published journal article

Using a Modified Delphi Approach to Explore California's Possible Transportation and Land Use Futures

Abstract

Many methods exist for engaging experts in interactive groups to explore, clarify, and/or decide on various issues. In an investigation of four possible future scenarios concerning transportation and land use in California, researchers at UCLA developed a novel “hybrid policy Delphi” method for use with a panel of 18 experts. Through this process, panel members discussed and reflected on the scenarios in multiple ways. The scenario they considered most desirable they also deemed least likely to occur, and they foresaw the likely trajectory of California transportation and land use leading to less desirable scenarios. The mix of discussion and questionnaires traded the benefit of anonymity for the benefit of exploratory, interactive discussion. In addition, the use of surveys before and after meetings allowed the research team to track changes in panel opinion on a central question and discuss the survey results at meetings, at the cost of greater administrative effort.

research report

Evaluating Transportation Equity Data Dashboards

Publication Date

September 1, 2024

Author(s)

Jesus M. Barajas, Claire McGinnis

Abstract

The historical impacts of transportation planning and investment have left lasting scars on communities of color and low-income communities. This report evaluates online equity tools that exist as spatial dashboards —i.e., interactive maps in which the parameters of interaction are controlled. Twelve tools ranging from the national to the local level were identified and qualitatively assessed for their ability to address conditions related to transportation equity. The evaluation focused on how each tool defines disadvantaged communities, the outcomes they measure (benefits, burdens, or other), their ease of use, and their ability to guide decisions about equity. The findings show a diversity of methods and metrics in defining disadvantage, with most relying on composite demographic indexes and comparative population thresholds. Tools most commonly provided accessibility metrics to assess transportation benefits, while incorporating a range of environmental and health indicators as burden measures. A minority of tools had integrated features to support planning or project implementation.

policy brief

Multifamily Households Across California are Paying A lot More to Charge their Electric Vehicle

Abstract

Most residents of multifamily housing (MFH) and urban homes with only street parking (i.e., no garage or private driveway) do not have access to home electric vehicle (EV) charging. These residents rely primarily on public direct current fast charging (DCFC) stations where the price of electricity is not regulated and in turn more expensive compared to what a single-family household would pay.

This policy brief highlights findings from research that compared charging costs at public EV DCFC stations to the cost for single-family housing (SFH) residents charging at home for three California electric utility service areas and for three urban areas – Sacramento, San Diego, and San Jose. The research used a combination of observed pricing data from PlugShare, a crowd-sourced database of public EV charging, and public DCFC pricing data from electric vehicle service provider (EVSP) websites, as well as electric utility tariff information from their respective websites.

published journal article

To Pool or Not to Pool? Understanding Opportunities, Challenges, and Equity Considerations to Expand the Market for Pooling?

Abstract

On-demand mobility services like bikesharing, scooter sharing, and transportation network companies (TNCs) are transforming travel by providing flexible, on-demand options that complement public transit and personal vehicles. Their rapid adoption, particularly in urban areas, is driven by affordability and convenience. The growth of ridesharing and TNCs offers an opportunity to reduce congestion, energy use, and emissions by encouraging pooled rides and reducing personal vehicle ownership. This research uses a survey of four California metropolitan regions to explore policy strategies that incentivize pooling. It highlights how frequent TNC users, particularly low-income individuals, rely on these services for essential trips and are more likely to consider pooling. Time and cost tradeoffs are also examined across different regions and demographics to inform policies aimed at increasing pooling through pricing, curb management, and promotional efforts.

policy brief

Are Dynamic Wireless Charging Lanes for Electric Drayage Trucks a Viable Option for California?

Abstract

State regulations require all drayage trucks transporting containers and bulk goods to and from seaports and intermodal railyards to be zero-emission by 2035, and starting in 2024 trucks registered with the California Air Resources Board must be zero-emission. Converting these trucks to electric power is a promising pathway, and Dynamic Wireless Charging Lanes (DWCLs) could serve as a powerful supplement to traditional stationary charging stations.

This policy brief highlights findings from research exploring DWCL applications in California. The research developed a hypothetical case study of DWCL deployment for drayage trucks on a highway network of more than 1,000 miles around the Greater Los Angeles area, including the Port of Los Angeles and the Port of Long Beach. The research identified optimal locations for DWCLs to serve drayage trucks efficiently along with consideration of suitable grid connections and upgrades of the existing power grid to meet heightened energy demand.

policy brief

A New Approach to Calculating Dynamic Pricing of High-Occupancy-Toll (HOT) Lanes Can Improve the Performance of Travel Corridors

