Wednesday, July 5, 2017

The Hitchhikers Guide to Driverless Vehicles

INTRODUCTION -


I start with a caveat; this technology is 5-10years from having a substantial impact on transportation in general, and sustainability in particular. This paper will argue that even in this extended time frame it’s a subject that should receive attention from the sustainable transportation community. Because the technology that supports autonomous vehicles has the potential to have a profound impact on how we move goods and people throughout the developed world its not too early to start considering how to take advantage of opportunities the technology may present as well as anticipate possible negative outcomes. The paper includes an overview of the present state of affairs, an assessment of potential impacts on sustainability, and a historical perspective on changes in transportation and what they suggest about the road ahead.


The endless twenty years
Before enrolling in our program I had an interview with Professor Scott Rutherford. When I asked for his take on the subject of driverless cars he pointed out that when he entered the field, in the 1970’s, it was said driverless cars, or some system like it, was only twenty years away. We can assume that that was true in the 90’s as well. It is now forty years later and it seems that driverless cars are, you guessed it, about twenty years away.


More accurately, a system based on autonomous vehicles is twenty years away. Driverless cars are here, now. The  the relative simplicity of creating a self driving vehicle has always obscured the enormous difficulty of creating a driverless system. That involves creating, perfecting, and then expanding, the role of autonomous technologies in the context of our present human driver based system. Even now, in spite of the relative technical maturity of autonomous systems, there remains a great deal of uncertainty about when, or even if, such systems will become widespread in the real world.


Recent Developments


The Darpa Challenge
What really brought driverless technology to wider attention was a series of DARPA (Defense Advanced Research Projects Agency) challenges that began in 2004. Held in the Mojave desert, challenge vehicles were given a digital map with waypoints that had to be crossed on the way to the finish line, but no further input would be allowed once the vehicle began its run. The first challenge resulted in no finishers. The real surprise came one year later when the second challenge resulted in 22 out of 23 of the teams going further than the most successful vehicle of the previous year, and five vehicles completing the entire route. The third and final challenge (2007) was held in a mock-up of a suburban environment with vehicles required not only to navigate but do so while obeying traffic laws as well. Here too the level of functionality was impressive.


Automotive Manufacturers Investment
The success of the Darpa challenges accelerated interest in several sectors of the automobile industry. The largest investments presently being made are through automotive and component manufacturers. Some companies, such as BMW, Audi (Volkswagen), GM, and Continental (tire company) are attempting to create the entirely autonomous vehicles. At this point, however, the lion's share of investment is being used to develop technology that is related to, or a limited version of,  autonomous vehicles. All the moving parts of a fully autonomous system-- software, computer hardware, sensors, vehicle to vehicle communications--are being developed to support safety features, adaptive cruise control, and navigation/information systems. The amount being spent on related R&D is estimated to be upwards of ten billion dollars annually.


“.....a car can drive itself today. There’s no technological problem with that,” Dr.Klaus Draeger head of supply and purchasing at BMW.


Google
The most surprising new element in the development of autonomous vehicles has been Google’s entry into the field.  The company has already logged over 200,000 miles of autonomous vehicle miles on public roads. Their program is headed by Sebastian Thrun, a prominent robotics researcher that headed up Stanford’s successful Darpa challenge program.


Other demonstrations of autonomous navigation include this driverless Audi TT climbing  Pikes Peak at a (relatively) high speed.  Universities in Germany and England have also successfully tested autonomous technology on public roads.


Legislation
Even more impressive has been the speed at which several states have been establishing legislation to allow the testing of autonomous vehicles on public roads. To date seven states, including Arizona, California, Florida, Hawaii, Nevada, New Jersey, and Oklahoma have enacted or are debating laws governing the operation of autonomous vehicles on public roads. Nevada is furthest along with a license plate design already established for driverless vehicles
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Other governmental agencies are involved with issues directly concerned with the operation of an integrated system. NHTSA is currently testing V2V (vehicle to vehicle) communication systems and considering requiring the technology on all new cars.


