Shared micromobility (e.g., e-scooters, bikes, e-bikes) offers moderate-speed, space-efficient, and “carbon-light” mobility, promoting environmental sustainability and healthy travel. While the popularity and use of shared micromobility has grown significantly over the past decade, it represents a small share of total trips in urban areas. To better understand shared micromobility ridership, researchers from across the U.S. and the world have analyzed statistical associations between shared micromobility usage and various explanatory factors, including socio-demographic and -economic attributes, land use and built environment characteristics, surrounding transportation options (e.g., public transit stations), geography (e.g., elevation), and micromobility system characteristics (e.g., station capacity). To understand what these studies collectively mean in terms of expanding shared micromobility usage, we conducted a meta-analysis of 30 empirical studies and then developed robust estimates of factors that encourage ridership across different markets.
Considerable advancements have been made in traffic management strategies to address highway congestion over the past decades; however, the continuous growth of metropolitan regions has impeded such progress. In response, transportation planners have given special attention to integrated corridor management (ICM), an approach that coordinates various traffic control units (e.g., ramp metering) to optimize their operations along the entire freeway. Emerging connected vehicle (CV) technology is expected to substantially benefit ICM, where vehicles can communicate with each other and surrounding roadway infrastructure. The combined potential of ICM strategies and CVs could be even greater if combined with strategies that leverage underutilized infrastructure (specifically park-and-ride facilities) to reduce the total number of vehicles on the roadway.
There is growing international interest in electrolytic hydrogen produced from renewable energy (often referred to as green hydrogen) as a potential zero-emission alternative to gasoline and diesel in a variety of on-road and off-road transportation applications. Currently, gasoline and diesel are priced around $4 per gallon at the pump and a gallon of either fuel is roughly the equivalent of one kilogram of hydrogen based on energy content. Although hydrogen vehicles are generally more efficient than those fueled by petroleum, transporting and dispensing hydrogen is more expensive than for conventional fuel, so hydrogen must reach a cost substantially below $4/kg, possibly as low as $2/kg, to be a cost competitive option. Is this achievable? In short, this depends on the extent to which green hydrogen markets scale up globally. Projections of future green hydrogen production costs are generally in the range of $2–$4/kg by 20301 ; however, some expect faster and deeper declines reaching as low as $1.5/kg by 20302 and even $1/kg by 2030 under ideal conditions.3 This brief examines the evidence in support of green hydrogen production achieving a cost at or below $2/kg starting from its current level of between $5 and $6/kg,4 and assesses the time point at which this cost benchmark could be achieved.
California’s legislature has attempted to address the state’s housing affordability crisis in recent years by adopting numerous laws encouraging new development in transit-accessible and/or jobs-rich areas, but the evidence concerning the impacts of these laws on housing development remains largely anecdotal. In particular, policymakers lack adequate information concerning: (1) the types of neighborhoods where developers are more likely to build; and (2) the causes of delays in approvals for proposed projects in jobs-rich and transit-accessible areas. In new research, scholars from UC Irvine and UC Berkeley address this problem by drawing on a unique project-level dataset, the Comprehensive Assessment of Land Use Entitlements (CALES), to analyze development projects including five or more residential units that were approved for development from 2014 through 2017 in six cities: Inglewood, Long Beach, Los Angeles, Pasadena, Redondo Beach, and Santa Monica.
While the impact of plug-in electric vehicles (PEVs) on electricity generation and transmission has been studied extensively, the impact of PEVs on the resiliency of the local electricity distribution system has not been addressed in detail. Understanding resiliency impacts is important as the increased use of PEVs, and especially the clustering of PEVs in one area (such as a neighborhood), place additional pressures on already aging power grid infrastructure. As an example, charging a large population of PEVs during normal operations can stress system components (such as transformers) resulting in accelerated aging or even failure, which reduces resiliency of the system. On the other hand, PEVs can also increase system resiliency. When connected to the grid, PEVs are an energy resource that can provide electricity for critical services (such as community shelters) during grid outages and facilitate grid restoration by providing electricity to support the restart of transformers and other utility assets.
California’s Housing Element law requires all local governments to adequately plan to meet the state’s existing and future housing needs. The law establishes processes for determining regional housing needs and requires regional councils of governments (COGs) with allocating these housing needs to cities and counties in the form of numerical targets. Local governments must update the housing element of their general plans and adopt policies to accommodate the housing targets. The California Department of Housing and Community Development (HCD) reviews all local housing elements and determines whether the elements comply with state law.
In California, there has been a growing concern about rising housing cost burdens. Declining housing affordability, particularly in job-rich areas, can lead to lengthy commutes and pose significant challenges to achieving sustainable transportation and development patterns. It may also cause disproportionate impacts on vulnerable population groups by pushing members of these group to areas where jobs and other amenities are limited. Although no single factor can fully explain the rise of this critical issue, local growth control measures (e.g., growth moratoriums, density restrictions, and public facilities requirements) and other strict land use regulations have been criticized for constraining the housing supply and adding to jobs-housing imbalances. It is important to understand what motivates local growth control actions, as well as how these controls may affect land use, housing, and transportation.
The trucking industry serves as the backbone of the nation’s economy. In 2018, approximately 3.5 million truck drivers were delivering over 70% of all freight tonnage in the United States, generating close to $800 billion in gross revenue annually.1 While 3.5 million truck drivers represents a significant number of jobs, it is not enough to satisfy demand. The trucking industry suffers from a chronic shortage of drivers. Nearly 70,000 additional heavy-duty tractor-trailer drivers in the United States were needed at the end of 2018, according to the American Trucking Associations. And COVID-19 has brought new challenges that may amplify or dampen the driver shortage and in turn impact supply chains. For example, what if a small percentage of long-haul truck drivers became ill? Would it cripple the industry? Would it significantly delay the delivery of essential medical supplies and equipment? New research from UC Irvine explored the challenges imposed by COVID-19 on truck drivers by conducting a literature review, looking at past crises, and interviewing academic and industry experts.
Tractor-trailers dominate the truck cargo industry. Between 1990 and 2010, this industry grew significantly; vehicle miles traveled increased 87 percent and ton-miles increased by 47 percent. While the growth of trucking miles and tonmiles is a positive indicator of economic transformation and expansion, the trucking sector also produces negative externalities, including but not limited to pavement damage. Pavement damage is closely tied to vehicle weight, which is a product of private market decisions driven by the cost of delivery per ton and the frequency of delivery. Understanding the interplay between fuel cost and private sector decisions on truck dispatch (i.e., frequency and load of trucks) is key to understanding infrastructure damage.
Workers in Southern California currently face transportationrelated challenges accessing employment opportunities, including but not limited to high parking costs and/or limited parking availability in dense employment and residential areas; long commute distances between residential areas and employment opportunities; and poor transit service quality in many areas. These challenges are particularly burdensome for low-income households that may not have access to a personal vehicle and/or live in jobpoor neighborhoods, as having a personal vehicle may be the only viable way to get to work.
