How Road Diets Impact Self-Driving Cars

Dr. Lance Eliot, AI Insider

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[Ed. Note: For reader’s interested in Dr. Eliot’s ongoing business analyses about the advent of self-driving cars, see his online Forbes column:]

There must be hundreds or maybe even thousands of different diet regimens that you can opt to use.

Some diets might be good for you, while others can have adverse consequences that outweigh the benefits of the dietary aspects.

Let’s consider another kind of diet, namely a road diet.

If you aren’t familiar with the notion of a road diet, don’t feel too bad about not knowing what it is.

In some sense, road diets are a bit of a fad that seems to come and go.

Generally, a road diet consists of taking an existing roadway and altering it to reduce the number of traffic lanes or otherwise adjusting the nature of the traffic lanes. The roadway is usually still the same overall width. The width of the lanes within the overall width of the roadway are the target of the changes or adjustments.

Besides referring to these kinds of changes as a road diet, there are some that simply call it “lane reductions” (but that’s not very catchy, is it), and others that refer to it as road re-channelization (a hefty 5-dollar word that makes it sound more scientific).

Depiction Of A Typical Road Diet

Allow me to provide you with an indication of what a road diet might consist of.

Suppose that your town or city has a four-lane road that is known as Main Street.

There are two lanes going in the southbound direction and two other lanes going in the northbound direction. Traffic moves along on this handy thoroughfare. Perhaps this Main Street has been in existence for many years and seemed to serve the needs of the town or city quite well over those many years. It has become a heartened part of the tradition and lore of the place.

But, there are some in the community that have qualms about the layout of Main Street.

It is dangerous for bike riders to ride on Main Street, and even when hugging the curb, there have sadly been periodic instances of car accidents involving wayward automobiles striking kids and adults on bikes. Another concern is that the cars driving on Main Street tend to go faster than the speed limit, often acting like they are driving on a four-lane open highway instead of down a busy street with lots of shops and businesses. There have been many circumstances of pedestrians that almost got hit while trying to cross Main Street.

What to do?

Some would say that this Main Street is primed to go on a road diet.

Here’s what we’ll do.

The total width of Main Street is 44 feet.

There are four lanes of 11 feet each.

Let’s get rid of two of those car traffic lanes, which frees up 22 feet. Since we want to help out the bike riders, let’s use 5 feet respectively on either side of Main Street for a devoted bike lane. In the middle of Main Street, we’ll put a new lane that’s 12 feet wide and allows for making left turns.

Overall, here’s what we originally had for the 44-foot wide Main Street:

  • 11-foot southbound car lane
  • 11-foot southbound car lane
  • 11-foot northbound car lane
  • 11-foot northbound car lane

Once we put the roadway onto the devised road diet, it would contain this:

  • 5-foot bike-lane southbound
  • 11-foot car-lane southbound
  • 12-foot car-lane mix for south/north left-turning traffic
  • 11-foot car-lane northbound
  • 5-foot bike-lane northbound

We are still within the original 44 feet of Main Street.

This makes life somewhat easier because if we had wanted to widen Main Street it would have been quite extensive and expensive roadway infrastructure project. We would have had to uproot the sidewalks and the various fire hydrants and light posts. Since we are only changing the lanes within the existing overall width of the road, the effort to make the changes will be a lot less costly and arduous to undertake.

I’m not suggesting that the road diet changes are somehow cost-free or cheap to do.

Having to re-stripe the road and potentially make other modifications to accommodate the new plan can definitively have some substantive costs. If you compare those costs to widening the road or making other more substantive structural changes, on a relative basis the road diet is likely more affordable.

Road Diets Vary

Not all road diets will necessarily stick with the original width of the road.

You can have instances of widening the overall width of the road, even when it is undertaking a so-called diet.

Constricting the car traffic to now just one lane in each direction is likely to slow down the cars.