Autonomous vehicle technology at this point equals or exceeds human abilities in most respects. Its fundamental attribute, the ability to process, transmit, and act on sensory and electronic inputs, is thousands of times faster than any human driver, and is improving at a relentless pace. makes it a safer option in almost all conditions. Safety and efficiency is increased to the extent autonomous systems are isolated from human inputs. The result is that most of the risk inherent to driverless cars derives from the unfamiliarity and unpredictable reactions of manned vehicles to their presence. At this point there appears to be few insurmountable technical obstacles to the development of the technology. Political resistance as well seems to be minimal. Legal issues are still uncertain, but historical experience suggests that few technologies face insurmountable challenges if they are at least marginally profitable and reasonably safe.


Potentials-Driverless Cars and Sustainability


If autonomous vehicles began to operate tomorrow, why should anyone interested in sustainable transportation be concerned with them? Especially if, as popular imagination suggests, driverless cars will simply allow the latte sipping businessperson to work on their laptop during the morning commute (and have a beer on the ride home)?
There are other possible advantages. The first is fairly simple-sustainability issues (such as safety) that may be the direct result of the vehicles themselves. The second category is speculation about the impact of a system of autonomous vehicles on sustainability issues. The potential of such a system requires more explanation, and more speculation, about how the economy, society, and government will respond to and make use of autonomous technology. But such a system would create a unprecedented increases in personal mobility over time. Unprecedented because it would be able to do what the present system is almost entirely incapable of, regular increases in systemic efficiency.


The question is, of course, how much attention should we give driverless technology. On the one hand there is the time frame issue,  twenty years is a long time,  coupled with uncertainty. On the other, benefits are hard to establish, largely for the same reason. But the last twenty years of innovation, especially in the field of information technology, has given us an idea of what industry and academia is capable of when focussing on technical field. What follows is more likely a restrained picture of the benefits that are possible if sustainability is a central focus in the development of driverless technology.


Direct Benefits
The most exciting direct benefit, from a sustainability point of view, must be the potential for a transit system of previously unimaginably flexibility, reliability, and level of service.


Safety
57% of all car accidents are entirely due to human error, in over 90% it is a contributing factor. Only 2.5% are attributable solely to mechanical error. The human cost of our automobile based system worldwide is over one million every year, 50,000 in the United States. The wounded number at least ten times that. The number of saved lives in the U.S. alone would be in the tens of thousands. The effects of drunk driving, distracted driving, and inexperienced (young) drivers would all be minimized. Pedestrians and bicyclists would benefit from the greater situational awareness of driverless systems.
Congestion
For reasons similar to safety aspects, vehicles under control of a computer are capable of reduced following distances, accident avoidance, rapid rerouting, and other characteristics that increase average traffic throughput and reduce congestion.
Access
Fully autonomous vehicles should allow whole sections of the population--elderly, disabled, youth--access to personal mobility. Without other mitigating factors this increased access may result in increased congestion.


Indirect Benefits/Potentials
Environmental
The relative efficiency of a autonomous vehicle based transportation system is the foundation for mitigation of the present mode’s enormous impact on the environment.  Simply put there is a fully attainable potential of moving ten times as much traffic on one tenth the land area now given over to roads, parking, and right of ways as required by the present system. However,the opportunity of returning large swathes of the urban and suburban landscape to permeable ground cover will only be realized by motivated and organized communities.
A transformation of ownership patterns is almost as important as relative efficiency in driving positive environmental outcomes. The bottom line is that electric vehicles will be more common, and more quickly adopted, when the vehicles themselves are capable of accessing recharging or battery swap facilities. Faster depreciation/retirement of intensively used “shared” vehicles will result in significantly faster implementation of new technology.
Roads will require much smaller right of ways both in height and width. In less developed area this may result in a footprint substantially smaller than even railroad tracks with less structure required to maintain grade. The result should both be aesthetically more pleasing as well as less damaging to wildlife. Coupled with greater sensor range and reaction times (as well as electric drive) it could dramatically reduce wildlife mortality and overall environmental impact.


