Almost all trucks today are powered by diesel engines and fossil fuel. Changing how trucks are powered is essential to solving the problems of air pollution and climate change. After all, trucks account for a substantial share of both pollutant emissions and CO₂ emissions on California’s roadways. But what are the feasible strategies and costs for reaching a future with zero- or very-low-emissions trucks?

This question becomes even more challenging when focusing on “long-haul” trucks. Such trucks, typically tractor/trailer Class 8 vehicles weighing up to 33,000 pounds unloaded, can travel 500 miles or more per day, and have some challenging energy requirements—they must be able to carry enough energy, or have rapid access to it, to be able to travel these distances with up to a 40,000-pound payload.

From a regulatory perspective, the California Air Resources Board is in the process of proposing a new truck sales mandate that would require truck manufacturers to sell ZEV trucks, starting in 2024.

How can we power such vehicles with zero emissions? At the Institute of Transportation Studies at UC Davis, we strove to answer this question from a research perspective by looking at four technologies designed to provide power to long-haul trucks while producing zero tailpipe emissions. These technologies are: a catenary system; hydrogen fuel cells; dynamic inductive chargers embedded in the roadway (capable of charging moving trucks); and battery electric vehicles (BEVs). The first three of these are covered in a full report (here) and BEVs will be covered in an upcoming report.

We compared the technologies to each other and to a baseline diesel truck—in terms of technical requirements, current status, challenges, costs, and the potential for future improvements and scale-up. We considered both the vehicles and the energy infrastructure they would need to operate. We modeled a future (maybe 10 years out) where both trucks and infrastructure benefit from economies of scale. For our comparisons, we simulated a situation with 5000 trucks travelling 500 miles of roadway per day (which is a lot). We amortized the vehicle and infrastructure costs over this level of service and over many years (i.e., 20 years to pay off the infrastructure, 5 years for trucks with some resale value).

Though there are many factors affecting the comparison, and we consider a range of sensitivity cases, the figure shows our “base case” results: costs per mile for diesel and the first three technologies. The three cleaner technologies are all within 30% of the cost of diesel but none quite match it. The preliminary results for BEVs (not shown), based on slightly different assumptions, indicate that their total costs in a long-haul situation could be on the low side, ranging from $0.45–0.82 per mile versus $0.58 per mile for diesel.

In all cases the range of costs reflects uncertainties in vehicle costs, infrastructure costs, and energy costs. But it’s the energy costs (brown part of bars in the figure) that appear to be the most important and most uncertain. Electricity could run from $0.10 to $0.25 per kWh, depending on the nature of the contracts, whether pricing is closer to retail or wholesale, etc. Future hydrogen costs could vary from about $5 to $8 per kg (when derived from electrolysis), assuming large scale development and access to relatively inexpensive renewable power. The base technology, diesel, has a cost that is highly dependent on oil prices, which could range from $50 to $100/bbl or even higher. High- or low-end assumptions on each of these energy prices leads to a relatively good or poor position relative to the others.

Figure: Relative cost per mile of different technologies based on 500 miles of roadway.

But what exactly are these technologies? What are their advantages and disadvantages?

In the catenary system, overhead wires deliver power through a pantograph with electrical contacts rising off the top of the vehicle. Catenary systems have been widely used for light rail and trolleys, so the technology is well developed. Trials of catenary trucks are underway in Sweden and the Port of Los Angeles. The major challenges would be to install the infrastructure and provide another power source to trucks for when they leave wired roadways.

Dynamic inductive (or “wireless”) charging similarly provides electric power to moving vehicles, from a series of transmitting coils embedded in the roadway. The charge is delivered, with about 90% efficiency, over a short distance to a receiving coil on the bottom of a vehicle. The challenges and costs are like those of the catenary system, but this system would require installation of transmission coils in road beds. Like a catenary system, this system would require the installation of at least hundreds of miles of infrastructure before it would likely be sufficient to attract users—truckers willing to invest in the equipment needed to be compatible. Indeed, this chicken-egg dilemma is a factor for all four technologies: which comes first, investment in infrastructure or vehicles?

