Car Tires Don’t Protect You From Being Struck By Lightning
Your Car Is One of the Safest Places To Be In A Lightning Storm, But Not Because of the Rubber Tires.
You may have heard this one before. Some say the safest place to be during a lightning storm is in a car because of the rubber tires because the rubber tires will effectively ground the electrical charge.
An auto IS a safe place to be during a lightning storm, but for a different reason. The tires do little to dispel electricity should the car be struck by a lightning bolt.
To explain why this concept is not true, let’s first clear up three things:
- Lightning is electricity. In the case of an airborne lightning strike,electricity takes all paths available.
- “Metals are good electrical conductors because there are lots of free charges in them.”
- Cars are made of metal.
About 100 yards above the earth’s surface, the lightning bolt’s intense negative charge begins to effect the ground below. Positive charges collect in pointed objects such as pine needles, tree branches and metal poles. Regardless of what object it hits first, a lightning bolt is looking for the shortest path to the ground. If it hits a tree or telephone pole, a lightning bolt could leap sideways out of this object if it finds a better path to the ground nearby. When a car is struck by lightning (directly or indirectly), the bolt will likely first make contact somewhere on the car’s outer frame first. The metal frame conducts this electricity. Since electricity moves so well through this metal and cars are touching the ground, the bolt has little motivation to leave the auto before reaching the ground.
No one can tell where within a car the electricity will pass (wiring, car antenna, outside shell) since electricity takes all paths available. But as long as the passengers are not touching anything metal (such as a door handle, metal steering wheel, or car stereo) at the time of the strike, they should survive the incident. Unless they’re in a soft-top convertible, in which case this scenario doesn’t really apply.
Demonstrated Proof
Raging Planet – Discovery Channel [1]
A 2008 episode of Raging Planet showed an experiment to see what happens when a car is struck by a bolt of lightning. The test was conducted in a high voltage laboratory in the UK. To see if a passenger would be effected by the strike, a dummy was placed inside the car. The dummy was rigged with sensors to detect any electrical currents passing through it. When the car was struck by lightning, the electricity was channeled through the metal frame of the car, around the passenger, and down to the ground through the tires. The dummy inside was untouched. This study concluded that a human passenger would have survived this demonstration.
Top Gear
Top Gear took it one step further. This video (linked below) shows a similar test, but this demonstration replaced the dummy with the show’s host.
Do Tires Play A Role At All?
I was unable to find a good answer for this question since no reliable source definitively said ‘yes’ or ‘no’ and back it up with good evidence.
However, WeatherImagery.com offered this perspective:
By the time a lightning bolt reaches your car, it has been traveling for miles and miles through the air which is many orders of magnitude more resistant than a few inches of rubber. So if the lightning bolt can overcome the resistance of air, it can easily overcome the resistance of a rubber tire.
The Tesla Museum (in Italy I believe) conducts live a experiment by which a person is placed in a metal cage and hoisted aloft. The cage is then “showered” with lightning, showing the same effect listed in your article. The person in the cage is unaffected by the discharge.
Written by Huey on April 8th, 2008Interesting. Do they place spectators in the cage? If that is the case, it must be truly safe to have the metal cage channel the electricity around the person.
Written by Ted Goas on April 8th, 2008