research report

Quantifying Major Travel Delay Reduction Benefits from Shifting Air Passenger Traffic to Rail

Abstract

This study provides a method to quantify the benefits of reducing the costs from flight delays by shifting air passenger traffic to high-speed rail (HSR). The first estimate was the number of flight reductions by each quarter hour for airport origin and destination pairs based on HSR ridership forecasts in the California High-Speed Rail 2020 Business Plan. Lasso models are then applied to estimate the impact of the reduced queuing delay at SFO, LAX and SAN airports on arrival delays at national Core 29 airports. Finally, these delay reductions are monetized using aircraft operating costs per hour and the value of passenger time per hour. The research team applied several different variations of this approach, for example, considering delay at all 29 Core airports or just major California airports, different scenarios for future airport capacity and flight schedules, and different forecasts for future HSR ridership. The estimated mid-range delay cost savings are $51-88 million (2018 dollars) in 2029 and $235-392 million (2018 dollars) in 2033. The estimated savings are similar to, but slightly lower than, those based on cost estimates to upgrade airport capacity to handle passenger traffic that could be diverted to HSR.

published journal article

What factors influence the adoption and use of dockless electric bike-share? A case study from the Sacramento region

Abstract

Now that dockless electric bike-share systems have become a fixture in major cities in the U.S., it is important to understand why someone chooses to use the service. Beyond socio-demographics, factors such as mode-related attitudes, the social environment, and the availability of the service may influence both its adoption and frequency of use. This study modeled dockless electric bike-share adoption and use frequency using data collected from a household survey and a bike-share user survey from the Sacramento region. The study used integrated choice and latent variable models to understand the influence of attitudes on electric bike-share adoption and use frequency. Three latent variables − bike affinity, car necessity, and bike social environment − were developed using responses to eleven statements. The models show that apart from socio-demographics, attitudes related to bike affinity and bike social environments significantly and positively influence bike-share adoption with a large effect size, whereas the car necessity attitude significantly and negatively influences the use frequency with a large effect size. Individuals with low incomes are less likely to adopt the bike-share service. The availability of electric bike-share in key locations (home and/or work and/or school) where an individual frequently goes significantly and positively influences adoption with a large effect size but does not influence use frequency. Findings from this study can inform the dockless electric bike-share policies of cities as well as the rebalancing strategies of service providers.

policy brief

Truck Parking and Idling is Having an Impact on Disadvantaged Communities in California

Abstract

Under California Assembly Bill 617 (Garcia, 2017), local and state agencies are working to reduce air pollution exposure in low income communities. These communities—often referred to as AB 617 communities—are disproportionately impacted by air pollution due to their proximity to transportation corridors, industrial installations, and logistics centers. A research team at the University of California, Davis investigated the impact of truck parking related activities on air quality in California’s AB 617 communities in Kern County, including truck idling, time spent searching for parking, and parking locations in communities. Searching for parking involves trucks driving extra miles to find available parking spaces, which leads to additional fuel consumption and increased emissions of pollutants such as nitrogen oxides (NOx) and particulate matter (PM 2.5 and PM 10). Once parked, prolonged or illegal parking can exacerbate congestion, noise, and localized pollution. These combined activities heighten exposure to harmful emissions in EJ communities, potentially leading to health issues (e.g., asthma and cardiovascular diseases). A comprehensive policy framework addressing truck parking facilities, management, and air pollution control is crucial for improving air quality and living conditions in AB 617 communities. There are a number of initiatives that could contribute to improving the conditions on these communities.

