It’s 2015, not all car crashes have to happen. (Chieko Hara/Associated Press)

Imagine for a second a world in which no driver ever gets rear-ended. That may sound impossible, but it shouldn’t. For perspective on the blistering rate of technology’s advancements, remember that a few months ago mankind launched a probe from a satellite and it landed on a comet that was traveling at a whopping 84,000 mph.

Today it’s possible and relatively inexpensive for us to make cars and trucks that identify an imminent collision and automatically brake, preventing or lessening the severity of an accident.

Ragunathan Rajkumar, a professor at Carnegie Mellon who is developing self-driving car technology, says that for $700 or $800 the parts can be bought to build such a system. After markups, he estimates that consumers will pay an extra $2,000 or $3,000 for the initial cost of their vehicles. That up-front cost probably would pay off down the line through lower insurance premiums and greater safety.

“We don’t have to wait for a perfectly autonomous car,” said John Capp, director of global vehicle safety at GM. “There’s a lot of great features of driver assistance now that people will really enjoy.”

The impact of these technologies could be huge. Worldwide, 1.24 million people die in car crashes each year. Consider that during the four deadliest wars the United States fought in the 20th century, 39 percent more Americans died in motor vehicles on U.S. roads than on battlefields.

The most common car crash in the United States is a rear-impact crash — 32.9 percent of crashes involve a vehicle plowing into the back bumper of another. Cameras and radar can be used to identify when such a crash is imminent, warn a driver and then automatically brake if the driver fails to. Although these systems aren’t yet mainstream — 27 percent of 2015 model-year vehicles can be purchased with an auto-brake system (and the percent of registered vehicles with these systems is much lower) — real-world research shows their potential.

A 2014 Insurance Institute for Highway Safety study found that Honda Accord drivers with a system that warns of imminent accidents had a 40 percent drop in claims for bodily injury liability. Although these drivers still rear-end people — collision claims dropped only 4 percent — the drop in bodily injury liability suggests that drivers are braking and lessening the severity of these crashes.

“Even when the systems fail to prevent a crash, they are preventing injuries because they’ve slowed the speed of the crash down,” said David Zuby, chief research officer at the Insurance Institute for Highway Safety.

While systems that beep, flash lights, tug a driver’s seat belt or vibrate the seat are useful, automatic-braking systems are even more potent.

Automatic-braking technology became a standard Volvo offering in 2008. It’s designed for the low speeds of someone driving around a city. A 2013 institute study found that Volvo XC60 drivers filed 20 percent fewer accident claims than drivers of other midsize luxury SUVs. Drivers of the Volvo S60 filed 9 percent fewer claims than drivers of other midsize four-door luxury cars.

These technologies aren’t perfect and there are many accidents they aren’t preventing. Automakers have been careful in their implementation of the technology because they are wary of false positives.

“We will miss some scenarios because of this balance between intervening right and not intervening when needed,” said Erik Coelingh, senior technical leader at Volvo. “In this gray zone, we make the decision not to intervene because it’s more important to not disturb the driver and gain acceptance of this type of technology.”

Volvo has set a goal that by 2020, no one should be killed or seriously injured in a Volvo. It has developed a more advanced crash-avoidance system that works at all speeds.

“All indications on the test track indicate it’s working really well, but we don’t have the actual proof based on real world statistics,” Coelingh said.

We can’t really see the full benefits of these technologies until drivers clamor for them, and are comfortable with the higher prices. Zuby says that the take rate on these systems is 5 to 25 percent, depending on the manufacturer.

“It’s not just the customers, it’s also what the dealer thinks his customer wants,” Zuby said. “In the United States, most people go to their local Ford dealership or Volvo dealership and they buy a car off the lot. What I have found in trying to buy cars for our test program, or for my personal use is that a lot of dealers don’t stock cars that have these systems. You have to do some pretty extensive searching to find somebody who’s got that car.”

This also raises another question. If consumers aren’t jumping to buy automatic braking systems, will they ever pay for a self-driving car, which is sure to be even more expensive?

Related: How self-driving cars would benefit Americans more than world peace