Gaining Wait? Analyzing the Congestion Impacts of Road Diets in Los Angeles

Status

Complete

Project Timeline

September 1, 2017

Principal Investigator

Dylan Jouliot

Project Team

Project Summary

While numerous studies have shown road diets can greatly reduce the number and severity of collisions, especially for pedestrians and cyclists, the public response to many of the changes implemented in Los Angeles has been quite negative. Angry residents and commuters have organized protests of the roadway changes, initiated campaigns to recall city councilmembers who have supported the changes and even successfully lobbied to have road diets undone and converted back to their previous state. This negative response has largely centered on claims of large increases in congestion and travel times along the streets where the Los Angeles Department of Transportation (LADOT) has removed lanes. The Active Transportation and Special Programs (ATSP) team of the Southern California Association of Governments (SCAG), the Metropolitan Planning Organization for the Southern California region, has a strong interest in improving traffic safety in the region, and seeks research to determine if these proven safety improvement measures cause the delays and increases in congestion that opponents claim. To examine this issue the graduate student researcher surveyed existing literature on road diets and their congestion impacts, analyzed before and after LADOT daily traffic volume data for a number of street segments where the city installed road diets and nearby parallel segments where no change was made, and observed current conditions of ten intersections within the selected street segments to assess potential ongoing delay and congestion in the study corridors. The analysis finds an overall increase in traffic volumes on the selected road diet corridors of 8 percent, while volumes decreased very slightly on nearby parallel corridors. While the limitations of using daily traffic volume data to estimate congestion mean that these results do not disprove the possibility of increased congestion after road diet installations, the fact that more vehicles passed through road diet corridors without corresponding increases in volumes on nearby streets suggests that drivers did not divert to nearby streets as might be expected with increases in congestion and delay. Field observations of representative intersections for each of the four road diet corridors and their respective control corridors suggest that current lane configurations have not negatively affected peak-hour traffic flow or level of service on either the road diet or control corridor.

Travel Behavior Impacts of Transportation Demand Management Policies: May is Bike Month in Sacramento, California

Status

Complete

Project Timeline

July 1, 2018 - September 30, 2019

Principal Investigator

Project Team

Jai Malik, Farzad Alemi

Project Summary

Active modes of transportation like bicycling and walking are extremely beneficial to society. Encouraging more people to bike and walk helps reduce the amount of travel people may make by car (i.e., vehicle miles travelled) and in turn helps to reduce congestion and transportation-related greenhouse gas emissions and air pollutants. Bicycling and walking also have direct and positive health impacts. A number of steps have been taken to promote active transportation in cities and regions, including awareness campaigns, transportation demand management (TDM) policies, building new bicycling infrastructure, and the launch of bikesharing programs. However, it is often unclear how much impact a specific strategy can have on actual rates of bicycling and walking in a community or region. UC Davis is assisting the Sacramento Council of Governments (SACOG) in evaluating the impact of the agency’s ‘May is Bike Month’ campaign. The purpose of the campaign is to motivate residents working and/or living in the region to start using (or increase use of) bicycles as a mode of transportation. SACOG conducted a survey as part of the 2018 “May is Bike Month” campaign, which collected self-reported information from participants on the frequency of bicycling before and after the campaign, perceived barriers to bicycling, motivations for bicycling, travel habits, household and individual sociodemographic, place of residence of the participants. UC Davis is analyzing the survey data to gain a better understanding of the role land use characteristics and transit accessibility have on bicycling rates. This information will be used to understand the variables that affect individuals’ decisions to increase, decrease or not change the level of bicycling during and after the end of the ‘May is Bike Month’ campaign. This project helps SACOG identify the groups which are most and least receptive to the campaign, and ways these groups of individuals have reacted (in terms of changing their bicycling behavior) in response to the campaign. SACOG can use this information to make strategic changes to its annual “May is Bike Month” campaign in order to optimize the campaign’s effectiveness in future years, and/or coordinate the campaign with additional initiatives to promote bicycling in the Sacramento region.

