research report

Pavement Environmental Life Cycle Assessment Tool for Local Governments

Abstract

The processes in the pavement life cycle can be defined as material extraction and production; construction; transport of materials and demolition; the use stage, where the pavement interacts with other systems; the materials, construction, and transport associated with maintenance and rehabilitation; and end-of-life. Local governments are increasingly being asked to quantify greenhouse gas emissions from their operations and identify changes to reduce emissions. There are many possible strategies that local governments can choose to reduce their emissions, however, prioritization and selection of which to implement can be difficult if emissions cannot be quantified. Pavement life cycle assessment (LCA) can be used by local governments to achieve the same goals as state governments. The web-based software environmental Life Cycle Assessment for Pavements, also known as eLCAP has been developed as a project-level LCA tool. The goal of eLCAP is to permit local governments to perform project-level pavement LCA using California-specific data, including consideration of their own designs, materials, and traffic. eLCAP allows modeling of materials, transport, construction, maintenance, rehabilitation, and end-of-life recycling for all impacts; and in the use stage, it considers the effects of the combustion of fuel in vehicles as well as the additional fuel consumed due to pavement-vehicle interaction (global warming potential only). This report documents eLCAP and a project that created an interface for eLCAP that is usable by local governments.

research report

Pooled and Shared Travel in the Wake of the Pandemic: An Inventory and User and Expert Assessments of Vehicle Design Strategies to Mitigate Risk of Disease Transmission

Abstract

This project involved the development of a COVID-19 Risk-mitigating Vehicle Design (CRVD) typology to summarize and analyze the wide variety of vehicle design strategies that have been implemented or suggested to reduce the risk of COVID-19 transmission among workers and passengers in shared and pooled vehicles. Public transit and shared mobility service operators can use the CRVD typology as a reference and guide to aid decision-making in their continued response to the pandemic as well as for future planning. The typology also serves as a launching point for further innovation and research to evaluate the effectiveness of CRVD strategies and their relationship to user preferences and travel behavior, again both within and beyond the current context. This research also explored layperson and expert perceptions of the identified CRVD strategies. By combining these perspectives, a holistic frame can be created to start to develop optimal vehicle design solutions that would be both objectively effective in preventing COVID-19 spread and making travelers feel safe. Ultimately, the hope is that this research can help support a safe return to shared and pooled travel in the wake of the pandemic and contribute to a better—more equitable, sustainable, and enjoyable—mobility future.

conference paper

Climate and Fiscal Impacts from Reduced Fuel Use during COVID-19 Mitigation

Abstract

In 2015, the Road Ecology Center at UC Davis developed a web-based method to collect all incident data that appear on the CHP real-time incident-reporting website (https://cad.chp.ca.gov/). These data are assembled into a database called CHIPS, the California Highway Incident Processing System. Previous analyses suggest that these data are more spatially accurate than other state resources (e.g., the Statewide Integrated Traffic Records System (SWITRS)). Because they are collected and organized in real time, they can also be shared and queried more easily. The current project developed a web portal that supports queries for counties and specific highways (https://roadecology.ucdavis.edu/resources/covid19- traffic). The results shown make apparent the reduction in crashes and traffic during the summer 2020 peak of the COVID-19 pandemic.

conference paper

Impact of COVID-19 on Traffic, Crashes, and Wildlife-Vehicle Collisions

Abstract

In 2015, the Road Ecology Center at UC Davis developed a web-based method to collect all incident data that appear on the CHP real-time incident-reporting website (https://cad.chp.ca.gov/). These data are assembled into a database called CHIPS, the California Highway Incident Processing System. Previous analyses suggest that these data are more spatially accurate than other state resources (e.g., the Statewide Integrated Traffic Records System (SWITRS)). Because they are collected and organized in real time, they can also be shared and queried more easily. The current project developed a web portal that supports queries for counties and specific highways (https://roadecology.ucdavis.edu/resources/covid19- traffic). The results shown make apparent the reduction in crashes and traffic during the summer 2020 peak of the COVID-19 pandemic.

published journal article

Driving and Charging Electric Vehicles on Ride-hailing Services in the United States

Abstract

Electrification of transportation network companies (TNCs), such as Uber and Lyft, can produce social and environmental benefits from reduced vehicle emissions and enhanced implementation of renewable electricity as well as private benefits to drivers via reduced vehicle fuel and maintenance costs compared to conventional vehicles. We conducted a survey of plug-in electric vehicle (PEV) drivers on the Uber platform in the US. This paper describes these drivers and their experiences to further understanding of motivations for and barriers to PEV adoption among TNC drivers. The TNC-PEV drivers in this sample clearly recognized, and were largely motivated by, economic benefits of fuel and maintenance savings, thus, increased net earnings, associated with using a PEV to provide ride-hailing services rather than a conventional internal combustion engine vehicle. Most drivers reported charging their PEV every day, most often at home and overnight. This is true even of those with plug-in hybrid electric vehicles (PHEVs) that can run on gas if not charged. Increased electric driving range topped the list of drivers’ wishes to better support PEVs on TNCs, and range limitations topped the list of reasons why PHEV drivers did not opt for a battery electric vehicle (BEV; that runs exclusively on electricity). The second most common wish among all PEV drivers was for more charger locations.

white paper

Practitioner Guide: An Inventory of Vehicle Design Strategies Aimed at Reducing COVID-19 Transmission in Public and Private Pooled and Shared Transportation