Hydrogen fuel cell (HFC) vehicles use hydrogen, as a liquid or compressed gas, to generate electricity from an on-board fuel cell. The hydrogen takes up less volume and weight than do batteries, and refueling is much faster than battery charging. A hydrogen system could also be scaled-up more cheaply and evenly than catenaries or inductive charging. However, infrastructure challenges are considerable in terms of the transportation (or on-site generation) and storage of hydrogen, as refueling stations would have to be 10–30 times larger than diesel stations. Two HFC trucks have been produced, the Vision Tyrano (200-mile range) and Nikola One (800- to 1200-mile range).

Battery electric long-haul trucks typically rely on plugging-in to be recharged (though we do assume some battery electric range for trucks accessing catenaries or dynamic induction systems). Most battery trucks currently have a range of less than 250 miles. The major challenges in applying this technology to long-haul trucks are the large quantity and weight of the required batteries. We estimate that about 1200 kWh would be needed, with a weight of well over 10,000 pounds. This means long recharging times and a potentially large reduction in payload (since battery weight takes away from what could be allocated for goods). In our analysis we assume some reductions in battery weight in the future and access to fast charging, but these two concerns remain.

As long as available electricity is from low carbon sources (namely renewables), the CO₂ emissions for catenary, dynamic inductive charging, and BEVs would be low. (The electric grid in California is targeted to be fully renewable by 2040.) The same is true for HFC trucks using electrolytically generated hydrogen, though in the nearer term, the lower efficiency of these trucks (and production of hydrogen) would mean higher CO₂ than the pure electric options. CO₂ would also be considerably higher if the hydrogen were derived from steam methane reforming of natural gas, which is common today.

In sum, each technology has several advantages and challenges, and there is no obvious winner. From the point of view of infrastructure needs and scale-up, hydrogen may have an advantage. Battery electric trucks provide an attractive option with lower infrastructure costs and potentially lower overall costs but would compromise payloads unless the weight of batteries comes down significantly or compromises are made on range. Finally, catenary and inductive charging systems could work best in areas of dense truck traffic but will need to be extensive enough to work for trucks covering many miles and will require the biggest up-front investments.

Two major questions that need further research are: How do we best manage scaling-up each technology? And how large will public investments and incentives need to be to create a self-sustaining system with adequate infrastructure? The UC Davis STEPS+ Program and Sustainable Freight Research Center will continue to work in this area.

This blog is drawn from a Caltrans “Planning Horizons” educational forum presented by Dr. Fulton this spring. To view a video of his presentation click here and select March 2019. To access the PowerPoint from the presentation click here. To access the full report that this blog and the talk are based on click here.

Note: This blog was originally published on 3/29/2019 by the legal news service Law360.

The automated vehicle revolution has begun, and will accelerate in the near future. AVs are vehicles that automate the act of driving. Many current-model cars already incorporate features such as adaptive cruise control, self-parking and lane-keeping assistance.

But a larger paradigm shift will occur in the near future when high-level AVs capable of full self-driving will reach some markets. Experts predict these vehicles will be safer than human-driven vehicles, but they will still sometimes crash and cause injuries.

The current auto liability framework works well for human-driven vehicles. However, it assumes a neat distinction between “the driver,” a human who is always responsible for controlling the vehicle, and “the manufacturer,” a company with no post-sale control over the vehicle.

Approximately 94 percent of car crashes are caused by human driver error; here, the human driver can be liable but the vehicle manufacturer cannot. Conversely, approximately 2 percent of car crashes are caused by a defect in the vehicle; here, the vehicle manufacturer can be liable but the human driver cannot. Both scenarios assume one party (but not the other) is presumptively “at fault” for a crash. Liability flows from this fault determination; fault flows from control.