Freight/Economy
The elimination of labor, the most expensive component of short haul truck transport, will allow disaggregation of loads into smaller units at a substantial remove from each item’s final destination.  Improved flexibility of distribution will allow practices common to just in time manufacturing to be introduced into the retail space. Additionally, widespread use of delivery services become an economical option for the same basic reason. In fact, the prospect of removing labor costs leads to dramatic changes in business models throughout the freight sector.
Even more interesting in the long term is the opportunity to close the loop on production-distribution-consumption cycles. Used products and packaging can be returned directly to producers or designated third parties for recycling, repurposing, or remanufacturing. Governments may require that products be designed with their entire life-cycle in mind.


Capacity Case Study
I’m including this section from an earlier final project to illustrate the capacity of a functional driverless system. What is described is a mature technology, but not the theoretical limit of what can be achieved under controlled conditions.
The proposal focuses on two of Seattle’s most heavily utilized east-west arterials (one of them is part of the focus of Jeffery Linn’s project) It reserves the center (turn) lane of 45th and 50th streets for intermittent use by automated traffic. Special signalling will alert traffic ( and pedestrians) to vacate the center lane (and complete left turns) well in advance of automated traffic. Traffic at intersections along the route would be stopped in all directions and in a sequence allowing uninterrupted passage of vehicles at a steady speed of @ 30 mph along a route stretching from the UW to Ballard neighborhood in the west. The lane would be reserved for automated traffic for 45 seconds (including a 10 second warning period) every five minutes. Vehicles would travel in groups of three tightly spaced vehicles with three vehicle lengths between groups. Aggregation and disaggregation of vehicle groups would take place opportunistically as there would be no physical barrier between traditional and automated lanes. The lanes themselves, especially at intersections, would be heavily invested with sensors and the capacity to communicate directly with vehicles.


Calculation Summary
Assumptions:
  • 35 second passing times with 10 second warning period
  • Automated traffic on 5 minute intervals
  • 3 vehicle platoons, minimal spacing inside platoons (@15”)
  • Average Speed 30 mph
  • Platoon Spacing 3 vehicle lengths


Calculations:
  • platoon length = platoon(ave car length x 3) + spacing(ave car length x 3)= 90ft (@15’ car length)
  • Distance covered at 30 mph = @45’/sec = ½ platoon/sec = 1.5 vehicles/sec
  • Total Number of vehicles in transit during available transit period at 80% efficiency = 35sec x 1.5 vehicles/sec x .8 = @54 vehicle capacity per transit period
  • Total hourly capacity of Lane = 12 transit periods x 45 vehicles= 648 per hour (lane in use 15% of available time)
  • 30 mph Automated Lane 24 hr capacity = 15,500 (one way)
  • Actual 45th street traffic (one way)=11,000  (max @ 900/hour)
  • 55 mph Automated lane hourly load capacity = 6,400
  • Typical Freeway lane,  hourly load  capacity= @1,200
  • 55 mph Automated lane 24 hr capacity  (uninterrupted)= 153,000
  • Actual I-5 one way 24 hr traffic= 150,000


It’s a startling result. A single lane of automated one-way traffic on an arterial such as 45th street, operating for less than two minute intervals every five minutes, could carry the twice the load of one way traffic on that arterial at peak usage. Extending the model to an interstate and making service uninterrupted, a single automated lane (at 80% capacity) can carry the equivalent of five lanes of traffic, almost the entire freeway.
The potential capacity of a driverless system is what usually fires the excitement of someone who wrestles with the glaring inefficiencies of the modern  car based transportation system. Much of the time this excitement leads people to look at designing fully engineered infrastructure, things like PRT’s. While it's fun to imagine the creation of a world tailored to our transportation needs, history suggests a different path of change. The widespread use of driverless cars would suggest a fundamental shift in our society and culture, and changes that big must be driven by more than an engineered ideal. That is not to say that such an ideal will not someday be reached. The reliability and efficiency of many systems, such as high speed rail or the aviation industry in general, could hardly have been contemplated by even the most enthusiastic visionaries of the 19th century. But the process of change is inevitably unpredictable
It is hard to appreciate how quickly things sometimes change. From my office I overlook the ship canal bridge, an important component of I-5 as it passes through Seattle. Over 50 years old, the bridge carries vehicles whose basic design is older still. A driver from 1930 could more quickly learn to operate a modern car than he or she could learn to use a cellphone. The sheer scale of this structure, and the massive transportation system of which it is a small part,  seems utterly resistant to significant modification of any kind. This is the story of the last half century. Can we really expect the next 50 years to be that much different?
However, changes on this scale do happen. History give us some idea of the dynamics driving that change. It also gives us examples of the forces that impede change for long periods of time, and then drive it forward at such speed when change finally does take place.


