I find myself behind the wheel of a highly modified Honda Legend (aka the Acura RLX in the States) in the paddock of the high-speed loop at Honda's R&D facility in Tochigi, Japan. This model has been outfitted with a prototype version of the automaker's upcoming highway autonomous driving system and I am about to get a first-hand demonstration.

Piloting the sedan out of the paddock and onto the course -- a high-speed banked oval track meant to simulate an expressway or interstate highway -- I am instructed to press the Auto button on the steering wheel. This causes the dashboard display and head-up display to illuminate blue, signalling me to take my hands off of the wheel and feet off of the pedal. Lights hidden in the steering wheel illuminate to indicate autonomous drive mode's active state, and away we go into the future.

Honda

Autonomous highway drive

The first thing that impressed me about the prototype was how smoothly its system transitioned from my releasing manual control to the autonomous driving mode. There was no jerk in the steering or accelerator, just a smooth surge as the system automatically activated the turn signal, accelerated up to our cruising speed of 100 km/h (about 62 mph) and steered itself into the proper lane.

The autonomous drive concept uses a combination of cameras, LiDAR, GPS and radar to sense its place in the world and the area around it. Small sensors on sides of the rear bumper, for example, watch for cars in adjacent lanes when merging -- though there were none during our test -- and the forward cameras orient the car within the lane. I noted how smoothly the system stayed centered in the lane with none of the bouncing back and forth between the markers like many current lane keeping systems do.

Though, this was a very straight road under very controlled conditions and I'd like to see how Honda's autonomous drive would handle a road with more bends.

Antuan Goodwin/Roadshow

From fast lane to traffic jam

One neat trick is that this prototype system can automatically change lanes to overtake slower moving vehicles. Another Honda vehicle was staged on the course ahead moving at 60 km/h. As we approached it, the autonomous car automatically signaled and steered into the next lane, accelerating back up to our 100 km/h target for the pass.

Things get interesting when there's so much traffic that passing isn't an option. Another Honda vehicle staged ahead moved to below 30 km/h (about 18 mph) and the prototype was instructed not to pass, simulating a stop-and-go slow traffic jam. Because the speeds are so very low during a traffic jam, Honda allows the driver to relax their attention away from road. During the demo, I was able to watch video content on the in-dash display -- something I noticed a number of drivers doing in non-autonomous cars in Tokyo traffic -- and was able to even participate in a Skype call with some Honda representatives.

Antuan Goodwin/Roadshow

Once the blocker car moved aside and our speed increased, the system prompted me to direct my attention back to the road. Despite being autonomous, the car still wants the driver to be attentive, looking ahead and ready to reclaim control in case of emergencies at higher speeds. To make sure that I was looking ahead, a small infrared camera hidden next to the infotainment screen watched my face. If I spend too much time looking down or away, it would have warned me to pay attention.

As we approached the end of the loop, the system automatically signaled for an exit lane change and notified me with audio that it was time to reclaim control. The blue steering wheel lights changed to amber and, when it sensed my hands on the wheel and feet on the pedals, the autonomous indicator lights all powered off and I was free to guide the car back into the paddock.

I was most impressed by the smoothness of the maneuvers, from lane keeping to lane changing and passing. But this was a strong first showing in a very controlled environment; it will be interesting to watch how well it will perform when it has to share the road with human drivers -- drivers who like to squeeze into the safe following-distance left by the traffic jam assist and don't always use their indicators.

What happens when things go wrong?

My demonstration went perfectly with no issues or hiccups, but what happens in the real world when something goes wrong? What happens when some driver activates the system and, for example, has a heart attack or passes out and can't regain control of the car when it's time to exit?

Honda has a four stage system for transitioning control back to the driver in both planned and emergency situations. First, the driver is notified visually and audibly. This is the gentle amber light and nice voice that told me to regain control and exit when I was approaching the paddocks at the end of my test. If I'd ignored or was unable to respond to the gentle alert, stage two is a more urgent alert, like flashing lights and beeping. If I was too distracted to take note of that, stage three is a tactile alert like a vibration in the seat belt. In the event of an emergency, stage three might even include automatic braking.

So far, these are looking a lot like the sorts of warnings that you get with Honda Sensing forward-collision mitigation in current-gen vehicles, and that's enough for most distractions. However, an autonomous car will have a fourth stage for emergency situations where the driver may be disabled: the ability to maneuver the vehicle autonomously to a safe haven, such as the side of the road, activate hazard lights and possibly call for help. Honda's highway autonomy system has yet to demonstrate this but I was assured that it would be able to do such a thing when it hits the road.

Honda's also building redundancies into the hardware to make sure that the car itself doesn't become disabled when operating autonomously. So there are dual power supplies running dual ECUs -- the electronic control unit that powers the tech -- and separate parallel systems that run the automatic braking and autonomous steering. So, if there is a failure in the electronic power steering, the Honda will still be able to at least stop itself safely. And if there's a failure to one of the electronic brains, the car will still have a backup brain alive to notice that something is amiss and instruct the driver to regain control.

Surface roads

In the real world, this would be the sort of system that you'd activate as you enter the highway and disable once it's time to exit back to surface roads. However, the next step beyond exit-to-exit highway autonomy is a car that can drive itself on surface roads. Honda demonstrated this technology as well in a different vehicle outfitted with an array of forward cameras. The vehicle piloted itself around the R&D facility following the road, stopping at stop signs and intersections and making left and right-hand turns.

Antuan Goodwin/Roadshow

The AI behind the cameras is able to detect road lane markers or, if there are no painted lines, the road's edge. The computer is constantly analyzing clues about its environment to make guesses on, for example, where the stopping point for an intersection is or where the center of the road is, even if unmarked. The system can also read street signs for speed limits, stop at stop signs and watch traffic lights. The short demonstration didn't involve any people or traffic, but Honda gave a peek at how they plan on tackling that as well.

The cameras use machine learning to detect and predict the behavior of pedestrians and cars. For example, they detect the direction a human's head is pointing and use that as an indicator of where they're going to walk, since most of us tend to watch where we're going. It even knows when a person is staring at their cellphone and can take greater care. Using that information, the car should know whether or not a pedestrian standing curbside is waiting to cross and if it needs to stop to let them pass or just carefully make its way around them.

The next steps

Honda is planning to have its highway autonomous drive system in vehicles by the year 2020. I was pretty impressed with my demonstration and feel pretty confident that they'll hit that mark. They may not be the first -- other automakers have more aggressive goals and are already inching toward the mark with current vehicles -- but Honda will make it.

The target for surface road autonomy is a more nebulous "sometime after that," with the final frontier of a car that can totally drive itself under nearly any circumstances (Level 4 autonomous) being 2025. Honda has stated that it is testing the waters of a potential partnership with Alphabet's Waymo autonomous driving division. They will work together toward that Level 4 goal, but details are lacking because the companies are still in the courtship phase.