Develop plan to measure performance of broader TDM program (SACOG TDM match)

Status

Complete

Project Timeline

July 1, 2018 - September 30, 2019

Principal Investigator

Mollie Cohen D'Agostino

Campus(es)

UC Davis

Project Summary

[No abstract found on website]

Transportation Plans: Their Informational Content and Use Patterns in Southern California

Status

Complete

Project Timeline

January 1, 2018 - December 31, 2018

Principal Investigator

Campus(es)

UC Irvine

Project Summary

Since 1937, “all cities and counties [have been] required to adopt master plans [called ‘general plans’ nowadays] … [and, in 1955] land use and circulation elements [became] required in the general plan” (California Governor’s Office of Planning and Research, 2003). Recently, as the California Complete Streets Act (AB 1358) is implemented, “all cities and counties, upon the next update of their circulation element, must plan for the development of multimodal transportation networks.” Other state legislation (e.g., SB 375) has placed emphasis on internal consistency (e.g., consistency of a locality’s circulation element with other general plan elements or policies it has adopted) and cooperation among jurisdictions to achieve regional Greenhouse Gas (GHG) emission reduction targets and other goals set included in the Sustainable Communities Strategy (SCS) and Regional Transportation Plan (RTP). However, despite the state-level guidelines and requirements, general plan making rests with individual localities, and the content/structure of plans does vary markedly across cities. Little is known about the informational contents of these plans and their use patterns. This project reviewed the content of eight recently adopted general plans in Orange County and conducted a plan use survey and follow-up analysis of survey responses. All plans analyzed were found to convey a variety of information about their visions, goals, policies, and implementation strategies, but the plan content analysis revealed substantial variation in the way cities composed their general plans and integrated them with other plans/players. Compared to land use elements, circulation elements tended to focus more on their connections with other agencies than on internal consistency. The plan use survey yielded a low response rate which may indicate limited use of plans in the field. However, a majority of the survey responses were positive about the usefulness and usability of general plans.

Does Bundled Parking Influence Travel Behavior?

Status

Complete

Project Timeline

September 1, 2017

Principal Investigator

Miriam Pinski

Project Team

Campus(es)

UCLA

Project Summary

Parking requirements hide the cost of storing a vehicle in housing costs, making driving a more attractive option for vehicle owners than using alternative modes of transportation.This study uses data from the 2013 American Housing Survey to determine if the presence of bundled parking is associated with a household’s transportation mode choice. After controlling for differences in socioeconomic and built environment characteristics, the presence of bundled parking is found to be associated with a 27 percent increase in vehicle miles traveled. Bundled households drive approximately 3,800 miles more, spend nearly $580 more on gasoline, and emit 14.47 more metric tons of carbon dioxide per year. Bundled parking is also negatively correlated to transit use, and households with unbundled parking are significantly more likely to be frequent transit users. This provides further evidence for the already strong case against parking requirements.

Efficient Mobility Portfolio Schemes for Integrated, Intermodal, and Incentivized Shared Transportation

Status

In Progress

Project Timeline

January 1, 2018 - December 31, 2018

Principal Investigator

Project Summary

Flexible transportation options such as ridesharing, carsharing, and bikesharing can be effective feeders for public transportation service because these new options have higher accessibility to travelers’ origin and destination. The private sector that now plays an increasing role as a component of urban transportation can augment public transportation accessibility. In other words, Transportation Network Companies (TNCs) and Mobility Service Providers (MSPs) can be complementary modes to transit system by providing shared use of transportation capacity. This option requires a matching algorithm between drivers and riders. Implementing a comprehensive multi-modal multiple-option shared travel system in an urban area is required to improve efficiency of transportation systems. This integrated platform can identify various travel options and recommends travelers with tailored information. Some options might have a route consisting of multiple modes (i.e.: ridesharing- transit-bikesharing). Some options might suggest a detour, compared to the shortest path what user’s primary mode has. To compensate the loss of users’ utility by giving up their primary mode and to encourage use of alternative mode option, the optimal incentive scheme will be proposed. This proposal is to study the benefits of a smart mobility portfolio which is a trip planning system integrating multiple travel modes and including an incentive scheme. A smart mobility portfolio can provide time-dependent trip plans across multiple modes that include several options such as shared-cars, shared-rides, bikesharing, bus/rail transit and combinations of travel modes. Four main components of this system are: 1) to identify travel options for achieving efficiency under current traffic conditions and supply conditions, 2) to calculate proper amounts of incentive to attract people to choose one of the options, 3) to provide travelers with the best travel options among these alternatives, and 4) to examine the impact of the proposed method to entire transportation systems and to update the parameters in the model. Encouraging people to change their current travel behavior through the smart mobility portfolio platform, researchers expect the improvement of traffic network efficiencies and the contribution to eco-friendly environment by reducing traffic congestion.

