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  • Kat Allen

Why Autonomous Vehicles Will Need to Be Social Robots

Where I live, outside Boston, Massachusetts, there are a large number of relatively narrow streets, even out well into the suburbs. These streets curve and turn in strange ways, following ancient cow paths avoiding hills that may have long since been flattened down into housing or shopping centers, leading to a large number of strange-angled intersections where one person waiting to turn left might hold up traffic for an entire light cycle.

From this traffic nightmare comes an awkward solution: the "Boston Left".

Rules For a Boston Left:

  • If you are at a four (or more) way intersection controlled by a traffic light, and

  • If there is no left turn lane, and

  • If both directions of travel get a green light at the same time (neither is delayed to allow the other to turn first), and

  • If the first vehicle on the opposing side of an intersection is signaling a left turn OR

  • If the vehicle indicating a turn creeping forward into the intersection as the cross-traffic light cycle ends to indicate that they intend to exercise this option (because some MA drivers seem to believe using turn blinkers is revealing information to the enemy)

Then when the light turns, the first (or possibly first 2-3, if they are quick) vehicles planning to turn will be allowed to go before the (legally prioritized) straight-traveling traffic proceeds.

There are a number of things that can eliminate the driver's permission to pull a Boston Left:

  • Not beginning the turn within the first few seconds after the light changes (especially if the other driver can see you using your phone)

  • Backed up traffic on the cross street, such that the turning driver could not complete the turn without blocking the intersection

  • New York license plates or bumper/window stickers

  • The straight-traveling driver being in a hurry or otherwise not feeling like being generous today

This is difficult even for experienced human drivers. A Boston Left includes a wordless and potentially faceless dominance challenge/evaluation, multifaceted situational analysis, and lightning-quick execution of action--all based (primarily) on the "body language" of a 2000lb hunk of metal and plastic. Out of towners have little hope, and might be best served by parking and riding the T.

But even as bad as a Boston Left situation is for a human who learned to drive in a place where the streets are on a grid and laid out by urban planners instead of bovines, the situation for the current generation of autonomous vehicles is much worse. Autonomous vehicles drive according to the published rules of the road, which sounds like a good thing, but is actually kind of a disaster.

They stop at stop signs and wait for other vehicles to come to a complete stop before proceeding, so they get stuck at the stop sign when human drivers roll through or creep forward . They struggle with merging onto highways and changing lanes because human drivers do not leave the legally required amount of space between vehicles traveling at speed. And they have no ability to process (or execute) the complex dance of creeping forward at a red light to make sure that you're not stuck through another full green when you just need to turn out of this traffic nightmare and onto an empty side street before someone decides to pull forward and block the box again. (At least self-driving cars never block the box?)

So how can we fix this? Autonomous vehicles are going to need to become Social Robots. Social scientists will need to study the social rules of driving - and then teach the autonomous vehicles to follow them. Engineers and system designers will have to decide how aggressive to make their cars, and at what point being a "perfect" by the book driver is actually less safe than bending the rules to follow the custom. (Ever tried staying at exactly the speed limit on a major highway? Definitely not a reliably safe choice, sometimes not even in the rightmost lane!)

Or we could all just start following the rules of the road. What do you think? Will it be easier to teach autonomous vehicles to drive socially, or to teach Boston drivers to follow the rules? Let me know what you think in the comments!

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