cars. Heavy semi-truck tractors also can be seen, and take slightly more damage to detonate, but create an explosion identical to other cars. Buses are also encountered, and their explosions are particularly large and devastating, more than twice the size of an explosion created by two cars. Smaller vehicles like motorcycles and street cleaner machines can be shot and blown up, but they do not produce a mushroom cloud explosion, in fact, their "explosion" is extremely small and short, even smaller than a frag grenade/mine explosion.. It can be assumed that motorcycles and street cleaner machines are not nuclear powered because of this and the fact that they do not create radiation after exploding.

Derelict vehicles can either be a hazard or a tactical option in combat. If an enemy is positioned near a derelict vehicle, shooting the vehicle can set it off, dealing massive damage to the enemy. Likewise, it is strongly discouraged to use a vehicle as cover from enemy fire. If you are near a vehicle and you see it catch fire, get away from it as quickly as you can before it explodes. Killing an enemy by exploding a vehicle will not get you a finger or an ear for the Lawbringer and Contract Killer perks.

Often, vehicles in close proximity will set each other off in a chain reaction. One Fallout 3 level designer intentionally created a precisely spaced line of cars on a roadway north of Paradise Falls for the express purpose of blowing up to watch the chain reaction. The high probability of accidentally starting a chain reaction makes getting into a gunfight in some locations, like the Collapsed Car Tunnel, very risky.

There are some derelict vehicles that will not explode no matter how much weapons fire is poured into them. One can discern these from the more dangerous variety by examining the trunk; if the hatch is missing and one can see an empty basin in the back, the reactor is no longer present. The reactor is usually shaped vaguely like the nuclear reactor in the DeLorean time machine in the movie "Back To The Future".

Trivia

 * While interesting and cool to see, the mushroom cloud that comes from the explosion of the car is unrealistic. In the real world, mushroom clouds are not a direct result from a nuclear explosion, but one of enormous size. Basically, any explosion big enough will create a mushroom cloud.

Here's a Youtube video of vehicles exploding shortly north of Paradise Falls:

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