The driving habits of US millennials (roughly defined as persons born between 1980-2000, with a current estimated population of 75 million) has been identified as having a dampening effect on automobile ownership and passenger vehicle miles travelled (VMT).  There is little available information or research to enable a quantification of this effect, and its potential magnitude in future decades.  Metropolitan Planning Organizations (MPO) need more information to be able to model or otherwise estimate the impact of this effect on regional VMT and greenhouse gas (GHG) emissions, for purposes of their Sustainable Communities Strategies (SCS) under SB 375.
This research will investigate the magnitude of potential GHG and VMT benefits from millennial driving behavior and develop data and information that MPOs can use to estimate the regional GHG and VMT benefits of this demographic shift for purposes of meeting SB 375 targets. The research will involve 4 tasks:  
1. A review of existing research and available data sources on the effects of millennial driving behavior on VMT; 
2. A discussion of the possible causes of millennial driving behavior and how the built environment may affect this behavior;
3. An estimate of the magnitude of the effect of millennial driving behavior on VMT and GHG emissions; 
4. An identification of the kinds of regional policy interventions or SCS strategies that would be effective in encouraging a continuation of this behavior even as millennials age.

GPS-based activity and travel diary surveys have been increasingly used to assess whether transportation and sustainability strategies for compact, mixed-use, and transit accessible communities result in reduced vehicle travel, reduced greenhouse gas emissions, greater opportunities for physical activity, and enhanced accessibility. For instance, the Southern California’s long range plan indicates over 50% of new jobs and housing will be located in high-quality transit corridors, and the Los Angeles Metropolitan Transportation Authority (LA Metro) is currently aggressively expanding its rail transit network, but few studies have examined the impacts of such investments on travel and spatial activity patterns.
This study provides insights into the impact of rail transit investments and compact development policies. This component examines California Household Travel Survey (CHTS) data to examine whether more compact, mixed-use and transit accessible areas are associated with greater gender equality in the geographic extent of activity-travel patterns given previous research that suggests compact design may help reduce gender differences in the division of household tasks including errands and “chauffeuring travel”.  

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.

Many of the biggest transportation challenges in Southern California arise from the lack of concentration of densities. However, little is known about how to address this critical problem and its adverse consequences. While recent years have witnessed increasing efforts to expand public transit services and encourage compact development in transit areas, there is a dearth of research providing detailed guidance for improving the distribution of densities in the region. Furthermore, existing studies have tended to focus on the City of Los Angeles, resulting in lost opportunities for understanding what challenges exist in the rest of the region, particularly in (suburban) places with great potential for density concentrations. This project will examine the complexity of urban densification dynamics with a focus on thirty selected cities in Southern California where public transit services will be widely available and thus land use intensification will be highly desired in the future. Specifically, the project will (i) conduct an exploratory analysis to identify ways in which urban densification takes place through zoning and actual land use changes that should be jointly addressed in coordination with transportation planning; (ii) develop a model to better understand how zoning has changed (in relation to the expansion of public transit services), to what extent zoning changes have led to shifts in actual land use patterns, and how changes in land use induce further zoning modifications in nearby areas; and (iii) identify hotspots that deserve attention for more strategic densification in the region.

California’s Housing Element law requires the allocation of housing targets to local governments. These targets should align with long-range regional strategies to concentrate growth in transit rich areas, but little evidence exists about the effectiveness of housing allocation schemes for achieving accessibility and affordability. Indeed, there is some evidence that – to date – the law has not served these goals effectively. In 2018 California Senate Bill (SB) 828 significantly amended the Housing Element law, conferring additional authority on the California Department of Housing & Community Development (HCD) to determine housing targets. Moreover, SB 50 (introduced in 2019) proposes to require HCD to identify “jobs-rich” areas, in which local governments would be required to allow relatively dense residential development. SB 50 proposes to also raise the minimum allowable density for residential development in areas close to transit stops. State legislators and administrators have very little information to evaluate the current housing target allocation process or its interaction with the regulatory scheme contemplated by SB 50. This project would fill that gap, providing guidance for linking housing and transportation policy. This project will provide decision support for state legislators and administrators by: 1) comparing California’s housing target allocation and implementation methods to methods currently used in other states, as well as methods described in the scholarly literature; 2) comparing the possible effects of different allocation and implementation methods on job accessibility at different levels of housing affordability; and 3) identifying ways that future legislation and implementation could promote the goals of the Housing Element law related to accessibility.