Local Climate Action Planning as a Tool to Harness Greenhouse Gas Emissions Mitigation and the Equity Potential of Autonomous Vehicles and On-Demand Mobility

This paper focuses on how cities can use climate action plans (CAPs) to ensure that on-demand mobility and autonomous vehicles (AVs) help reduce, rather than increase, greenhouse gas (GHG) emissions and inequitable impacts from the transportation system. We employed a three-pronged research strategy involving: (1) an analysis of the current literature on on-demand mobility and AVs; (2) a systematic content analysis of 23 CAPs and general plans (GPs) developed by municipalities in California; and (3) a comparison of findings from the literature and content analysis of plans to identify opportunities for GHG emissions reduction and mobility equity. Findings indicate that policy and planning discussions should consider the synergies between AVs and on-demand mobility as two closely related emerging mobility trends, as well as the key factors (e.g., vehicle electrification, fuel efficiency, use and ownership, access, and distribution, etc.) that determine whether the deployment of AVs would help reduce GHG emissions from transportation. Additionally, AVs and on-demand mobility have the potential to contribute to a more equitable transportation system by improving independence and quality of life for individuals with disabilities and the elderly, enhancing access to transit, and helping alleviate the geographic gap in public transportation services. Although many municipal CAPs and GPs in California have adopted several strategies and programs relevant to AVs and on-demand mobility, several untapped opportunities exist to harness the GHG emissions reduction and social benefits potential of AVs and on-demand mobility.

wellbeing. Technological advances in AVs and ODM can enhance the transportation emissions reduction potential of CAPs and simultaneously contribute to social equity and quality of life. As such, this paper opens a dialogue between local governments, AV and ODM companies, and users of these technologies that can lead to better social and environmental outcomes.
A three-pronged research strategy was employed to answer the research question: (1) an analysis of the current literature on ODM and AVs; (2) a systematic content analysis of 23 CAPs and general plans (GPs) developed by municipalities in California; and (3) a cross-comparison of findings from the literature and content analysis of plans to identify opportunities for GHG emissions reduction and mobility equity through the adoption of ODM and AVs.

Potential Environmental and Social Impacts from Autonomous Vehicles and On-Demand Mobility
Two emerging trends in mobility-AVs and ODM (which includes ridesharing or ridehailing)-have the potential to affect travel behavior dramatically and, by extension, the environmental and social impacts of transportation. Both trends have many potential or claimed benefits from the vehicle, the network they are connected to, and the users. These benefits include better road usage; increased safety for pedestrians and passengers; reduced traffic; increased road capacity; enhanced access to jobs, services, and amenities for low-mobility individuals; reduced parking needs; improved equity; and energy conservation and reductions in emissions and fuel use (1)(2)(3)(4)(5)(6)(7). Nevertheless, adopting these technologies also carries risks; under certain scenarios, they might exacerbate, rather than relieve, the negative externalities associated with current vehicle use. Some researchers predict that AVs and ODM will increase VMT (8), raise transportation costs, and diminish support for public transit (5). Additionally, it has been argued that there are other potential trade-offs, where GHG emissions from AV production are expected to be higher than from the production of internal combustion vehicles, but their lifecycle costs have a lower net GHG cost to the environment (8). Thus, to maximize the benefits and minimize the risks, these technological developments should be accompanied by a holistic vision of vehicle lifecycles (8), greater interoperability among transportation services, and stronger policy support for shared and low-carbon mobility (9)(10)(11).
Recent literature emphasizes the potential energy and GHG impacts of vehicle automation and technologyenabled ODM and offers detailed scenario analysis to estimate such impacts. For example, researchers have estimated that AVs can result in up to 80% reductions in energy use and up to 94% reductions in CO 2 through various mechanisms such as platooning technologies, more efficient routing, more eco-friendly acceleration and braking, vehicle design, alternative fuel use, more efficient traffic flow, reduced parking needs, light-weight or efficient vehicles, and real-time or dynamic ridesharing (12)(13)(14). ODM has already shown its potential to reduce GHG emissions. Empirical studies have shown traditional taxis to have emissions up to 1.4 times higher than ODM (15). However, these emission reductions are not assured, and outcomes depend on how automation and ODM might affect travel behavior, vehicle operations, vehicle design, or the entire transportation system. Ironically, VMT and fuel consumption might significantly increase if the energy intensity benefits of AVs are not realized (6). Also, people may choose to live further from the city center when they can convert their commuting time to productive time, potentially increasing VMT and GHG emissions. Therefore, it is critical to seize these technologies' energy and emissions mitigation opportunities and minimize the risk of counterproductive outcomes through long-range policies and plans that offer a comprehensive vision of future mobility.

