The Project One has been a challenge for Mercedes-AMG.

After more than six years, the company's moon-shot car hasn't hit the streets.

The delay of the cars was not revealed by Mercedes. Although Mercedes brass still refer to it as Project One, the name changed to the Mercedes-AMG ONE. The company made an actual production model on May 31st. The AMG ONE would not be legal to drive on public roads in the U.S. after it got buyers in the US on a video call.

The official notice of the decision not to homologate the car for the US was shared by a Mercedes-Benz spokesman. Meeting US road standards would compromise its performance and overall driving character. We decided to offer the car for road use in Europe, where it complies with applicable regulations.

The company made a single production car, but the spokesman wouldn't say if full, sustained production had begun or not. It was not clear how many cars had been planned for the US and whether any of them would be delivered. Even though it's illegal to drive it as a commuter car, it can still be used as a show car. The spokesman wouldn't give a further comment.

The goal was to adapt the Mercedes F1 team car into something that would meet street safety, sound and emissions requirements. It would need to start with the push of a button and be sturdy enough to navigate the normal dips and bumps of highways and city roads. The lightweight carbon fiber used in F1 is difficult to replace. It had to keep the mind-blowing speed of an F1 racer.

The team worked for years to adapt the race-car engine into a 1.6-liter V6 with direct injection and electric motor, as well as an automated seven-speed transmission, all wheel-drive and multiple drive modes. The rooftop air intake looks like a shark's fin and is one of the most distinctive features of the car.

The 2.27 million (2.41 million) marvel from back in 2016 is still relevant today due to the fact that most of the people who signed up years ago are still on board.

The conversation has been edited to make it clearer.

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The ONE comes with automated seven-speed manual transmission, a 1.6-liter V6 hybrid engine and four electric motors. The door panels are made of high-grade carbon fibre and when shut integrate smoothly into the sporty interior.

There have been no deliveries of the vehicle.

The cars will be delivered in the second half of the 20th century. We will follow the plan.

This has been difficult to produce.

It's true. I asked if we could say that we were drunk when the idea was born. A few guys came together and said, "Why don't we bring a Formula 1 car to a street legal version?"

I was in the room and said okay. I didn't realize that I would be the one who finished it.

It is great that you are talking about the challenge.

It actually is. It took me a while to get used to it. You are kind of embarrassed as an engineer. You don't want them to know. I only get problems the entire day in my position. This is what I want. It's alright with me. He opened my eyes after I spoke to him. I don't want to buy a car that is difficult to develop.

I asked if he knew how complex it was. He said that he understood. I don't think you should apologize because of the delay. Only a customer can say that. This argument was taken from him.

Is it possible to cancel the car entirely?

We said, "Why don't we just stop the project?" Make a race car or give people the money back.

What was the biggest challenge?

There were a lot. The exhaust treatment is the first thing people think of. The Formula 1 car is running at a high rate of speed. The race engineers told the team that they couldn't run at 3000rpm.

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The two-seater’s “Race Start” goes from a standstill to 125mph in just under 7.0 seconds.

Normal driving on the street is not appropriate.

It's right. The exhaust was treated to make it street legal. Looking back, I think the biggest challenge we faced was on the software side.

How do I know?

If Lewis Hamilton sits into his car and wants to start the engine, you can see a group of people standing around the car. A group of people help him start the engine.

It requires a village.

Project ONE allows you to start a car by putting these people into hardware and sensors. There is a whole team sitting in the back office with their computers if Lewis goes on a test run. How he is doing is up to them. This had to be put into software and hardware for the car. That was a lot of work.

It's a nice car now that it's close to being brought to customers.

It has been splashed around a lot as an exciting upcoming thing for a long time.

Project ONE would be the opening picture even if there was a guy talking about tires for anSL. We always make fun of it and say that we use it for something. We were able to understand the future of electric driving thanks to this car.

It isn't an electric car.

It is not possible to say yes. There is an electric motor in it. If you know how to deal with the energy, you can drive this car quickly. You have to make a decision about what kind of vehicle you're going to drive, it's completely different to a regular engine.

Is there a concern that people who put their names down on a list to buy the car will think it's outdated now that it's come out?

It is not possible to say yes. The customers are part of the project and so they have to be talked to. We wouldn't be able to work in that car without these people. They are giving us money and having fun with it. Sometimes it's not so enjoyable.

It was enjoyable.

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Mercedes says it will have a substantial announcement regarding the car in the next few weeks. 

It is enjoyable. That is a great one. We went through a lot of pain, but now the customers want to know what's going on. We are involved in it.

The customers invest both money and emotion.

People are engaging with us. Video talks were had with customers. We explained that there were problems here and there. We had a bearing problem in the engine. The Formula 1 car's bearing was stronger than ours.

What's the reason?

The engine on a Formula 1 car only lasts for a short period of time. The Formula 1 car has more wear on it than this bearing does. That's a cool story if you talk about it to customers. I think that car is nice.

I apologize for being late because it's a German attitude. Other car brands might say "You're getting something special". We are not sorry. It's something that happens in the game. Is it outdated? It is not possible to say yes.

Have you ever had people withdraw their money?

I'm not sure. We have a waiting list, but we may have one or two for other reasons.

There are one more questions. How does the AMG One fit into Mercedes-Benz's plan to grow on the high end and get rid of some low-end stuff? Can we expect any other new cars? It's on top of the GT.

I'm not saying anything. You don't want to think about the next one if you're near the point where we're about to bring the car to the customers. Don't say never, but never say never.

The Mercedes-AMG ONE will be on display for the first time during the Festival of Speed in England.