In a self-driving car, however the vehicle’s true “driver” — the party actually controlling the vehicle — is not the human but the vehicle itself. Several recent AV prototypes do not even have a steering wheel or pedals for the human occupant to use. In this type of vehicle, the human vehicle occupant cannot exert control over the vehicle and thus cannot make a driver error. This is significant: in a self-driving car, the traditional pathway to human liability is foreclosed.

If the human driver cannot be liable, it is likely that liability will shift to the manufacturer. The bigger question, however, is whether the liability standard will also shift accordingly. Human drivers are typically evaluated under a negligence standard; manufacturers are typically evaluated under a strict products liability standard. As we shall explain, the combination of manufacturer-borne liability with a default products liability standard could threaten the societal gains we could achieve through AV usage.

The prospect of assigning all AV liability to manufacturers has theoretical appeal: After all, the manufacturer of the self-driving software is presumably the only party capable of controlling or improving the safety of the vehicle. And from an economic perspective, assigning liability costs to the manufacturer, the “cheapest cost avoider” in this scenario, should incentivize the manufacturer to maximize safety precautions. This would benefit AV consumers and to all other parties sharing the roads with these vehicles as well.

However, if we assign all AV liability to manufacturers, these manufacturers could incur significant liability costs. This strikes us as fundamentally fair: If manufacturers want the financial benefits of selling a proprietary and potentially dangerous product, they should assume the financial risks associated with the product as well. The problem is not the assignment of liability; it is the assignment of litigation costs. Products liability litigation is notoriously time-consuming and difficult — thus, invariably, expensive.

Applying products liability to self-driving cars will not benefit most victim-plaintiffs. Given that AV technology is proprietary, and assuming that manufacturers will fight to protect their source code from discovery, it is not clear where a plaintiff will be able to find a qualified expert who can identify the particular software error that yielded a particular crash. And even if such an expert were available, the legal costs of launching a products liability lawsuit may easily exceed most routine damage claims. Attorneys, not victims, will reap the benefits of this system.

Products liability will also be costly for manufacturers. Even if we are comfortable with manufacturers assuming the costs of victim compensation, the frequency and costliness of defending against products liability lawsuits is problematic for two reasons. First, those litigation costs will ultimately be passed on to consumers, driving up the cost of AV use and ownership. Second, these litigation costs may force smaller manufacturers out of the market, creating oligopoly.

Both of these situations would likely reduce the number of AVs on the road. And if, as we predict, the use of AVs is a net positive for society — if AV usage can improve road safety, increase access to mobility, reduce vehicle emissions, aid in the movement towards sustainable city design, etc. — then the last thing we should want to do is create a liability system that reduces the quality and quantity of available AVs.

The solution to this problem is to create a manufacturer liability standard that is less costly to both victims and manufacturers. We suggest a manufacturer negligence standard. Here, when an AV crashes, the court could assess the vehicle’s actions under the “reasonable human driver” standard. Thus, if the AV’s actions would be deemed negligent if performed by a human driver (for example, speeding or disobeying a traffic signal), the manufacturer would be liable.

The value of this system is that the court’s analysis could be focused on the crash itself — what the vehicle actually did — rather than analyzing the self-driving software’s source code to determine whether the vehicle was defectively designed. This would be a much easier and less time-consuming (thus cheaper) analytical mode for all parties.

An alternative solution might be to create a victim compensation fund, allowing injured victims to bypass the courts and products liability altogether. This fund could be created from mandatory contributions from manufacturers in proportion to each manufacturer’s market share, or each manufacturer’s share of total AV crashes. A compensation fund could also help victims recover for their injuries more quickly and with less uncertainty than through the litigation process.

If AVs are better for society than human-driven vehicles, we should design our liability to promote their usage. Products liability is simply too costly — both in terms of financial costs and also in terms of the value lost by reducing AV usage — to be the proper legal standard for analyzing AV crashes.