The Key Role for Climate Action Plans
CAPs are strategic documents that propose a comprehensive agenda to reduce GHG emissions and help communities adapt to the adverse impacts of climate change. The main question that these plans focus on is how cities can thrive in an environmentally and socially responsible way in a world threatened by climate change. CAPs typically include a list of strategies to mitigate GHG emissions from various sources: transportation and land-use; energy supply; energy demand in residential, commercial, and industrial buildings; agriculture; forestry; and waste. For example, constructing new and improved bicycle paths is a common strategy to reduce emissions from the transportation sector. CAPs may also offer several adaptation strategies that are designed to boost the ability of communities to withstand and recover from adverse climate impacts.
Local CAPs are in an ideal position to help unlock the environmental and mobility equity promises of AVs and ODM. CAPs can incorporate strategies to ensure that the GHG emissions reduction potential of AVs and ODM are realized. Also, understanding the extent to which the benefits of AVs and ODM align with CAP goals can help cities develop a better response to climate change while achieving other co-benefits, such as better connectivity, improved mobility for all, and walkability. Additionally, local CAPs increasingly focus on enhancing social equity locally while also contributing to global climate justice through the mitigation of GHGs (16). As such, the potential mobility equity benefits of AVs and ODM are highly relevant to CAP goals.
Of the four basic approaches to reducing transportation GHGs-vehicle technology, fuel technology, vehicle and systems operations, and travel activity-local CAPs have mostly focused on the latter two, since the first two are heavily influenced by federal and state policy and funding (17)(18). However, recent advances in vehicle technology, automation in particular, can dramatically affect travel activity. This makes vehicle technology strategies much more relevant to local CAPs. Because these technologies are relatively new and progressing rapidly, we anticipated that most local CAPs would fall behind in incorporating AVs and ODM. Thus, this research helps identify untapped opportunities in our current generation of local CAPs which can be used for future updates of these plans.
Despite the significance of incorporating potential impacts of AVs and ODM in CAPs, it is unclear how these plans might benefit from such emissions reduction impacts. A review of long-range transportation plans revealed that uncertainties involved in these new technologies and their impacts on investment decisions have resulted in an elimination of AV discussions in virtually all long-range transportation plans (19). On the other hand, to meet California's long-term GHG emissions reduction goal (i.e., 80% below 1990 levels by 2050), it is crucial to combine technological advances and policy packages to mitigate emissions from transportation-the largest source of overall GHGs. This research addresses this gap in the literature by identifying ways to incorporate potential impacts of AVs and ODM into local CAPs.

Concepts of Autonomous Vehicles and On-Demand Mobility
During the analysis of the literature, the research team identified 12 terms regularly used to describe specific types of AV services and ODM. These terms were used as keywords to search for relevant literature as well as to guide the content analysis of CAPs and GPs. Some of the terms explained below are directly related to AVs and app-enabled ODM, such as shared autonomous vehicles (SAVs); others are broader, such as car-sharing. These 12 terms were later used to identify categories in CAPs and GPs that were appropriate for adding measures to improve the environmental and equity benefits of AVs and ODM. For example, programs to encourage car-sharing can be used to boost the desirability and popularity of SAVs. The 12 terms on the concepts of AVs and ODM include: TNCs are companies like Uber and Lyft that use an online application to provide an arranged transportation service for a fee by connecting passengers with drivers or car owners. Unlike a taxi service that can be hailed on a street without the use of a mobile app, passengers that wish to order a ride offered by a TNC need access to the online application. 6) Ridehailing (also called ride-sourcing or e-hailing): Ridehailing services, like the services offered by TNCs, are not the same as traditional carpooling/ridesharing. Ridehailing services are often used by individual riders or by groups of people that were already traveling together. 7) Car-sharing: Car-sharing is an automobilerental service where people rent cars often for short periods of time. The most popular carsharing service in the United States is ZipCar, though other firms, including car rental giants such as Hertz and Enterprise, also offer carsharing services in select cities. Car-sharing services also provide in-neighborhood car rentals. These services, Zipcar and Getaround being two examples, allow users to pick up the vehicles nearby and drop them at the same or a different location without going to a rental counter.