Transformations- Historical Case Studies


The prospect of the world’s largest transportation infrastructure undergoing a fundamental transformation is hard to accept. My background in history led me to ask the obvious question; do transformations of this scale actually take place and, if they do, how do they progress? The resulting case studies each have their own distinct story but share some important characteristics. Among them is the stability, over long periods of time, of both the original transportation system and the mode that replaces it. Another striking characteristic is the speed at which transformations takes place. Above all  there are significant shifts in areas--economic, social, even cultural-- outside the transportation sector.    
Transportation is a unique sector of our economy for several reasons. It is a space where predictability is highly valued and levels of uniformity and standardization rarely seen in other industries are achieved. There is significant costs and risks associated with even minor innovations that leads to long periods of gradual and cautious change. On the other hand, the danger associated with  late adoption of  successful innovations contributes to rapid change in the transportation sector.  It shares with information technologies the potential for rapid change, but changes happen far less often. But because of its close integration with so much of the economic and social structure of societies, these changes have an even more dramatic  impact.
Another common thread is the potential value associated with the original transportation system, value that is increasingly made available to its replacement. Human capital, real estate, industrial capacity, all are potential accelerants for the expansion of a new transport mode. The transfer of these assets is tied up in the process whereby coexistence of two modes in an particular niche is replaced  with a predominance of one or the other. This may be the end of the process, or may just be the beginning of the story. This happens when a new technology has reach and can expand its influence beyond its original niche, and expand into other transportation sectors.


Horse Cart to Rail


It’s easy to see the advantage trains held over muscle power. Trains could carry larger loads further and more reliably than the horse drawn carts they replaced. While they lacked short haul flexibility, on longer trips their advantage was several orders of magnitude greater.
The challenges facing the development of rail technology are largely responsible for the drama accompanying its development. Railroads largely replaced a mode of overland transport that had existed for thousands of years. Social resistance to the introduction of steam power was well documented. Railroads were projects more capital intensive and technically complex than almost any previous human endeavor.
As a whole the railroad is a good example of the contingent nature of a new technology's ability to propagate effectively. A new technology alone -- in this case the reliable steam engine -- is not sufficient for its success. It required significant advances in fields that was already several hundred years old, from the mining and smelting of iron ore, to the use of new communication technologies such as the telegraph. Additionally, its growth would have been less dramatic without highly organized governmental structures ready to make the required capital expenditures.
It is clear as well that, once begun, the creation of railroads established conditions that accelerated its adoption. It created fear among nations that failure to have an extensive network would leave them vulnerable in time of war. It forced economies to invest in their production so as to have access to world markets. It drove the expansion of the Western world into previously inaccessible areas, providing both the raw materials and the manpower for further growth. In a historical instant, over the course of half a century, this new mode of transportation drove enormous change.