An Analysis of Travel Characteristics of Carless Households in California

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Project Team

Suman Mitra

Campus(es)

UC Irvine

State-Level Strategies for Reducing Vehicle Miles of Travel

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Campus(es)

UC Davis

Project Summary

California has set ambitious goals for reducing its greenhouse gas emissions to 40% below 1990 levels by 2030 and 80% below 1990 levels by 2050. To meet these goals, the state must achieve a 15 percent reduction in total travel by light-duty vehicles by 2050 compared to expected levels.1,2 Under current state policies, reductions of this magnitude are unlikely. Strong evidence exists that strategies across four categories – pricing, infill development, transportation investments, and travel demand management programs – can reduce vehicle miles of travel (VMT).3 The state can directly implement some of these strategies, particularly pricing strategies, through state-level policies. Others depend on actions by regional and local governments, though state-level policies can encourage their implementation through incentives, requirements, or other mechanisms.

Do Compact, Accessible, and Walkable Communities Promote Gender Equality?

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Policy and Literature Review on the Effect Millennials Have on Vehicle Miles Traveled, Greenhouse Gas Emissions, and the Built Environment

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Project Team

Michelle E. Zuniga

Campus(es)

UC Irvine

Clean Air in Cities: Impact of the Layout of Buildings in Urban Areas on Pedestrian Exposure to Ultrafine Particles from Traffic

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Project Team

Liye Zhu, Dilhara Ranasinghe, Marcelo Chamecki, Michael J. Brown

Project Summary

Southern California is no stranger to auto-related pollution. Areas near roadways typically demonstrate much higher pollutant concentrations; as a result, pedestrians and residents in these areas face greater exposure to air pollutants. In dense urban areas like Los Angeles, near-roadway environments can include most street-level outdoor spaces. At the same time, traffic-related pollution levels in urban areas are highly variable. Although the connection between built environment and street-level pollutant concentrations is a nascent field of study, it is clear that the design of the built environment plays a major role on pollution concentration.

The researchers examined the effects of different built environment designs on the concentrations of street-level ultrafine particles (UFP) at the scale of several blocks using the Quick Urban and Industrial Complex (QUIC) numerical modeling system. They evaluated the effects of several built environment designs, changing building heights and spacing while holding total built environment volumes constant. They found that ground-level open space reduces street-level pollutant concentrations. Holding volume/surface area constant, tall buildings clustered together with larger open spaces between buildings resulted in substantially lower pollutant concentrations than buildings in rows. Buildings arranged on a ‘checkerboard’ grid with smaller contiguous open spaces, a configuration with some open space on one of the sides of the roadway at all locations, resulted in the lowest average concentrations for almost all wind directions. Rows usually prohibit mixing for perpendicular and oblique wind directions, even when there are large spaces between them, and clustered buildings have some areas where buildings border both sides of the roadways, inhibiting mixing. The model results suggest that pollutant concentrations drop off rapidly with height in the first 10 m or so above the roadways. In addition, the simulated vertical concentration profiles show a moderate elevated peak at the roof levels of the shorter buildings within the area. Model limitations and suggestions both for urban design are both discussed.

Transit Investment Impacts on Land Use Beyond the Half-Mile Mark

Status

Complete

Project Timeline

August 1, 2016 - July 31, 2017

Principal Investigator

Project Team

Ashley (Wan-Tzu) Lo, Jaewoo Cho

policy brief

Examining Both Trip Level Mode Replacements and Daily Activity Patterns of Users is Required to Understand the Sustainability Potential of Micromobility

Abstract

Micromobility options such as electric bike-share and scooter-share services are a fundamental part of the existing shared mobility landscape. Research has shown that micromobility use can reduce car dependence. This is accomplished through trip-level mode replacement and adjustments in mode-use configurations in daily travel. Understanding the full potential of micromobility services as a car replacement can help cities better plan for the services to meet environmental sustainability goals. Researchers at the University of California, Davis collected GPS-based travel diary data from individual micromobility users from 48 cities in the US and examined their travel behavior and micromobility use patterns. They found that micromobility services can displace car use. To achieve environmental sustainability goals, cities must pursue options that will deliver benefits, such as micromobility services. This policy brief summarizes the findings from that research and provides policy implications.