8) Mobility on Demand/On-Demand Mobility:
The term mobility on demand is a broader term to describe several new innovative ways in which people use transportation today. This term is multi-modal in nature and may include a vehicle, bicycle, scooter, or any other transportation mode on an as-needed basis. Lyft, for example, now allows users to reserve bikes or scooters, as well as to book a ridehailing trip, all from the same online platform or app. 9) Ridesharing: Ridesharing includes the more traditional forms of sharing rides, such as carpooling or vanpooling. Ridesharing is meant to increase vehicle occupancy by allowing additional passengers to join an existing trip. 10) Carpooling: Carpooling is defined as prearranged groups of people going from similar origins through similar routes or to similar destinations. 11) Vanpooling: Vanpooling is described as a group of five or more people sharing their commute in a van. The van typically takes people from a prearranged meeting place to various destinations. 12) Microtransit: Microtransit refers to privately or publicly operated multi-passenger transportation services, such as Bridj, Split, and Via, that use fixed or dynamically generated routes and typically expect riders to get to pick-up or dropoff locations on their own. Microtransit vehicles can be larger SUVs, vans, or shuttle buses.

Key Findings from the Literature
An analysis of the literature reveals two critical considerations: 1) Several factors determine whether or not, and the extent to which, deployment of AVs would help reduce GHG emissions from transportation. Three major types of factor play a role in the potential GHG emissions impact of AVs: (i) factors related to the technology, functionality, and efficiency of AVs (e.g., vehicle electrification, fuel efficiency, size, connectedness, etc.); (ii) factors related to the use and ownership of AVs (e.g., shared versus single occupant; publicly owned versus privately owned vehicles); and (iii) factors related to access, distribution, and convenience of use of AVs across geography and for various population groups (e.g., wide or limited distribution of AVs in urban and suburban areas). Given the uncertainties involved in how these factors will vary in the future, projections for the GHG emissions impact of AVs involve a wide range of possible outcomes. The most optimistic projections can promise an 80% or even more significant reduction in GHG emissions, whereas the most conservative estimates predict a significant increase in GHG emissions as a result of increased VMT and unmet energy efficiency goals. 2) AVs and ODM can potentially contribute to a more equitable transportation system. Findings from the literature suggest that AVs and ODM can build a more equitable transportation system both directly and indirectly. These technologies can directly improve independence and quality of life for individuals with disabilities and the elderly, enhance access to transit by offering a viable solution for the first-and last-mile problem, and help alleviate the geographic gap in public transportation services. For indirect impacts, wide adoption of SAVs can reduce demand for parking and create an opportunity for in-fill development and affordable housing, especially in urban areas that offer better access to jobs, amenities, and services, including transportation options.

The Plan Analysis Methods
The second key study method was a content analysis of the CAPs and GPs produced by 23 California cities known to be at the forefront of climate planning.

Climate Action Plans and General Plans
We chose to analyze both municipal CAPs and GPs for each city in the data set because the two types of plan typically work together to guide a city's vision and future development goals, it is essential to look at both documents to fully understand whether a city explicitly plans for AVs and ODM as tools to reduce GHG emissions. For example, a city's GP might refer to strategies offered in the CAP to further justify an action or vice versa. To capture all relevant information, we analyzed the most recently adopted version of both types of plan.