Simulating Life with Personally-Owned Autonomous Vehicles through a Naturalistic Experiment with Personal Drivers

Status

Complete

Project Timeline

July 1, 2017 - December 31, 2020

Principal Investigator

Project Team

Project Summary

To date, little is known about how travel will change with self-driving vehicles. The biggest difference in using a self-driving car, and arguably the feature that will cause the most change in travel behavior, is not having to be behind the wheel driving the car or having to be in the car at all as it travels from one place to another. Existing behavioral studies exploring this unknown future are limited because they either focus on safety and human factors rather than travel behavior, assume travel behavior implications, or ask about hypothetical scenarios that are unfamiliar to the subjects. This project will explore the potential impacts of self-driving vehicle deployment on travel patterns and behavior through a naturalistic experiment. Households in the greater Sacramento area will be recruited to participate in a three-week travel study. All travel during this time will be monitored and tracked. At the beginning of the three-week period, participants will take part in a one-on-one entrance interview to receive an overview of self-driving cars and share their attitudes toward self-driving cars. During the second week, participants will have access to a professional driver for a set block of time. Having access to a driver will relieve participants from the duty of personally driving or physically being in a car when the car is making trips, while maintaining the other aspects of owning a personal vehicle (e.g. fuel and other vehicle costs). Upon completion of the three-period, participants will take part in an exit survey similar to the entrance survey in terms of (re)asking about attitudes toward self-driving cars in addition to being asked about their experience with the simulated self-driving car experience. This experiment leverages a framework that has already been beta tested providing evidence of value.

Linking Statewide and Regional Travel Models to Estimate Interregional Travel Impacts in California

Status

In Progress

Project Timeline

October 1, 2016 - June 30, 2024

Principal Investigator

Campus(es)

UC Irvine

Project Summary

Metropolitan Planning Organizations (MPOs) use regional travel forecasting models to estimate vehicle trips (VT), average speeds, and vehicle miles traveled (VMT), which serve in turn as input to regional emission models. Interregional travel is not usually part of MPO models, but it is explicitly part of statewide models. The California Statewide Travel Demand Model (CSTDM) is an activity-based model that produces statewide origin-destination trip tables for assignment to the statewide network. Consistency tests, however, suggest that there are significant deviations between link counts from the CSTDM and those from regional models, as measured at defined cordon stations. These trip counts are, by definition, interregional travel – travel that is typically generated within a region but with performance impacts in another region or in areas not formally part of a defined region.

The proposed project seeks to develop and test methods to synchronize the travel forecasting results of the CSTDM with regional travel forecasting models, with the objective of better estimating interregional travel and greenhouse gas emissions in California. Whether trip-, tour-, or activity-based, CSTDM and all current regional models apply conventional trip assignment as the last step in the modeling process. From the perspective of potential policies to address performance impacts, this study will resolve how regions and the state properly account for the relative proportion of interregional travel and the associated travel impacts. The methodological problem is to synchronize the assigned and validated cordon counts produced by regional models with those generated as part of assignment in the CSTDM. Techniques to modify origin-destination trip tables exist but applications above the local area have been rare. The CSTDM trip tables will be updated to reflect the assigned counts at defined MPO cordon stations. At least two methods will be tested using Caltrans’ Performance Measurement System (PeMS) data with CSTDM trip tables and using MPO cordon estimates with CSTDM trips tables. Each method will be evaluated, with one selected for final application based on its consistency across all model levels and data sources.

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

Grocery Shopping in California and COVID-19: Transportation, Environmental Justice, and Policy Implications

Abstract

The COVID-19 pandemic upended many aspects of our lives, including how we shop for groceries. As grocery stores scaled back their opening hours and managed access, many shoppers switched to online shopping with home delivery (“e-grocery”) or store pick-up (“click-and-pick”). Few empirical studies published to date have explored how the COVID-19 pandemic changed grocery shopping, the extent to which these changes may last, how the pandemic exacerbated grocery store access inequalities, and how access to groceries in California is intertwined with environmental justice concerns. Moreover, most studies on this topic were based on non-random samples, which can provide quick results in a fast-changing environment but their findings are not generalizable.

This brief explores the effects of changing grocery shopping trends on disadvantaged communities in California. Using data obtained by surveying California members of KnowledgePanel,® the largest and oldest online probability-based panel representative of the U.S. population, the research team explored the frequency of grocery shopping in California and likelihood of it changing after the pandemic; the types of stores Californians shopped in for groceries during the pandemic and who used grocery delivery companies; and how / if environmental justice factors played a role in observed changes in grocery shopping.