Why Consider Novel Transportaton Modes?
The U.S. transportation system offers historically unprecedented levels of mobility, but the research team noted that it does not meet the needs of all users and comes with significant financial and other costs. In accordance, transportation operators and the traveling public are constantly searching for improvements in speed, access, safety, and environmental performance.
Over the past few decades, capacity expansion constraints, funding limitations, and shifting public preferences have led to a focus on improved system management over new construction, particularly by making use of newly available information and communication technologies. Although real improvements in performance have been made, the surface transportation system continues to face significant issues with congestion and emissions. There are also other emerging challenges, such as preserving mobility for an aging population. In accordance, government and industry may benefit by considering an entirely new approach.
New products and services are sometimes described as arising from a combination of societal or market “pull” and technology “push.” The former refers to products that are explicitly designed to address unmet needs or other opportunities in the market, whereas the latter refers to a process by which new products are designed primarily to take advantage of technological advances. The following pages summarize key societal and technological factors in transportation innovation today.
Societal Pull Factors
Although the current surface transportation system provides users with high levels of personal mobility, it has significant shortcomings that could create demand for novel modes. In particular, the current surface transportation system is costly in terms of expenditure levels and its impacts on human health and the natural environment. In addition, the current system leaves segments of the population underserved. The key limitations noted by the research team are outlined in the following sections.
The Bureau of Transportation Statistics estimates that the United States collectively spends approximately $800 billion per year on motor vehicles, fuels, and related items.(2) At the household level, an estimate from the Census Bureau puts the annual spending total for vehicles, fuel, and other vehicle expenses at approximately $8,466 per household, which is higher than food and any other expense category except for housing and shelter.(3) The American Automobile Association separately estimates the direct financial costs of driving a family sedan at approximately $0.59 per 1.6 km (1 mi) or just under $9,000 per year for a typical driver.(4) For many households, maintaining basic mobility, including access to jobs and services, requires one or more vehicles with costs that can consume a significant share of disposable income.
Public Infrastructure Costs
Public sector expenditures on roads, bridges, and other infrastructure include roughly $40 billion per year from Federal-aid programs under the current Moving Ahead for Progress in the 21st Century Act, in addition to an estimated $250 billion in State and local expenditures.(5) According to FHWA’s Conditions and Performance Report, these levels are not adequate to maintain the road system in its current condition nor to reduce the backlog of deferred maintenance.(6)Other public costs, such as emergency response related to traffic crashes and police costs associated with traffic control and enforcement, are harder to quantify but are undoubtedly substantial. The financial demands of maintaining the country’s enormous roadway infrastructure are such that the potential insolvency of the Highway Trust Fund continues to be a pressing issue.
Limited Options for Non-Drivers
The interaction between the current surface transportation system and the low-density development patterns typical in the United States has meant that those who are unable to drive (e.g., because of age or disability) and those who cannot afford or do not want to own a car have fairly limited mobility options or are constrained in their choices of living and working locations. This presents a very large societal cost in terms of foregone employment opportunities, limited access to services, and more broadly in reduced community cohesion.
According to the National Highway Traffic Safety Administration report, Traffic Safety Facts 2013, 30,057 fatalities and just under 1.6 million nonfatal injuries resulted from traffic crashes in 2013. This equates to 10.35 deaths per 100,000 people, which compares unfavorably to other highly developed countries and represents a very large societal cost.(7) Although much progress has been made over the past decades, motor-vehicle crashes are still the leading cause of death for several age groups.
The United States is the second largest emitter of greenhouse gases (GHGs) after China, and approximately 20 percent of those GHGs come from surface transportation, principally cars and trucks. The United States has announced a target to reduce GHG emissions by 26–28 percent below 2005 levels by 2025.(8)Emissions of criteria pollutants as designated under the Clean Air Act have been reduced considerably in recent years but continue to contribute to health problems, such as asthma.(9)
Another source of societal pull factors could come from demographic and attitudinal changes toward transportation. For example, driver license and vehicle ownership rates among younger Americans have declined, and there is some evidence that this group is more open to innovative approaches, such as bike sharing and ride sourcing. This group could serve as a source of demand-side pull for novel surface transportation systems as an alternative to car ownership or conventional transit services.
Over the long term, broader societal trends could also spur interest in new forms of transportation. These could include changes in settlement patterns, employment locations, or freight flows that stretch the limits of existing transportation systems. Likewise, challenges with security, public health, resource constraints, or adaptations to a changing climate could also lead to interest in new modal options. More optimistically, rising personal incomes over time would also tend to foster interest in transportation systems that offer travel-time savings, greater convenience, or productivity improvements. This dynamic, and other key points about societal pull factors, are distilled in table 1.
|Current Transportation Systems||Future and Emerging Transportation Systems|
|Current Societal Needs||Existing systems provide high levels of mobility and convenience but at high cost and with notable limitations.||Future systems would need to be cheaper, safer, faster, more comfortable, and more convenient than is the current set of transportation options.|
|Future and Emerging Societal Needs||Current modes may not be able to adapt to future needs or societal changes.||Future systems would be developed to respond to new and emerging needs (e.g., for independent mobility for growing elderly population).|
Technological “Push” Factors
Technological innovation can drive transportation development and innovation. Recent technological advances of particular relevance to transportation include improvements in wireless communications to vehicles in real time and other wireless transmission (e.g., electrical charging), continued advances in computing power that enable real-time processing of large amounts of information, materials science innovations in lightweight composites and solar charging, and new business models for transportation services (e.g., vehicle sharing and pop-up services).