There are some studies that claim that the proper use of a road diet can reduce car crashes by around 47% and reduce speeding by about 70%.

Those studies also suggest that there might be an increase in bike riders of around 37%. Plus, there might be an increase in pedestrian foot-traffic of around 49%.

Road Diets Not All Rosy

Not all is necessarily so rosy on Main Street, though.

If the drop to just one car traffic lane in each direction does constrict traffic flow, it might lead to heavy congestion now on Main Street.

Cars might be snarled all along Main Street, trying to get to their destinations. This heavy traffic might become visually a blight and might also increase noise or odors. It could frustrate car drivers. People might now find themselves taking much longer to drive to wherever they are trying to go and thus burning up more gasoline and wear-and-tear on their cars.

An unintended reaction by the drivers could be that they decide to spillover into nearby neighborhoods. This self-diverting of traffic could increase the risks for pedestrians and bike riders in the adjacent neighborhoods.

Whereas maybe Main Street is now safer, it could be that the risks and potential car accidents are merely being shifted into those other streets.

Some would argue that another disadvantage of constricting the car traffic involves the potential delaying of first responders to an emergency.

A police car that is trying to quickly get to a crime scene and that uses Main Street might be delayed by the traffic congestion now on Main Street. Likewise, there might be delays to ambulances or fire trucks.

Another possibility of something amiss could be that cars begin to avoid using Main Street whatsoever.

This certainly reduces the volume of traffic and might aid the use of Main Street for the bike riders and pedestrians. But, it could also lead to less people driving to and visiting the shops and businesses that are lined along Main Street. Those shops and businesses might soon discover that their revenues are drying up due to the road diet.

As you can hopefully discern, the road diet is a practice that often involves great controversy.

Controversy And Road Diets

Many cities or towns that start toward using a road diet approach will often do so quietly and without much fanfare.

It kind of slips under the radar of the populace.

Not everyone though is quiet about the adoption of road diets.

One such example of a road diet controversy took place in Santa Monica, California , and I was caught up in the matter as someone that at the time routinely drove through the area in question.

Press coverage encompassed both those in favor of the road diet and those in opposition.

The opposing forces called it a draconian lane reduction, some called it a debacle, some said it was a road diet disaster. There were even efforts to recall some of the politicians that had been involved in the road diet effort.

As you might guess, there was a lot of hand wringing too because some that generally believe in road diets were worried that if this road diet was expunged it might curtail all future road diet initiatives.

Generally, there is much debate on all sides of the road diet approach.

Road Diets And AI Autonomous Cars

What does this have to do with AI self-driving driverless autonomous cars?

At the Cybernetic AI Self-Driving Car Institute, we are developing AI software for self-driving cars. One aspect that is considered an “edge” problem involves the nature of road diets as it relates to AI self-driving cars.

It is considered an edge problem since it is not at the core of what most of the automakers and tech firms are focusing on. They pretty much are focused on the rudiments of getting the AI to drive a self-driving car.

Road Diets As Aiding Autonomous Cars

Returning to the topic of road diets, let’s consider how road diets are related to AI self-driving cars.

First, some pundits argue that we ought to consider implementing road diets as a means to support the advent of AI self-driving cars.

It is assumed that we will gradually have lots and lots of AI self-driving cars on the roadways.

Some believe that we should consider blocking off many downtown areas to reduce the amount of car traffic and increase the amount of foot traffic and biking that can occur.

The use of a road diet approach would presumably aid in this notion.

This seems sound in theory and nearly Utopian.

There will be a long-time overlap of human driven cars and AI self-driving cars.

Would both human driven cars and AI self-driving cars be both allowed into these road dieted locations?

If so, the human driven cars would presumably have a more difficult time coordinating their driving activities than would the only-AI driven cars.

It is likely that these road dieting efforts will encounter many of the same qualms already expressed about today’s road diets.

The impact might be that the road congestion generated becomes untenable. It could be that the traffic delays generated become untenable. And so on.

