I tried making my own self-driving car to beat Tesla and it didn’t go well

The Tesla Model 3 has been available with “Full Self Driving” for years now. It’s a feature which allows your Model 3 to steer for you in most situations, stop at red traffic lights automatically and handle lane changes on its own, provided you keep your hands on the wheel and are ready to take over at any point.

The thing is, it’s a £6,800 optional extra. I wanted to see if you could get the same technology for a lot less cash, and that’s when I stumbled upon the Comma – a £1,000 device which can give you similar self-driving capabilities to a Tesla. In theory, at least.

To find out if it works, I set myself the challenge to buy a car and fit it with this device for less than the cost of adding full self-driving to the Tesla Model 3. With the Comma costing £1,000, I had £5,800 to find a suitable car.

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Making my own self-driving car: finding the right car for the job

Finding a car for this challenge wasn’t as simple as just buying an old banger, because it had to meet certain criteria. The most important being that it has to have adaptive cruise control with lane-keeping assist.

I had my eye on a BMW 3 Series and a Jaguar XF. Both were within budget and had the right kit, but then I discovered that the Comma isn’t compatible with those brands. Bugger.

It is compatible with lots of Volkswagen Group models though, so after being messed about by a few people selling Golfs and Audi A3s, I found a 2016 Skoda Superb which ticked all the boxes.

It was the top-spec Laurin and Klement model, meaning it had adaptive cruise control and lane-keeping assist, but it did need a bit of work to get it ready for my test. With almost 170,000 miles on the clock, and seemingly no oil in it, I gave it a service and replaced a few worn brake components to make sure it was safe. Then it was just a case of fitting the Comma.

Making my own self-driving car: fitting the device

Installation wasn’t quite as straightforward as I’d hoped, so I roped producer Nick in to help me out.

The instructions told us to remove the trim around the rear-view mirror and plug an adapter into the car’s front-facing camera, however we found that the wiring just didn’t fit. After Nick did some digging online, we found that it needed to be plugged in under the dashboard. Once we knew that, it was actually quite easy.

We plugged it in and mounted the camera in the centre of the windscreen, then it was just a case of driving around for a bit to calibrate the Comma to the car’s systems and we were off.

Making my own self–driving car: testing it out

The Comma’s software has been tested by over 20,000 people over 300 million miles, which sounds like a lot. However, Tesla’s Full Self Driving feature has been tested by over six million cars and 8.7 billion miles.

So to investigate how both systems perform, I’m going to start on a private track before heading out on the road to test them in real traffic. Things got off to a good start in the Skoda, with it following the road quite well.

That was until we came to a particularly tight corner, because then it did run wide onto the grass. It also got quite confused at the point multiple roads crossed over, and decided to just plow straight across a field.

That’s less than ideal, but the Comma isn’t designed to work on a wide-open runway with no road markings. I tried driving the same route in the Tesla, and for a lot of it the system simply wouldn’t engage. When it did work, the Model 3 did at least come to a stop at the point where two roads cross rather than plowing straight across, which is the safer thing to do.

But the Comma was still impressing me so far. I had only touched the controls once at the point it told me to take over, and when there were clear road markings it was following the road. Time to take it out and test it in the real world.

Making my own self-driving car: the biggest test

To be clear, I had my hands on the wheel at all times when on public roads so I was ready to take over at any point, but for the most part I managed to leave the Comma to do its thing.

Almost immediately it nearly took out one of its alloy wheels on a traffic island. It seemed to like getting very close to kerbs, which was pretty nerve wracking. I also noticed that it wasn’t slowing down for traffic lights or zebra crossings, like the Tesla is supposed to do.

The thing is though, you can work with the Comma. I could steer, brake and accelerate myself without the system disengaging, whereas Tesla’s self-driving feature switches off as soon as you intervene.

And it did deal with a few tricky situations surprisingly well, such as when I met a lorry coming the other way. It slowed down and steered around it no problem at all, and then I realised that it can handle lane changes automatically as well.

When I merged onto the motorway, the Comma worked pretty much the same as the Tesla does. It’ll change lanes when you indicate, and it keeps you a safe distance from the car in front. The problem is, most adaptive cruise control systems will do this as well.

So the Comma is an obvious upgrade over the Skoda’s standard adaptive cruise control system, but it definitely isn’t perfect. It can’t recognise speed limits, give way signs or red lights, and it can’t follow your route either. Once you get to a complex junction, it’ll just go straight ahead.

Making my own self-driving car: how does the Tesla compare?

At this point I decided to jump in the Model 3 to see if it did any better. It is meant to follow your route, and it can use navigation data and sign recognition to react to speed limits.

Interestingly, the Tesla decided to come to a stop at a green traffic light. Only when I tapped the accelerator did it move off again. It’s as if it sees hazards and slows down to warn you of them, and you then have to confirm it’s safe to go before it continues, whereas the Comma assumes it’s safe to go and you have to confirm that it isn’t.

And this is the issue I have with these systems. If I have to be there telling the car that it’s okay to do something, then it renders the whole thing a bit pointless.

I also found that the Tesla, although it was sort of following the right directions at roundabouts, was really erratic in the way it accelerates, brakes and steers. I had to keep taking over.

Making my own self-driving car: have I wasted my money?

I’m going to start by addressing the Tesla. On the motorway, the Model 3’s Full Self Driving is very good, but around town it’s not so useful. You can’t fully rely on it, and despite the name it’s not actually fully autonomous. You still have to be in control, and you’re always on guard watching over it.

And that brings me onto the Comma, because it’s very similar. I was really impressed with what it can do, and it felt well-integrated for an aftermarket add-on, I thought it was a very professional product.

But, like the Tesla, I could never fully rely on it. It’s a little bit like when I’m cooking food for my four-year-old daughter. She wants to join in, and I want to try and let her do a bit of cooking, but I have to keep a really close eye on her and it’s easier to do it myself.

They’re fine on the motorway, but in town they’re just too stressful, which isn’t ideal when you consider the whole point of them is to make things more relaxing.

And then you have to consider the fact that you have to have adaptive cruise control fitted to your car anyway for the Comma to work, and that system is already good enough on the motorway.

The Comma is really impressive, but it doesn’t quite do what you want it to, and neither does the Tesla’s system. At least the Comma, plus the car we fitted it to, came to less than the cost of the Full Self Driving upgrade on the Tesla Model 3. It’s a pretty amazing deal, but it’s not for me.

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