Why does a conducting strip have to touch the ground on a car in hot weather?

Answer 1

The absence of electric conductivity factors throughout the immediate environment, such as air and soil humidity, nearby vegetation, urban electric grid, or nearby constructions, in the middle of desert areas, can cause a situation in which it is very hard for "Static Electricity" to reach ground connection (electric contact with deep soil) therefore a car (and even people) are subjected to accumulate "Static electricity" as if they were batteries, and that can cause malfunction or even damage to electronic instruments and components in the car.

This effect is caused by the positive electrical polarity in the air (+) not been able to find an efficient electrical conductor to drive it to the negative polarity in the soil (-) (Ground Connection). Although, it takes a very particular sum of factors (or lack of them) for this effect to take place (no humidity, no vegetation, not conductive soil, no power grid).

The ground connection strip works as an electrical "path" which static electricity accumulated in the metallic mass of the car will use to make its way to the ground, so the car will not accumulate static electricity.

The tires of the car are not good electrical conductors, that is why you need the strip in order to make direct electrical contact with ground, since it is made from a very good conductive material.

The reason why the strips are not standard equipment in all cars, is because this effect is very rare, and the scenario needed for it to take place is not common in most parts of the world, it is more common in dessert areas in the middle of hot and dry weather conditions.

It is mostly common to operate the car in a relatively conductive environment in which is very hard to find accumulation of static electricity, since the conductive factors in the surrounding environment (high humidity in air and soil, nearby vegetation, power grid) favor the flow of the positive polarity from the atmosphere to the negative polarity of the soil with relative freedom.