Abstract

The COVID-19 pandemic has had dramatic impacts on transportation globally, reducing travel and deterring travelers from using shared and pooled modes such as public transit, carpooling, car-sharing, pooled ride-hailing, and micro-mobility. These modes are critical components of a decarbonized and equitable mobility future, but already comprised a small fraction of pre-pandemic travel in the U.S., and will likely remain further suppressed in the wake of the pandemic if people continue new mode choice habits. Those who do continue to rely on public transportation are disproportionately at risk due to the degree to which these modes leave them susceptible to disease transmission. For pooled and shared travel to return to and ideally surpass pre-pandemic levels, it is important to implement solutions to reduce the real and perceived risks of infectious disease transmission. This white paper presents an inventory and typology of vehicle design strategies that have been proposed or implemented with the aim of mitigating the risk of COVID-19 transmission in pooled and shared travel modes. Researchers organized these strategies into a COVID-19 Risk-mitigating Vehicle Design Typology and identified the mechanisms by which they may help diminish the risk of COVID-19 transmission. It is intended as a resource for policy-makers, transportation service operators, vehicle manufacturers, and scientists who are tasked with evaluating strategies to mitigate disease transmission risk in shared and pooled transportation services

policy brief

New UC Davis Model Shows Promise in Identifying Optimal Locations of Hydrogen Refueling Stations for Medium- and Heavy-Duty Trucks in California

Abstract

Researchers at UC Davis developed “Spatial Transportation Infrastructure, Energy, Vehicles, and Emissions (STIEVE),” an optimization model for hydrogen refueling stations in California. The model uses inputs from the California Statewide Travel Demand Model (CSTDM) and other sources to determine heavy-duty vehicle travel demand across the state, and the corresponding, localized energy demand. The model then determines which of the transportation analysis zones (areas based on census geography used to replicate areas of trip origins and destinations) delineated by the CSTDM are optimal areas for refueling stations and the number of stations needed in each zone to meet demand while minimizing costs. The final step is a suitability analysis that identifies each station’s specific location within a designated transportation analysis zone, based on a determined footprint for the refueling station.

research report

Making Transit Safe to Ride During a Pandemic: What Are The Risks and What Can Be Done in Response?

Abstract

The Covid-19 pandemic dramatically curtailed travel in the spring of 2020 and more moderately in the months that followed. Travel on public transport declined more and remains lower than on other travel modes, such as driving, biking, and walking. Although public transit operators have implemented various measures to reduce the risk of infection for both riders and employees, the fear that public transport poses a high risk for transmission of infectious disease is widespread. Since the onset of the Covid-19 pandemic, debates have raged in the popular and academic literature regarding the safety of public transit systems and the role they may play in spreading the disease. To inform this debate, the research team reviews the public health literature on the spread of communicable diseases on public transport and concludes that current debates over public transit safety with regard to infection risk have tended to simplify a complex question that depends on numerous factors, many of which are well beyond the control of public transit operators. The paper draws on published studies of previous epidemics and the current pandemic to show that 1) there is a risk of infection on public transport, but the relative magnitude of the risk is often lower than in many other settings including households, workplaces, schools, restaurants, and hospitals; 2) both the broader public health response and public transit agency actions can meaningfully reduce the risks of transmission; and 3) public transport (and indeed all travel modes), by moving people from one place to another, can facilitate the geographical propagation of infections, which can be effectively limited by travel restrictions. The team highlights the multitude of risk factors that can affect infection risk on public transport and argues that public transit systems can be made safe by actions taken by individual riders, public transit operators, and, most importantly, by community-wide public health responses.

research report

Who Has Access to E-Commerce During the COVID-19 Pandemic in the Sacramento Region? Implications for Future E-Commerce and Shopping Tripmaking

Abstract

The COVID-19 pandemic brought about dramatic shifts in travel, including shopping trips. The research team investigated changes in e-shopping for food and non-food items by supplementing an April to May 2018 household travel survey (n=3,956 households) conducted by the Sacramento Area Council of Governments (SACOG) with a May 2020 follow-on panel survey (n=313 households) during one week early in the pandemic. Results demonstrate that impacts from added pickups and deliveries in the SACOG region during the first two months of the COVID-19 pandemic were limited and did not overwhelm curb management at retail, restaurant, and grocery establishments. Results also show that during the pandemic e-commerce tended to replace non-food shopping trips, but complemented restaurant and grocery trips. However, Forty percent of the sample households — predominantly lower income and/or older populations — still shopped only in-store for food while more affluent households appear to have isolated themselves from virus exposure through more extensive online shopping. The researchers recommend extending the forms of accepted payment for online shopping and reducing fees and markups based on payment methods to reduce barriers to online shopping for those with limited resources. The research paper identifies possible consequences (e.g., more vehicle miles traveled and higher demand for curbside parking) if e-commerce food purchasing continues to grow post-pandemic or if in-person retail shopping returns to normal.

research report

Synergies of Combining Demand- and Supply-Side Measures to Manage Congested Streets

Abstract

An agent-based, multichannel simulation of a downtown area reveals the impacts of both redistributing traffic demand with time-dependent congestion pricing, and supplying extra capacity by banning left turns. The downtown street network was idealized and loosely resembles central Los Angeles. On the demand side, prices were set based on the time of day and distance traveled. On the supply side, left-turn maneuvers were prohibited at all intersections on the network. Although both traffic management measures reduced travel costs when used alone, the left-turn ban was much less effective than pricing. When combined with pricing under congested conditions, however, the left-turn ban’s effectiveness increased considerably—it more than doubled in some cases. Furthermore, the two measures combined reduced travel costs in synergistic fashion. In some cases, this synergistic effect was responsible for 30% of the cost reduction. This strong synergy suggests that turning bans should be considered as an added option when contemplating congestion pricing.