Omni Bus to Street Car


As a subset of the railroad revolution the rapid motorization of streetcars underlines the significance of the infrastructure as opposed to the vehicle that travels on it. With rails already established for the use of horse-drawn omnibuses the switch to motors was as rapid as the effects of the change were far reaching. This may have a great deal of relevance to the potential speed of transition to driverless vehicles which, initially at least, will utilize a pre-existing infrastructure. The relative outward similarity of the the original mode and the one replacing it is another obvious parallel.
It was a perfect storm in terms of mode replacement. All the pieces that make for rapid change in the transportation sector;  an existing infrastructure that was a perfect fit for the new mode, mature technology with fundamental advantages over what it replaced,  private and municipal structures with the incentive and capital to push the process. Wide and self reinforcing development drove the whole process forward efficiently and rapidly.
Horse Cart to Horseless Carriage
New York Street Scenes 1908-1938


Closely related to the rail revolution, the replacement of the horse by the internal combustion engine brought mechanical power to the “last mile” of transportation. Arguably this shift has been even more significant than any of the other modes so far examined.
Unlike rail transport, an increase in vehicle capacity or reliability cannot fully explain the rapid adoption of automotive transportation during the first half of the 20th century. There is again state investment in infrastructure, but on a regional (initially at least) rather than national level. Without the larger national motivations the take-up of the technology required buy-in from a much larger cross-section of the population as well.
Initial resistance to the mode was much greater as well. Although cars could use the same road infrastructure as horses, there were real and perceived conflicts between the two modes. The fragility of the automobile was in contrast to the ruggedness and simplicity of the horse.  Very few people saw the car as much more than a rich man’s toy, fewer still would consider it likely to be the cause of significant societal change.
The automobile revolution was as rapid as its ramifications were unforeseen. The car is perhaps our greatest example of the transformative power of innovation in the transportation sector. With the simple replacement of the horse with the internal combustion engine the entire pattern of urban and suburban development, economic activity, and society as a whole was redirected. Do we imagine that the wholesale replacement of the resulting automobile’s navigation, communication, and control functions with components orders of magnitude more efficient will create changes any less significant?  


Break-bulk to containers


Sometimes a transportation revolution is the result of timing as much as innovation. The simple idea behind containerization--standardization-- is not a new concept. By creating a seamless network connection between already mature transport modes--road , rail, and sea--it became the foundation of an unprecedented intensification of global trade. As a technology it is fairly simple, it is the infrastructure it supports that is complex.
The speed at which containerization became the dominant long distance freight mode obscures the enormous resistance to its adoption. The conservatism of the shipping industry, national and international regulations designed to minimize competition, and powerful labor unions, all worked to slow its spread. Where containerization gained a foothold, however, patterns of trade grew up around it. Increasingly those trade patterns shifted to those ports and trade routes that could provide the unprecedented speed and efficiency of containerized operations. In a remarkably short period of time ports around the world were forced to adopt new practices or sink into obscurity.  
Fortunately inter-modal transportation networks represent one of the most sustainable components of our transportation system. On aggregate they move more goods further with less emissions than single mode freight networks, largely reflecting the underlying efficiency of rail and maritime transportation. In the developed world at least it supports production capacity that marginally increases in efficiency on a steady basis. If anything, the practices standard to inter-modal transport would be beneficial if they could be more broadly used.
Of course it is also a clear example of the fact that each mode of transportation has a limited “reach”. That for a variety of reasons a mode that works well under one set of circumstances cannot be expected to be universally effective. While intermodal transport, and the containerization of freight, can provide enormously efficient transportation, it is limited to highly developed and intensively used networks, and almost entirely useless beyond those networks. In the underdeveloped world this means lack of access. In the developed world it means high volumes of goods reach distribution centers that transport networks struggle to move the “last mile” to their final destinations.
The story of containerization suggests that rapid and dramatic change can take place relatively quickly and on a very large scale. It illustrates that that change may develop from simple, but fundamental, technical innovations. Before we despair of finding a “silver bullet” to solve the challenges we face in reforming our transportation system we might find some reassurance in the story of containerization and the surprising opportunities that can develop from unexpected innovations.


