Why the Driverless Car isn't coming to a road near you anytime soon

Smart cars can do a lot of things, but they can’t replace drivers just yet and it's not the fault of the self-driving car.

I have a pretty smart car. It can read the speed limit. It can do a reverse park without my hands on the wheel. It beeps at me to tell me to look out for obstacles in my way and to guide me when I’m parking and it screams its head off if it thinks I’m about to reverse if another car is anywhere nearby. It even keeps an eye out to make sure I don’t nod off and drift out of my lane by giving the steering wheel a big shudder if I go over the white line or try to change lanes without indicating.

Great, you might think. All these cool features mean that we must be pretty close to a future of driverless cars in which I can kick back and relax when I’m in my car in the same way I can in a bus or train. But you’d be wrong.

And the reason I know it’s wrong is precisely because my car does have these features.

Smart cars are computers, but computers can get things wrong

My car can read the speed limit, but it doesn’t always get things right. Sometimes an eight becomes a three. Sometimes it reads the speed of an exit lane as sixty kilometres when we’re still on the expressway doing 110 and not exiting at all.

Another thing the car does is read the alert signs that tell you a change in speed limit is coming soon as if the speed has already changed. So, for the car a ‘sixty ahead’ is a sixty NOW. It also doesn’t understand variable speed zones like those outside schools which, where I live in Australia, change depending on the time of day. Nor does it understand the signs on the back of school buses that tell you to slow to 40 kilometres when the bus is stopped in case kids are crossing the road. When I’m behind a bus, the car reads the speed sign as 40 kilometres whether the bus is stopped or happily speeding along.

Fine, you might think. Early days and easy tweaks. These are things that can be worked out.

But in a future of self-driving cars, more important than the occasional misreadings, will be the signs that just aren’t there. For example, if I’m in a shopping centre where the speed is limited to 10 kilometres, and I pull back out onto the highway the car will continue to tell me that the speed limit is 10 kilometres until I get far enough down the road and meet another speed sign. That can sometimes be five or ten minutes or so.

It’s okay for signs to be missing when there’s a human behind the steering wheel. I can make the cognitive adjustment that tells me the highway speed will be faster than the speed in the shopping centre car park, but the car can’t. Can you imagine the kind of anger and confusion that would be caused by a car tootling along the highway at the slowest speed possible while other cars build up behind?

Now I know that by this point some of you are busting to tell me that in newer cars speed signs aren’t just ‘read’ by the car, but are also linked via the navigation system.

I discovered this when I hired a car and travelled across country not long after a series of floods had resulted in lots of wash-a-ways. This meant the trip was punctuated by what felt like constant roadworks. The car did not ‘read’ the slow speed signs at all, but guided by invisible satellites, happily told me I could travel at normal highway speeds.

Self-driving cars and parking

Parking is another issue. 95% of the time my smart car is fine and all the beeps and whistles help, but it’s the crucial 5% that matters. For example, I was pulling into a space in a busy car-park that was overhung by a large willow tree when the car brought me to an abrupt halt half in and half out of the space. It had read the trailing whip of willow that hung down over the park as a fixed obstacle. The car wouldn’t let me move forward and with a honking trail of people behind me I eventually had to give up the place, reverse, and move off.

Once my partner used the automatic park mode to do a reverse park into a tight spot. I don’t like to use this feature because I find it kind of creepy to have the car steering wheel moving without me in control. The car parked fine, and we went off to do out thing. It was only when we returned that we discovered the problem. The place where we parked was in a cobbled street and the car had somehow managed to wedge its back wheel between two stones of the gutter. This meant we couldn’t move forward to get out of the car spot and spent about ten minutes trying to free it by going backwards and forwards by inches.

Now I’m not going to claim that a human wouldn’t have made the same mistake, but usually a human parking at an uneven gutter will compensate by parking a little out from the curb.

Driverless cars on country roads.

The main reason I wouldn’t want to trust myself to a driverless car anytime soon is because of what happens when I drive on country roads. The car is designed to read lane markings and to keep drivers from going off the edge of the road or veering out of their lane into oncoming traffic. All that is fine if you’re driving on a road that has those kind of road markings. When there’re not there, the car gets confused.

There are lots of roads near where I live that don’t have lane markings, or only in selected places. Or they’ll mark the edge of the road, but won’t have a line marking the middle of the road. Or they’ll suddenly pop up a few hundred metres of centre lane for a tight bend. This means that if I’m driving on a narrow country road and I move over to the side because a car is coming in the other direction, my car thinks I’m drifting out of my lane and tries to shunt me back into the middle of the road, and towards the other car – not the happiest of situations. Similarly, if I swerve suddenly to avoid a pot hole, the car will over-correct me back in that same direction.

It's not the car’s fault that it gets it wrong. It’s doing exactly what it’s designed to do. And in the perfect inner-city street, in the perfect city with plentiful speed signs and exact line markings it works fine. But not everyone lives like that. So, while the car may be ready, the roads are not. And it will take a long time and a lot of money to make then ready.

So, if you live outside a certain type of big city, don’t hold your breath on a self-driving car coming to a road near you anytime soon.