What Is Automotive Night Vision?

How passive and active night visions systems light up the road

passive automotive night vision

Robert Basic / Flickr / CC BY 2.0

The catch-all term automotive night vision refers to a number of loosely related technologies that can help increase situational awareness when low light conditions make it difficult to see the road.

These systems use thermographic cameras, infrared lights, and heads up displays to extend the perception of the driver beyond the limited reach of headlights. By alerting drivers to otherwise invisible hazards, automotive night vision can help prevent accidents.

What Is Automotive Night Vision for Cars?

Passive Night Vision
  • Uses thermographic cameras to detect thermal radiation.

  • Great for revealing vehicles, animals, people, and other "thermal" objects.

Active Night Vision
  • Uses infrared light to illuminate darkness.

  • Reveals objects that are much farther away than headlights can see.

There are two categories of automotive night vision: passive and active. Passive systems use thermal cameras that illuminate the heat radiating off objects, animals, and people. Active systems use infrared light sources to illuminate darkness.

Both active and passive night vision systems rely on the infrared light spectrum that is invisible to the naked eye. They each have their own benefits and drawbacks.

Passive Night Vision Pros and Cons

What We Like
  • Good at revealing people, animals, and other vehicles.

  • Higher visible range than active night vision.

What We Don't Like
  • Not very good at revealing inanimate objects like rocks or barriers.

  • Less effective in warm weather.

Passive night vision systems rely on thermographic cameras to detect thermal radiation. Since thermographic cameras can "see" heat, it is easy for them to pick out the difference between a warm object, like a person, and a cooler object like a road.

Data from the thermal cameras used in passive systems is processed into a black and white image that provides the driver with an enhanced view of the road. Due to the reliance on heat emissions, passive systems tend to work very well with people, animals, and other vehicles, since they all emit a lot of thermal radiation. The drawback of passive systems is that they have trouble picking up inanimate objects that are roughly the same temperature as the surrounding environment.

The range of passive night vision tends to be higher than the range of active night vision. This is due to the limited power of the light sources used by active systems. However, the image quality produced by the thermographic cameras tends to be poor when compared to active systems. They also don’t work as well in warm weather since an increase in the ambient temperature will naturally cause normally cool objects, like road surfaces, to warm up during the day and then radiate heat after the sun goes down.

Active Night Vision Pros and Cons

What We Like
  • Image quality generally better than passive night vision.

  • Can illuminate objects that are farther away than headlights can reach.

What We Don't Like
  • Does not work well in poor weather conditions, like snow and hail.

Active systems are more complex than passive systems because they use infrared light sources. Since the infrared band falls outside the visible spectrum, these light sources don’t cause oncoming drivers to suffer from temporary night blindness like high beam headlights often do. This allows the infrared lights to illuminate objects that are much farther away than headlights are able to reach.

Since infrared light isn’t visible to the human eye, active night vision systems use special cameras to relay the extra visual data. Some systems use pulsed infrared lights, and others use a constant light source. These systems don’t work very well in adverse weather conditions, like heavy snow or hail, as it can partially block the infrared light source. However, active systems can provide high contrast images of vehicles, animals, and even inanimate objects.

How Does Infrared or Thermographic Information Help You See?

There are different ways for night vision displays to relay infrared or thermographic information to the driver. The earliest night vision systems used heads up displays, which projected warnings and alerts on the windshield within the driver’s field of vision. Other systems use an LCD mounted on the dash, instrument cluster, or head unit.

Which Vehicles Have Night Vision Systems?

Automotive night vision systems have been around since 1988, but they are still found primarily in luxury vehicles. The technology is usually optional and can be quite expensive. The first night vision systems were introduced by GM, but a number of other automakers now have their own versions of the technology.

Mercedes, Toyota, and Toyota’s Lexus badge all offer active systems. Other automakers, including Audi, BMW, and Honda, offer passive options. General Motor's Cadillac badge also offered a passive night vision system, but the option was discontinued in 2004. There are also a number of aftermarket systems available.

Final Verdict: Does Night Vision Help Reduce Accidents?

According to the European Commission for the Automobile Industry, nearly 50 percent of all accidents occur at night. Since the same study showed about 60 percent less traffic at night, it’s clear that a disproportionate number of accidents occur between dusk and dawn.

Since night vision isn’t widely available, there is no conclusive data to say definitively whether or not night vision systems actually help. A study performed by the National Highway Transportation Safety Administration revealed some people are willing to drive faster at night with the aid of these systems, which could lead to more accidents.

However, other technologies that increase nighttime visibility have been shown to reduce accidents. Since technologies like adaptive headlights have helped reduce nighttime accidents, it’s possible that wider adoption of night vision could have similar effects.

Night vision systems can detect objects that are more than 500 feet away, but traditional headlights typically only illuminate objects that are about 180 feet away. Since the stopping distance of a car can easily be longer than 180 feet, it’s clear that the proper use of a night vision system can help an alert driver avoid collisions.