CONCLUSION :    A Driverless Future


Roads are our great communal project. Today’s roads and the vehicles on them are the largest single infrastructure investment in human history. They are also the source of a myth that is central to our national self identity, the myth that driving gave us freedom.
But the truth is that no road, no system, has been equal to the ever increasing demands of our insatiable desire for movement. We find ways to fill every new capacity, to overload each available circuit. Every indication is that the demands on our transportation system will grow, in an accelerating fashion, year by year, for the indefinite future. This demand is driven by the needs, or desires, of countless individuals. As they access cars in ever greater numbers their needs are translated either into more pavement, more pollution, more gridlock, or all of the above.
The tools we possess to address the problems arising from this growth are largely unchanged for almost a hundred years. These tools are often seem to reflect a desire to return to older forms, often those which the present system replaced. Advances in technology seem to make marginal improvements in our transportation system. Our most realistic options appear to rely on political will  and time, in an effort to modify the very shape of the fabric of society itself. Through intensive development we hope to bring people, jobs, and resources into such close proximity that transit modes other than the car will provide effective service.There is, however, a real question is how much time we really have. And in the context of this limited time period how realistic these options options there really are.
It is important that every potential improvement to the sustainability of our transportation system be given appropriate attention. I believe that autonomous vehicles are at a point where their viability and increasing investment should lead us to, if not focus, at least keep an eye on their progress. And if over the next ten years they continue to develop as rapidly as they have in the last five there may be a real cause for excitement that a useful new tool is becoming available to pursue sustainability goals.


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Levinson, M., 2006. The box : how the shipping container made the world smaller and the world economy bigger, Princeton  N.J.: Princeton University Press. Available at: http://uwashington.worldcat.org.offcampus.lib.washington.edu/title/box-how-the-shipping-container-made-the-world-smaller-and-the-world-economy-bigger/oclc/62161116&referer=brief_results [Accessed January 29, 2012].
Nordahl, D., 2008. My kind of transit : rethinking public transportation in America 1st ed., Chicago: Center for American Places at Columbia College in association with the Elizabeth Firestone Graham Foundation  ;Distributed by the University of Chicago Press. Available at: http://uwashington.worldcat.org.offcampus.lib.washington.edu/title/my-kind-of-transit-rethinking-public-transportation-in-america/oclc/225875950&referer=brief_results [Accessed May 31, 2012].

White, R., 2012. Railroaded : the transcontinentals and the making of modern America, New York: W.W. Norton & Co. Available at: http://uwashington.worldcat.org.offcampus.lib.washington.edu/title/railroaded-the-transcontinentals-and-the-making-of-modern-america/oclc/785504427?referer=br&ht=edition [Accessed May 31, 2012].

Saturday, May 20, 2017

WSF? How Driverless cars will transform the Washington State Ferry System.



Driverless vehicles have the potential to reestablish the Washington State Ferry System to its historical role as a critical regional transportation network - halving trip times, doubling or tripling the capacity of the existing system - all without significant changes to boats or docks. Ferry facilities will take up less than 20% of the real estate they presently require when driverless vehicles become the norm.

All of which means that the Washington State Ferry system is an ideal example of the enormous disruption driverless vehicles are set unleash on regional transportation infrastructures.

The System Today 

Each region has its own set of unique transportation challenges, but few are as daunting as those facing the managers of Seattle/Tacoma's regional transportation network. Most serious are the numerous choke-points created by hills, canals, lakes, and, finally, by Puget Sound itself.  Moving north to south is difficult enough on the region's two (highly congested) primary freeways. But moving east to west, especially during rush hour in the Seattle urban area, is almost impossible.

JENNIFER JAMES

These large inland bodies of water, the results of a great glacial excavation project of previous millennia, were once the primary regional transportation network. While this inland marine waterway has made Seattle/Tacoma a primary ports for trade with Asia, it also constitutes an effective limit on Western Washington regional development. 

All this in spite of the fact that The Washington State Ferry system is the largest in the US (3rd worldwide), and moves almost a million cars every year. But for all that size it serves relatively small communities on the Western side of the sound, and supports little of the economic activity between them. It seems counterintuitive that driverless cars should have any significant effect on the function of a marine highway but in this case, like many others, drivers vehicles have an outsized potential making existing infrastructure operate with an entirely unprecedented dynamism.

