You can vaguely see the 3M's bar codes installed in these two traffic signs. Business Insider/Danielle Muoio 3M is the company behind well-known inventions like Post-It notes and Scotch tape.

3M is now helping automakers by tucking hidden messages in traffic signs that only self-driving cars can read.

General Motors and Ford are working with 3M to use infrastructure to get autonomous cars on the road faster.

The same company that invented Post-It notes is now helping self-driving cars see the world.

Headquarted in St. Paul, Minnestoa, 3M is behind the creation of everyday objects that everyone uses but no one thinks about. Post-It notes, Scotch tape, and waterproof sandpaper are just a few of 3M's products that have contributed to its $30 billion in annual sales. The company even created the first reflective signs, which are now standard on all roads.

That last point is key because 3M is using its expertise with signs to assist with autonomous car development. The company, which now boasts 90,000 employees, is tucking invisible messages into traffic signs to help self-driving cars figure out where they are.

"There’s not a lot of discussion around how infrastructure is going to help vehicles get to that Level 4 or 5 — and it will be critical," Colin Sultan, the head of 3M's Connected Roads division, said in an interview.

Sultan is referring to fully self-driving cars — ones that don't need a steering wheel because they can handle any driving scenario. Tesla Autopilot is considered a Level 2 system because a driver still needs to take over in most situations.

Automakers like Tesla, General Motors, and Ford are pouring money into an array of sophisticated sensors and cameras that can help cars detect obstacles and locate where they are on a map. Some experts, however, argue that these sensors are not enough.

There's a few reasons for this.

A Ford Fusion equipped with autonomous technology. Ford

One example is that systems like Tesla Autopilot rely on clear lane markings to keep course on a highway. If the paint is faded, the vehicles get confused.

Autonomous cars also need hyper-sensitive GPS systems to avoid objects in their path.

Self-driving cars are equipped with high-definition maps that give them a sense of what a road usually looks like. If it detects an obstacle that isn't usually there, it can maneuver to safely avoid it. But if the GPS is off by even half an inch, it can cause chaos.

"There’s lots of different examples of how automated and connected vehicles may not be ready yet," Sultan said. "How do we all work together to make sure that we can enable those vehicles on the road, but that they have enough safety redundancies?"

Sultan said that's where 3M's tech can help.

The company is installing bar codes in signs that only self-driving cars can read. The codes can relay information like precise GPS coordinates or whether there's a traffic light up ahead.

The self-driving cars may not need it all the time, but the idea is the extra information is there just in case.

3M's biggest trial of the technology is on a three-mile stretch of I-75 in Oakland County, Detroit. The company collaborated with the Michigan Department of Transportation to install its bar codes in work zone signs and construction workers' vest so cars know to slow down and be extra cautious.

Sultan said 3M has trials all around the globe through partnerships with different automakers and tier one suppliers. He said Ford and GM are among the company's partners.

Self-driving cars have a long way to go. But 3M's efforts with the government and major automakers show advancing basic infrastructure will be key to advancing the technology.