Case Study Selection
We chose to analyze cities that are well-known for being in the vanguard of climate planning. Studying these early actors in climate planning allowed us to focus on communities that are most likely to have thought through and experienced the challenges of reducing transportation emissions significantly. Thus, these cities are particularly likely to have searched for new and innovative ways of successfully tackling GHGs from transportation.
The 23 case study cities analyzed were identified using a publicly available data set produced by ICLEI-Local Governments for Sustainability, a global network of local governments dedicated to sustainability and climate action. ICLEI offers a systematic framework for climate action planning organized around five major milestones, ranging from preparing a GHG emissions inventory to plan implementation, monitoring, and evaluation (20). From this data set, we selected the 23 municipalities that in 2009 had reached at least the third ICLEI milestone, developing a CAP.

The Plan Analysis Process
We used a four-step process to analyze the CAPs and GPs.
Phase I: We developed a spreadsheet to capture specific information about strategies to reduce transportation emissions relevant to AVs and ODM along with general information such as GHG emissions targets and baseline emissions levels. To create this spreadsheet, we drew on a review of the literature, and the 12 concepts described in the literature review section. Phase II: We coded the CAPs and GPs using the spreadsheet developed in Phase I. We used the most recent version of CAPs available at the time of this research. Phase III: We coded content pulled in the second phase to identify transportation demand management (TDM) strategies as well as transportation infrastructure measures that were relevant to shared and ODM, ridehailing, and AVs. Phase IV: We compared findings from the content analysis of plans with findings from the literature to identify untapped opportunities and possible risks of AVs and ODM.

Findings from the Climate Action Plan Analysis
This section discusses key findings from the analysis of CAPs. We looked at patterns of how many AV or ODM measures appear in CAPs, trends over time, and patterns of how frequently different types of AV or ODM measures appear in the CAPs (Table 1).

Autonomous Vehicles or On-Demand Mobility Measures have not been Fully Integrated into Climate Action Plans to Achieve Climate and Equity Objectives
One clear finding was that few cities were comprehensively planning to integrate AVs and ODM as tools to achieve climate and equity objectives. About one-third of the cities did not include a single policy option related to ODM or AVs. Moreover, among the two-thirds of CAPs that did include relevant policy measures, few incorporated more than a handful of measures. Nine incorporated two or three measures, six had four or five measures, and only one plan had seven measures.

Recently Updated Climate Action Plans Incorporated More Autonomous Vehicles and On-Demand Mobility Measures
Unsurprisingly, the CAPs developed or updated more recently were more likely to include policy measures related to shared and ODM and AVs. Among the seven CAPs that did not address ODM and AVs, six were adopted in or before 2012, and only one was developed in 2015. The CAPs that included a minimum of five policy measures were all adopted in or after 2016. San Rafael's plan that included a record of seven relevant policy measures were adopted in 2019. As expected, this finding suggests that municipalities are more likely to recognize the potential GHGs impact of ODM and AVs when updating their CAPs.