To understand why this is so it's first necessary to understand how the existing infrastructure operates. The ferries are fast (typical transit time is not much more than 30 minutes) and large (up to 2500 passengers and 200 cars. Overall system capacity is impressive with 22 boats carrying up to 30,000 passengers every day.  Loading times for foot passengers are quite short and anyone arriving at the terminal 10 minutes before departure he would be assured of a spot on board. But any use of transit at either end adds a significant level of uncertainty. A driver, however, would have to budget at least half an hour more at the front end ( if all goes smoothly), 20 minutes more at the backend (for unloading), and significantly longer during rush hours, holidays, and game days. 

Attending Thanksgiving celebrations on the other side of Puget Sound (with family on Bainbridge Island) will include a nearly three hour return journey (2 hours in the car line, boarding, boat ride, disembarkation, ride home) to cover the distance of little more than 15 miles. My brother-in-laws daily commute is more typical - 10 minutes bicycle ride the front end, 30 minutes on the boat, and another 10 minutes bike ride on the Seattle side - a bit more than the national average but not by much.

Not that driverless vehicles will not make the boats go faster.  But the typical ferry route involves more time at the terminal then underway. And the terminals themselves represent almost as significant an economic investment than the ferries they serve. It is an examination of the potential to utilize driverless vehicles in the terminal-ferry interface is that gives us insight into the transformative potential of this new technology.

Loading walk on passengers is easy - an 8 foot wide gangway gets literally hundreds on board in minutes.  Cars load much more slowly however. When all goes well  the two lanes that feed the open ended ferry will allow it typical ferry to load 200 cars in under 20 minutes (@ 18/min). this rate is largely influenced by the fact that the process must be done at a speed which accommodates drivers of all skill and experience levels. The mix of vehicles is heterogeneous, and there is very little opportunity to organize them during the loading process. Unloading is faster (subject to traffic congestion at the destination), but not significantly so. 

The System in a world of Driverless Cars

Loading autonomous vehicles would be different in at least three significant ways; 

-The process would be more highly organized with vehicles moving in a highly predictable matter including higher speed and smaller spacing between vehicles. The final load configuration would be more uniform and significantly more efficient. Even without other advantages this would result in at least 25% time savings at the terminal.

-Vehicle loading and unloading could be synchronized. There are (at least) two lanes available and loading and unloading would be simultaneous. Time-saving here could be assumed to be significant as well, perhaps as much as another 25%.

-Passengers loaded directly onto the ferry without use of intervening modes. During the boarding/unloading process vehicles could board the ferry, discharge passengers, and leave the ferry, without significantly affecting turnaround times.

The halving of turnaround times at the terminal would result in at least a 25% reduction in trip times and increase of the number of trips at the ferry could take on a given day by about 25% to 35%. Most importantly the overall system capacity would see corresponding increases. Other potential improvements to ferry system infrastructure deriving from the development of autonomous vehicles include;
Reduced vehicle size and weight associated with driverless cars increase ferry loading.
Just in time arrival of vehicles to the ferry reduce the need for large holding areas.
Greater reliability leads to increased commercial use of ferries

The most significant effect in the long run, however, would derive from the effect of driverless based system on the passenger experience. The average car and transit user would see their overal commute time of well over an hour ( 30 min pre-board, 30 min trip,15 min off-load) decrease by at least 50%. Greatly increased reliability and shorter trips will attract greater numbers of users to the system, reduce the costs per user (or lower existing tax supported subsidies) and lead to an increase in regional economic activity. In short, the marine highway transformed into a Freeway, turning one of the major constraints on regional growth into a catalyst for sustainable development. 

Looking into the future often suggests a return to historical patterns. Before the advent of the automobile and an efficient highway system it was the Puget Sound's "Mosquito Fleet" of steamships that tied the growing towns of the region together. It should not be surprising then that this unique inland waterway will continue to play a significant, even expanded role during this next phase of development. Although it's certainly too early to begin working out the details of how to harness driverless technologies, the time is coming when a preliminary study should be done. System managers might be surprised at what they find.