Car night vision, now that it can reliably detect and alert you to pedestrians, cyclists and deer beyond the reach of your headlamps, is well worth considering when you’re looking to buy your next car. The newest and best systems employ algorithms that determine whether an infrared hot spot is a living, moving thing near the roadway, then swivels a headlamp element to alert the driver — and the person or animal.

This is a far cry from the first limited-functionality systems of 2000 to 2014 that cost up to $3,000 and required the driver to continually shift eye focus from the road to the display to the road. Component prices have dropped markedly since then, but you still can’t find an integrated night vision system for under $2,000. That’s now. Systems might ultimately drop below $1,000, and then to as little as $500 for a pared-down units.

The Audi night vision sensor, hiding behind the grille

Night vision systems use an infrared sensor typically in the grille to look for warm objects in the roadway. The sensor is a video camera that captures the infrared spectrum just above visible light. The sensor outputs the moving image to a dashboard display. Increasingly, that’s coupled with sophisticated algorithms that detect humans and large animals, and most recently, that sound an alert. This is the case for all night vision technologies.

The majority are passive night vision systems. Think of passive meaning efficient, not weak or submissive. They measure the heat generated by living objects without the need for additional illumination. Warmer objects show up as lighter images on the car’s LCD, colder objects show up as dark. In between dark grays are the road and rocks emitting heat from the sun into the evening hours. It’s a bit like looking at a photographic negative (see the image at the top of the story). Passive night vision is one of the technologies (along with light amplification goggles and scopes) that excited a generation of Americans watching Gulf War surgical air- and missile-strikes in glowing green hues on CNN. (Less exciting it you were on the ground at the time.)

Passive night vision wins hands down for claimed range, up to 1,000 feet or 300 meters. (At 60 mph on a country road, that’s theoretically more than 10 seconds of travel time.) Passive systems work better in rainy and foggy conditions. The majority of cars use passive sensors, including Audi and BMW. On the downside, passive systems work less effectively at warmer temperatures. They sense polar bears against snow better than camels against sand. BMW for instance says the upper range for effectiveness is 98F (35C). They’re also mounted low in the grille or under the bumper, so much so that when you pull up to a traffic light, you’re almost looking up to the level of the exhaust system on the car ahead. Lugers would appreciate the view.