Climate Action Plans Typically Include Several Measures Relevant to Autonomous Vehicles and On-Demand Mobility Measures
Although CAPs included different mixes of policy options, some categories were more commonly mentioned than others. The most common type of relevant policy measures dealt with ridesharing and carpooling, with 10 CAPs recommending a ridesharing measure and nine CAPs recommending carpooling measures. As a part of their TDM strategies, a total of 14 CAPs included policy measures to encourage ridesharing or carpooling specifically. Encouraging vanpooling and car-sharing were frequently mentioned-a total of seven CAPs incorporating either or both measures into their TDM program.
CAPs recommended various types of action to encourage ridesharing (including carpooling and vanpooling) and car-sharing. For example, many CAPs incorporated specific measures to incentivize and educate city employees to benefit from these mobility options. In addition, or as an alternative to programs designed for city staff, several CAPs recommended working with employers (especially major employers) and transportation funding agencies to incentivize (or remove the disincentives from) these mobility options. Examples include the City of Hayward's CAP, which recommends helping businesses (particularly large employers such as colleges and the Hayward Unified School District) to develop  and implement car-sharing programs. The City of Oakland's CAP recommends encouraging and assisting employers and transportation funding agencies to offer support for a variety of mobility options that reduce the need for driving, including but not limited to ridesharing, car-sharing, carpooling, and vanpooling. The City of Santa Rosa's CAP recommends working specifically with large employers to develop ridesharing programs, including carpool and vanpool alternatives. Furthermore, Freemont's CAP recommends requiring employers to offer preferential parking for carpools. Additionally, CAPs included measures meant to benefit the entire community and disadvantaged groups more broadly. Examples include the integration by Los Angeles of carsharing services into the first and last-mile infrastructure improvement program around transit stations, and Berkeley's action item of providing car share subsidies for low-income residents.
The broader category of shared mobility, which includes any shared transportation service among users ranging from public transportation and shuttle services to ridesharing and scooter-sharing, was explicitly mentioned in six CAPs. Examples of relevant shared-mobility programs and policies include Freemont's ''commuter shuttle service'' program that connects business districts to major transit stations. Menlo Park's shuttle program offers ''around-town'' transportation. San Francisco's ''Hall of Justice Employee Shuttle'' provides close to 20,000 passenger trips a year to and from the Civic Center Station. The City of Palo Alto has increased shared transportation ridership rates through various programs. And the City of San Jose's partnerships with relevant organizations to collect and analyze data related to shared mobility (to gain insights for better incorporation of shared-mobility options into the City's CAP).
Mobility on demand and ridehailing measures were each mentioned in five CAPs. Current technologies empower individuals to benefit from on-demand information, real-time data, and even predictive analysis to meet their transportation needs better. As several CAPs have viewed mobility on demand and ridehailing as an effective way to alleviate the limitations of shared mobility and alternative transportation modes. For example, ''guaranteed'' or ''emergency'' ride home programs (that guarantee participants using alternative transportation modes a ride home in case of unexpected emergencies) as well as ''on-demand shuttles'' or ''microtransit'' have been recommended by several CAPs. Nevertheless, among the CAPs that stress the importance of mobility on demand, only a few propose action items that specifically focus on using technology-enabled services. Examples include Berkeley's marketing and outreach efforts to promote the development of real-time or dynamic ride-matching. Palo Alto's strategy of facilitating dynamic commute ridesharing and promoting the use of various smartphone applications. And Santa Monica's promotion of ''microtransit,'' which the city defines as technology-enabled private shuttle services with dynamic routes (rather than fixed routes) and stop locations (as opposed to door-to-door services). A few cities have also proposed the innovative option of combining the facilitation of ridehailing with zero-emission vehicles to enhance the GHGs reduction potential of their relevant policy measures. For example, the City of San Rafael's CAP calls for encouraging or requiring ridehailing (and delivery service companies) to use zeroemission vehicles.
Four recently updated municipal CAPs specifically mentioned shared autonomous vehicles. Most interestingly, all these CAPs combined preparation for AVs with GHG emission reduction and transportation equity and accessibility goals. For example, the City of Los Angeles's 2019 CAP, entitled ''LA's Green New Deal,'' proposes initiatives to ensure that AVs are used effectively for sharing services and are electric. Meanwhile, LA's 2019 CAP stresses the importance of analyzing transportation data and creating design guidelines for AV infrastructure to ensure equitable distribution of app-enabled mobility services across the city. Although the City of Santa Monica's 2019 CAP views AVs as an electrified and shared-mobility option, it also acknowledges the need to plan for future use of AVs to minimize the possibility of adverse impacts, such as increased VMT or congestion, or jeopardized road safety. Similarly, the City of San Jose's 2018 CAP calls for regulation to reduce the GHG and VMT impacts of AVs by making driving alone more expensive and promoting mode shifts. San Jose also plans to partner with public and private organizations to ensure the accessibility and affordability of AVs to low-income individuals. Lastly, San Rafael offers a different measure to reduce GHGs from AVs: limiting the idling of AVs through public engagement campaigns.
Another alternative to combine GHG reduction and transportation accessibility goals focuses on ridehailing. For example, the City of San Jose is evaluating options, such as discounted group electric vehicle (EV) purchasing or permitting incentives, to encourage ridehailing companies to use EVs. Meanwhile, the City of Los Angeles partnered with a ridehailing provider to help connect residents to public transit.
MaaS is yet another relevant term discussed in municipal CAPs that is meant to offer a ''consumer-centric'' model of transportation through streamlining ''journey planning.'' MaaS eliminates the need for separately planning, booking, and paying for various transportation services (including shared and micromobility offerings) to get to a final destination. MaaS can reduce barriers to using alternative modes of transportation and shared mobility, thus reducing VMT and GHG emissions. Examples of measures or programs incorporating MaaS into municipal CAPs include the City of Palo Alto's measure to promote and facilitate apps that offer seamless mobility payment and booking options and the City of Los Angeles's partnership with a ridehailing company to connect nearby residents to public transit either free of charge (for those enrolled in the low-income transit subsidy program) or for a small fee using a Transit Access Pass (TAP) card.