This blog is based on a series of four 2019 issue papers on possible approaches to liability and insurance for automated vehicles.

Gordon Anderson is a legal fellow at the UC Davis Policy Institute for Energy, Environment, and the Economy and a third-year student at King Hall, UC Davis School of Law.

Austin Brown is executive director of the Policy Institute. In this role he builds strong connections between the research and policy communities at the local, state, and national levels with a focus on clean energy and sustainable transportation.

On Tuesday, February 26, ITS-Davis’ founding director and California Air Resources Board (CARB) member Daniel Sperling was the first to testify on one of two panels before the U.S. Congressional House Committee on Transportation & Infrastructure at a hearing entitled “Examining How Federal Infrastructure Policy Could Help Mitigate and Adapt to Climate Change.” Dr. Sperling shared his “experiences from California” and “insights from over 30 years studying the transportation system of this country.”

Throughout his testimony, Dr. Sperling identified policy strategies for promoting more environmental, equitable, and efficient transportation in ways that support the economy and promote innovation without necessarily burdening taxpayers. He said, “The point of this hearing and my testimony, is to address the goal of aligning transportation spending with environmental goals—as well as with social goals.”

In his opening comments, he highlighted how the current transformative revolutions in transportation—electrification, automation, and shared mobility—present government with the challenge and opportunity to “refocus and restructure how we fund and manage our transportation system, such that we direct these many innovations toward the public interest.” A key role for government in supporting innovations is to support “pilot and demonstration programs” to enable necessary experimentation.

Other members on the panel included Vicki Arroyo, of the Georgetown Climate Center; Thomas P. Lyon, of the Stephen M. Ross School of Business, University of Michigan; Ben Prochazka, of the Electrification Coalition; and Nancy Young, from Environmental Affairs at Airlines for America. Ms. Arroyo, whose organization has partnered with ITS-Davis on several events and initiatives, spoke about how multiple states and cities have implemented programs that are “promoting adoption of cleaner vehicles and fuels, improving public transportation, and enacting pathways to fund clean transportation innovation.”

After opening remarks from each of the five panel members, congressional members asked questions and spoke about their concerns over a two-and-a-half-hour period. During this Q & A, Dr. Sperling responded to questions posed by representatives including Julia Brownley (D-CA), Mark DeSaulnier (D-CA), Alan Lowenthal (D-CA), Pete Stauber (R-MN), Lizzie Fletcher (D-TX), Abby Finkenauer (D-IA), and Salud Carbajal (D-CA), who recognized Dr. Sperling for his “testimony and leadership on reducing greenhouse gas emissions.”

In responding to questions, Dr. Sperling highlighted California’s policies and programs that could inform federal policies to promote sustainable transportation. For example, he described how the California Cap and Trade Program “funds probably $1B per year in clean transportation and is also used for affordable housing near transit stations and the greening of communities to reduce emissions—with no taxpayer money.”

Dr. Sperling was also asked about his recommendations regarding “carrots and sticks” in policies to promote sustainable transportation, such as the Sustainable Communities and Climate Protection Act (SB 375). He emphasized the importance of carrots: “We need to reward communities that invest in putting in more chargers, bike lanes, transit, etc., because they don’t have the resources.” He added: “That is my biggest plea, to somehow restructure transportation funding so it acknowledges and rewards these environmental goals as well as the vehicle-miles travelled goals.”

Click on the following links to view: video footage of the entire hearing and Dr. Sperling’s written testimony and opening statement.

Seth Karten is a science writer for the Institute of Transportation Studies at UC Davis.

Every January, transportation researchers from across the globe descend on Washington, D.C. for the Transportation Research Board (TRB) Annual Meeting, the largest transportation research conference in the U.S. and possibly the world. The 13,000 attendees at TRB 2019 featured a significant contingent of researchers and staff from UC Davis who shared their insights and findings at meeting sessions.

