No one gets into their car thinking they're going to get into an accident—that, is until they do. Luckily, we now have dash cams, in-car technology that can be helpful to drivers in the event something goes wrong while they're behind the wheel. If you don't have one in your car already, you've probably heard about dash cams on the news when footage from a tense police encounter or from a foreign country like Russia has been featured due to an unusual situation. However, you likely won't encounter meteorites and crashing airplanes as often as you will annoyingly aggressive drivers.

The Consumer Technology Association estimates dash cams will become more mainstream in US cars soon, and dash cam sales rose 9 percent this year (wholesale) and 7 percent in dollars. By 2017, dash cam sales could reach a total of $52 million, possibly even $90 million when combined with rear windshield or backup camera sales.

Dash cams are unlike regular cameras or smartphones, because they're essentially protective devices—you won't necessarily know if the car next to you is equipped with a dash cam, and you're not supposed to. You also may purchase a dash cam and never have to pull footage, and some users won't be able to justify buying a device that they install once and never "use." But the one time you find yourself in a driving predicament, a dash cam can provide invaluable information about a crash or incident you experienced on the road.

With interest and the number of offerings on the rise, we set out to test a couple of dash cams and a few dash cam apps. Here's how they work, what features you shouldn't compromise on, and how the driving experience is changed by having a watchful eye in the car with you.

What to look for in a dash cam

Video quality

Arguably the most important feature of any dash cam is its video quality. Preferably, you'll want a camera that records FHD (1080p) video with its main lens. Some dash cams with dual cameras (one to record the road in front of you and one to record you driving) have lower-quality back-facing cameras, and that's not too bad as long as the video quality is at least HD (720p). Anything below that will produce pixellated images that aren't very useful.

In the same vein, the front-facing camera should have at least a 150-degree field of view (FOV). That will ensure it captures most of the action in front of your car while you're driving. Anything above 150-degrees is a bonus; if positioned correctly, such a camera can capture information at the outermost corners of your windshield's view.

As mentioned before, some dash cams have rear-facing cameras, but others also have rear windshield camera attachments (essentially tiny separate cameras that monitor the activity behind you). In general, these are considered non-essential compared to front windshield dash cams, possibly because in the case of being rear-ended, the person behind you is typically at fault. However, there are plenty of cases where drivers have found rear windshield cameras to be useful for showing the circumstances around accidents and other incidents.

Storage capacity

Most dash cams record and save videos and photos to a microSD card, and the most popular storage capacity is 32GB. Some, like Rexing's V1 dash cam, support up to 128GB, which is ideal for those with long commutes or anyone who spends a lot of time in the car. Storage capacity is a factor to consider for longterm dash cam use, but you should immediately check if the camera you buy comes with a microSD card. When I received the Vantrue N2 for instance, I was surprised to find that it didn't come with a microSD card, leaving me scrambling to get one before I could use it. Most cameras that come with a microSD card give you an 8GB or 16GB card, and that's good enough to get you started. You can always decide if you want to upgrade to a higher-capacity card.

Another feature that goes hand-in-hand with storage capacity is loop recording, or whether the camera automatically records over old footage to maximize memory card space. Most dash cams have this feature, making it so you never have to take the memory card out of the device to delete old footage, though you'll still want a larger card if you want to keep track of longer spans of time.

Audio recording

Most dash cams worth investing in support audio recording inside your car, but it's something you'll want to double-check. Some super cheap dash cams may not support audio recording at all. Conversely, some cameras like the Vantrue N2 have mute buttons so you can turn off audio recording if desired.

Mounting options

While they are an obvious feature, mounting options can be key. Most dash cams come with a suction mount that allows you to stick the camera to your windshield, and I found this was the best way for me to secure our tested dash cams in my car. Others may also offer a dashboard mount, but those can be harder to remove if you want to move the dash cam to another vehicle or change its position in your car.