Abstract

As traffic congestion continues to worsen in urban areas, policymakers are seeking innovative solutions to maximize existing road infrastructure and improve travel times. High-occupancy-toll (HOT) lanes offer a promising solution by allowing single-occupancy vehicles (SOVs) to use underutilized carpool lanes for a fee, reducing congestion in regular lanes. Current pricing methods often struggle to set the right toll in real-time, leading to HOT lanes that are either underused or too congested. This reduces their effectiveness in managing traffic and can frustrate drivers. To address this issue, UC Irvine researchers developed more effective ways to set HOT lane prices in real-time, ensuring they are used efficiently and provide reliable travel times for all drivers. Improving HOT lane operation can lead to reduced congestion, shorter commute times, and more efficient use of existing road infrastructure – all without the need for costly new road construction.

published journal article

A Control Theoretic Approach to Simultaneously Estimate Average Value of Time and Determine Dynamic Price for High-Occupancy Toll Lanes

Abstract

The dynamic pricing problem of a freeway corridor with high-occupancy toll (HOT) lanes was formulated and solved based on a point queue abstraction of the traffic system. However, existing pricing strategies cannot guarantee that the closed-loop system converges to the optimal state, in which the HOT lanes’ capacity is fully utilized but there is no queue on the HOT lanes, and a well-behaved estimation and control method is quite challenging and still elusive.

This article attempts to fill the gap by making three fundamental contributions: (i) to present a simpler formulation of the point queue model based on the new concept of residual capacity, (ii) to propose a simple feedback control theoretic approach to estimate the average value of time and calculate the dynamic price, and (iii) to analytically and numerically prove that the closed-loop system is stable and guaranteed to converge to the optimal state, in either Gaussian or exponential manners.

published journal article

Stable Dynamic Pricing Scheme Independent of Lane-choice Models for High-Occupancy Toll Lanes

Abstract

There are two operational objectives for operating high-occupancy toll (HOT) lanes: (i) to maintain the free-flow condition to guarantee the travel time reliability; and (ii) to maximize the HOT lanes’ throughput to minimize the system’s total delay. The traffic dynamics on both HOT and general purpose (GP) lanes are described by point queue models, where the queueing times are determined by the demands and capacities.

This article considers three types of lane-choice models: the multinomial logit model when single-occupancy vehicles (SOVs) share the same value of time, the vehicle-based user equilibrium model when SOVs’ values of time are heterogeneous and follow a distribution, and a general lane-choice model. The article demonstrates that the second objective is approximately equivalent to the social welfare optimization principle for the logit model. Observing that the dynamic price and the excess queueing time on the general purpose lanes are linearly correlated in all the lane-choice models, the article proposes a feedback control method to determine the dynamic prices based on two integral controllers. The article further presents a method to estimate the parameters of a lane-choice model once its type is known. Analytically the article proves that the equilibrium state of the closed-loop system with constant demand patterns is ideal, since the two objectives are achieved in it, and that it is asymptotically stable. With numerical examples, the article verifies the effectiveness of the solution method.

policy brief

An L.A. Story: The Impact of Housing Costs on Commuting

Abstract

Concerns about the environmental impacts of transportation have made reducing vehicle miles traveled (VMT) a policy priority. One way to decrease VMT is to decrease the length of commuting trips, and to get commuters out of their private vehicles. Although many studies have investigated the determinants of commuting, few have analyzed the linkage between housing costs and commuting.

To address this gap, researchers at UC Irvine developed a model that jointly explains commuting time and distance, and accounts for residential self-selection (i.e., where someone chooses to live), the effect of car ownership, and key land use characteristics around both residences and workplaces. The research focused on Los Angeles County. Census data shows that the average commute time for Los Angeles County residents pre-pandemic was 32.8 minutes, 18.8 percent higher than the national average.

policy brief

Did Extending Driver Licenses to Individuals Without Legal Presence Affect Transit Ridership in Orange County?

Abstract

Between 2014 and 2017, transit ridership in the U.S. declined by 6%, while bus transit ridership fell by 9.5%. Some regional agencies such as the Orange County Transportation Authority (OCTA) were particularly affected. Changing socioeconomic conditions, service quality, and increased competition from transportation network companies (e.g., Uber, Lyft) are some of the reasons behind the observed decline in bus ridership. The implementation of The Safe and Responsible Drivers Act of 2013 (Assembly Bill 60) may have also impacted ridership, which directs the California Department of Motor Vehicles to issue a driver’s license to applicants who are unable to provide proof of legal presence in the United States but can provide satisfactory proof of identity as well as California residency. Some of these individuals could have been relying on transit since they could not legally obtain a driver’s license.

UC Irvine researchers examined if observed line-level changes in OCTA bus boardings could be partly attributed to AB 60, while controlling for differences in transit supply, socioeconomic variables, gas prices, and the built environment. Using fixed effects panel data models, the team analyzed monthly boardings on different OCTA route classifications—local, community, Express, and station link routes—one year before (2014) and two years after (2015 and 2016) AB 60’s implementation.