Findings from the General Plan Analysis
This section discusses key findings from the analysis of GPs. As with the CAP analysis, we looked at patterns of how many AV or ODM measures appear in each GP, trends over time, and patterns of how frequently different types of AV or ODM measures appear in the plans ( Table 2). The analysis shows that GPs have somewhat fewer measures than CAPS, but that the patterns are otherwise quite similar to those in CAP analysis.
GPs were somewhat less likely than CAPs to offer relevant measures to AVs and ODM GPs were somewhat less likely than CAPs to have adopted policy measures related to shared and ODM and AVs (see Table 2). Out of 23 GPs analyzed, five plans included four or five, while six plans included two or three relevant measures. Three other plans included only one relevant measure, and the remaining nine plans did not specifically mention a single measure in the relevant policy categories.

Patterns of Relevant Measures to Autonomous Vehicles and On-Demand Mobility are Similar in General Plans and Climate Action Plans
Like CAPs, the most common relevant policy category included in municipal GPs was carpooling, with 10 municipalities explicitly having adopted at least one relevant policy. These municipalities have adopted TDM policy options to encourage commuters to carpool, such as the provision of carpool parking, community outreach initiatives to encourage carpooling, TDM programs for major employers and school districts, and guaranteed ride home programs. For example, the City of Berkeley's ''Trip Reduction'' policy specifically mentions ''carpooling and provision of carpool parking and other necessary facilities'' as a mechanism to reduce automobile traffic and congestion. Within the same policy measure, Berkeley proposed programs to facilitate carpooling through neighborhood-level initiatives. Additionally, Berkeley's GP includes a policy measure to encourage private employers to reduce the demand for automobile travel through carpool incentives. The GPs of Menlo Park and San Rafael aimed at expanding the effectiveness of their TDM programs by proposing to specifically encourage carpooling for school trips in addition to work trips. On the other hand, Napa adopted a policy to encourage commercial developers to provide preferential parking for carpools for projects likely to employ at least 50 people. As for Hayward, its GP stressed the importance of creating ''Transportation Management Associations'' and eliminating barriers to carpooling through various programs, such as ''guaranteed ride home'' programs.
These diverse examples show how municipal plans have considered different strategies to encourage carpooling as a more desirable transportation option than driving alone.
Shared mobility, car-sharing, and ridesharing were explicitly mentioned in six, and vanpooling in five municipal GPs. These categories have been considered effective first-and last-mile solutions by municipal GPs that can eliminate or alleviate barriers to the use of public transit. Specific attention has been given to transit-dependent or vulnerable populations, such as the disabled, seniors, and youth. For example, Berkeley's GP includes a ''Special Transit Program'' that offers ''senior vans'' to improve mobility for the elderly. Additionally, beyond TDM strategies for major employers, several cities have also developed district-specific programs that facilitate shared mobility in high-traffic or high-demand areas. Examples include Santa Cruz's shuttle services for the downtown area and other major employment centers; Menlo Park's shuttle service connecting employment centers and the Downtown Menlo Park Caltrain station; and Berkeley's ''no-fare shopper shuttles'' that connect shopping districts in the entire city.
Similarly, ridehailing and mobility on demand have both been mentioned in two municipal GPs as strategies to remove barriers to the use of public and alternative transportation modes. For example, Palo Alto's GP emphasizes the need for services that ''complement and enhance'' alternative mobility options available to their residents and ''expand transit access,'' including but not limited to ridehailing services and on-demand local shuttles. As a part of the city's ''Employer-based Strategies,'' Hayward's GP mentions mobility on demand strategies, such as guaranteed ride home programs to strengthen the chances of success for employer-based TDM strategies.
Only three out of 23 municipal GPs included provisions for relevant emerging transportation technologies, namely connected autonomous vehicles (CAV). Among these three cities, only the GPs of Palo Alto and Menlo Park briefly focus on possible opportunities for GHG emissions reduction from these technologies. Both of these GPs stress the importance of supporting or funding emerging technological advancements, such as but not  limited to CAVs and AVs, sharing technology, and EV technology to reduce air pollution and GHG emissions and to enhance access to mobility for all. Winsor's GP, on the other hand, focuses primarily on the potential impacts of driverless vehicles on the streets of the Town, such as impacts on roadway design, signage, and speed limits. No GP included measures related to ridehailing, specifically how to encourage ridehailing companies to adopt technologies and practices that can help reduce GHG emissions.