This year, we wanted to do more than that, making sure that legislators and regulators in the area benefited from UC Davis expertise as well. To that end, representatives from the Institute of Transportation Studies at UC Davis (ITS-Davis) and the Policy Institute for Energy, Environment, and the Economy (Policy Institute) met with 15 congressional offices and held two briefings in the House and Senate buildings to share research findings with dozens of key policy leaders at federal agencies. Our goal was not to lobby for any particular policy outcome but rather to provide policymakers with insights that can inform decision-making. It’s all part of our mission to ensure that leading research and sound policy are made inseparable.

Kelly Fleming joined fellow Policy Institute and ITS-Davis staff and researchers for meetings with members of the U.S. House of Representatives California delegation. She is pictured here (second and third from left, respectively) at meetings with Reps. Mark DeSaulnier and Allen Lowenthal. UC Davis transportation experts also spoke with Reps. Doris Matsui, Ami Bera, and John Garamendi.

Our first briefing, hosted by the 3 Revolutions Policy Initiative—held in the Rayburn House Office Building—was entitled Governance Needs and Opportunities and featured findings from a recent issue paper, “Federal, State, and Local Governance of Automated Vehicles.” Experts presented to a packed room on how vehicle automation will challenge the way we manage vehicles and transportation. The briefing included a discussion of options for integrating automated vehicles into transportation systems in ways that will yield widespread societal and environmental benefits. Speakers included Austin Brown and Mollie D’Agostino of UC Davis, Greg Rodriguez of Best Best & Krieger, Natasha Vidangos of the Alliance to Save Energy, and Scott Goldstein of Transportation for America (Tweet of briefing with pictures).

The National Center for Sustainable Transportation (NCST), a federally funded University Transportation Center based at UC Davis, held a second briefing in the Dirksen Senate Office Building to discuss recent research findings related to sustainable transportation and new transportation technologies, such as automation. The briefing was hosted by Colin Murphy of NCST, and featured UC Davis researcher Alan Jenn of the Plug-in Hybrid and Electric Vehicle (PHEV) Center, who addressed the effectiveness of electric vehicle incentives. NCST researcher Carol Vallett of the University of Vermont spoke about how state Departments of Transportation can build and maintain a workforce capable of meeting 21st-century transportation challenges (Tweet of briefing with pictures).

ITS-Davis researchers and Policy Institute staff also met separately with members of Congress and their staffs to discuss transportation topics that are likely to arise during this legislative session, discuss relevant research, and identify knowledge gaps that UC Davis can help fill to support smart transportation policy. UC Davis researchers spoke in person with Representatives Ami Bera, Mark DeSaulnier, John Garamendi, Allen Lowenthal, and Doris Matsui. Transportation and energy staff from another 10 offices also met with ITS-Davis representatives over the course of the week. Figuring out how to support the transition to electric vehicles was a common theme in these conversations, as was understanding how automation and e-commerce are changing how goods and people move. These topics will be explored in greater depth at the upcoming Three Revolutions Policy Conference in Davis on March 18–19th, to be keynoted by Rep. Matsui.

The rapid evolution of transportation systems and technologies in recent years has created new legislative opportunities and needs, such as electric-vehicle incentives and automated-vehicle regulation. Congress is expected to address many of these in the near future. Ensuring that policymakers are aware of and understand key insights from research on emerging transportation topics will do much to facilitate the success of future policies. ITS-Davis, the Policy Institute, and numerous other institutes and centers at UC Davis are well-positioned to help on this front.

UC Davis is home to some of the world’s leading experts on transportation, energy, and climate. By taking the time to build ongoing relationships with policymakers working on issues in these areas, UC Davis is supporting development and deployment of successful solutions to some of society’s most pressing needs.

Kelly Fleming is an energy and transportation analyst for the UC Davis Policy Institute for Energy, Environment, and the Economy.