Trade-off Aspects Of Implementing Road Diets

Some of the disadvantages of road diets can be likely better controlled via the use of AI self-driving cars.

For example, the spillover effect can be potentially reduced by informing the AI systems of self-driving cars that they are not supposed to try and avoid the road diet by taking side streets. This could be possibly pumped to the AI via the on-board OTA (Over-the-Air) electronic communications, which usually involve providing updates or patches to the self-driving car.

In general, the aspects of adjusting downtown areas onto a road diet has both its positives and its negatives.

If you could ban human driven cars from those road dieted areas, it might make for a more orderly use of the available car lanes.

Whether humans will put up with being banned from driving in those areas would seem like an open question and one that might generate a lot of public debate and controversy.

Even if you could ban human drivers from those areas, you still need to consider how much car traffic you are anticipating.

I say that because even if you have only AI self-driving cars allowed into a road dieted location, this does not somehow magically overcome the volume and timing of the car traffic axiomatically. You can only get so much water to flow through a pipe of a certain size.

The other major aspect to consider about AI self-driving cars and road diets consists of the specialized driving nature of traversing and using a road dieted location.

There are some AI developers that say there is nothing unusual or new about driving in a road dieted location. In their book, if an AI self-driving car can navigate a normal road, it should be able to do the same when navigating a road dieted location. I consider this to be a head-in-the-sand belief and one that can bode for problems when AI self-driving cars get themselves into such specialized circumstances.

Specialized AI Driving Capabilities Needed

Road dieted locations do have a specialized element and therefore merit specialized AI capabilities to properly undertake.

As already mentioned, one aspect would be the driving practices of the AI self-driving car.

Another aspect involves whether the road dieted location might have special cut-out areas that are intended for loading and unloading. It is expected that for the safe and efficient delivery of goods and people, there will be various street cut-out areas to allow for loading and unloading, more so than typically is available today. The advent of large volumes of deliveries via AI self-driving cars and ridesharing will increase the need for these specialized zones.

The AI self-driving car needs to be versed in approaching, stopping, and then resuming a car driving journey in these road dieted locations. This must be done with the utmost safety and with the realization that there will likely be a significant presence of both pedestrians and bicyclists.

The AI self-driving car also needs to be ready to cope with the V2V and V2I electronic communications that are likely to be occurring in those road dieted locations, sifting through what might be a voluminous amount of information and coordination aspects.

Another aspect involves the potential for pranking of an AI self-driving car.

It is anticipated that humans might try to “prank” AI self-driving cars, doing so by for example stepping in front of an AI self-driving car to get it to come to a sudden stop. The odds are that this kind of pranking will occur even more so in a road dieted location, due to the higher volume of nearby pedestrians and bike riders. The AI system needs to be versed in dealing with the pranks.

Another potential difficulty for an AI self-driving car would be the encountering of a road dieted location for the first time.

If the AI self-driving car did not realize beforehand there was a road dieted location on its driving journey, perhaps it is not marked as such on a map or GPS, the AI system needs to detect that a road dieted location exists and that the self-driving car has entered into it. Once having discerned and mapped out the road dieted location, it could potentially add this aspect to its repertoire as part of the Machine Learning capabilities.

Road diets, they are coming.

The emergence of AI self-driving cars will likely promote the adoption of lane reductions and road diets.

This should not be done blindly.

A road diet can be a boon to a local area or become a nightmare.

Either way, if a road diet is instituted, the AI of the self-driving car needs to be ready to cope with the particulars of a road dieted location.

It is important to make sure that the AI is beefed-up and not too slim on how to best and safely drive in an area that’s gotten a slenderized road diet.

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Copyright © 2019 Dr. Lance B. Eliot

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Dr. Lance B. Eliot is a renowned global expert on AI, Stanford Fellow at Stanford University, was a professor at USC, headed an AI Lab, top exec at a major VC.

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