Improved communications, new sensor technologies, and computing power are driving advances in partial or complete automation of vehicles. Automated vehicles are defined as those vehicles in which at least some aspects of a safety–critical control function (e.g., steering, throttle, or braking) occur without direct driver input. Automated vehicles may use onboard sensors, cameras, global positioning systems, and telecommunications to obtain the information necessary to make judgments regarding safety–critical situations and act appropriately by effectuating control at some level.(10) Although fully-automated (i.e., driverless) vehicles may be many years away, automation has progressed rapidly, and a growing share of vehicles on the market today already have limited forms of automated control (e.g., adaptive cruise control, lane-keeping, and forward-collision avoidance). Potential benefits of automation include improvements in safety and a reduction in accident rates; improvements in traffic flow and fuel efficiency by using sensors and communications to maintain headways; reduced travel times because of reduced congestion, accidents, and arbitrary driver behaviors that cause bottlenecks; and improvements in air quality. Such systems leverage current infrastructure and vehicle ownership models while taking advantage of automation to reduce error and improve system efficiency.
Recent advances in inductive charging of batteries have attracted a great deal of attention for transportation uses, such as charging of electric buses during routine stops and in pavement charging options. Inductive charging, also called wireless charging, is the transfer of a charge from one electrical system to another in close proximity by creating an electromagnetic field in the power source to induce an electromagnetic charge into a destination device. The advantage to this mechanism is that it can be done simply by proximity and does not require vehicles to stop and plug in to a fixed electrical outlet. Inductive charging is considered key to the future of electric vehicles to overcome barriers, such as lack of personal charging space and locations, length of the charging period, and the desire to charge while driving. Inductive-charging mechanisms also have a greatly reduced risk of electric shock; however, they tend to be less efficient because they lose charge as waste heat and need to power the charging source as well as the destination. These charging mechanisms can be slower to charge, but transmission efficiency can approach that of wired systems when coils are of a similar size and in close proximity.(11) Technologies are also improving to reduce losses. For example, several inductive charging systems have been successfully demonstrated in transit environments in the United Kingdom, Germany, Italy, and Korea.(12) The Society of Automotive Engineers is also developing a standard frequency and minimum performance, safety, and testing criteria for inductive charging of electric vehicles, which is expected to further innovation in this area.(13) Many of the current impediments to broader electric-vehicle (EV) adoption relate to the vehicles’ limited range and the time and dedicated locations needed for recharging. The extent that widespread, cost-effective, inductive-charging systems can be developed would likely significantly increase EVs’ market penetration relative to internal combustion vehicles. In time, motorists could recharge their vehicles while driving or cordlessly recharge at office parks and shopping centers.
Advances in materials science may contribute to both propulsion and construction materials in existing vehicles. A variety of thin-film photovoltaic materials are in development that will be lightweight and cheaper to construct than traditional photovoltaic cells. These materials may become part of vehicle windows and surfaces in the future to assist in propelling the vehicle with renewable solar power. Advances in battery and energy storage technologies, such as organically-based batteries that can recycle spent lithium and batteries with increased efficiency and reduced toxicity, may further enable the expansion of EVs by increasing range, reducing cost, and improving environmental footprints.(14) Novel composite materials will also increasingly enable the production of lighter weight vehicles with better fuel economy and similar or better safety profiles than current vehicles. The Department of Energy (DOE) estimates that a 10-percent reduction in road vehicle weight can lead to a 6–8 percent fuel-efficiency improvement and suggests that high-efficiency engines made of advanced materials can also lead to improvements in efficiency. In addition, DOE estimates that the combination of reduced weight and engine improvements associated with advanced materials could save over 5 billion gallons of fuel annually by 2030.(15)
Recent developments in vehicle sharing (e.g., car and bicycle sharing) and pop-up ride services that respond to immediate requests (e.g., taxi services such as Uber and bus services such as Bridge) have begun to dramatically alter how a significant segment of the population travels.(16) All of these services depend on improved wireless communications, mobile phone applications, global positioning systems, electronic payment systems, and access to an ad-hoc workforce. As of 2011, over half a million people in the United States and Canada participated in car-sharing services.(17) Survey results suggest that for a certain portion of users, car sharing led to a new lifestyle involving an increase in travel by non-motorized travel modes and public transit in concert with their increased use of car sharing. Other segments of the population, particularly those who began car-sharing membership as carless households, exhibited a decrease in public transit use.(14)