Conclusion
Analysis of the literature, municipal CAPs, and GPs yielded important findings that lead to four key points: 1) Cities should consider synergies between AVs and ODM during policy and planning discussions about either one. The literature focusing on vehicle automation technologies overlaps with that of ODM. This is mainly because of the synergies between AVs and ODM that may help amplify adoption and benefits of both while reducing the risk of adverse environmental or social impacts. For example, AVs can boost carsharing by eliminating the need for someone to travel to a car-sharing facility to access available vehicles; they can also improve safety and convenience (21). On the other hand, if AVs are shared and used as a mobility service (as opposed to privately owned single-occupancy vehicles), concerns about increased traffic, VMT, and GHG emissions are significantly reduced. Shared AVs (or SAVs) are also more likely to be accessible to a wider range of users making their widespread and equitable adoption possible. Because of the synergies between AVs and ODM, any discussion of the maximization of benefits or minimization of risks should consider both emerging trends. 2) Maximizing the environmental and social benefits of AVs and ODM requires proactive and progressive planning. A comparison of findings from the literature and analysis of municipal CAPs and GPs shows that the often claimed environmental and social benefits of AVs and ODM will not be realized without a comprehensive strategic vision about what an ideal transportation system should look like and what steps communities should take to get there. Lessons learned from TDM strategies adopted by municipal planssuch as the need to combine various awareness, pricing, and incentive-based strategies to influence mode choice and travel demand; or the importance of effective collaboration between transportation agencies, local governments, businesses, and nonprofit organizations-can still be relevant in a driverless future. Similarly, land-use policies adopted by local plans to encourage high-density, mixed-use, and in-fill development or planning efforts to build walkable and transitfriendly communities are still useful tools to reduce VMT and GHG emissions. Nevertheless, AVs and ODM offer new opportunities and pose new challenges for communities that should not be ignored in planning efforts.

3) Municipal CAPs and GPs in California have
adopted several strategies and programs relevant to AVs and ODM. Since several of the commonly used TDM strategies, such as programs or policies to encourage carpooling, are applicable to AVs and ODM, most municipal CAPs analyzed included at least a few relevant measures. The more recently updated CAPs were more likely to include a more significant number and more closely relevant measures to AVs and ODM, such as initiatives to ensure that AVs are shared and electric, more accessible to low-income individuals, and more efficiently used by minimizing idling time. Other innovative measures adopted by recently updated CAPs involve measures to encourage TNCs to invest in EV; programs to promote MaaS through apps that offer seamless mobility payment and booking options; and partnerships with ridehailing companies to connect nearby residents to public transit either free of charge or for a small fee.
As expected, municipal GPs were far less likely to include explicit interventions to ensure that AVs and ODM help communities reduce GHG emissions. The few plans that did include provisions for relevant emerging transportation technologies of interest focused predominantly on bigger picture ideas, such as supporting research and development for AVs and other technological advances and planning for infrastructure investments and improvements. 4) Several untapped opportunities exist to harness the GHG emissions reduction and social benefits potential of AVs and ODM. A comparison of findings from the literature review and analysis of municipal CAPs and GPs in California uncovers untapped opportunities to seize the GHG emissions reduction and social benefits of AVs and ODM. The following section details ways and mechanisms through which CAPs can help communities plan for environmentally responsible and socially equitable adoption of AVs and ODM.

Policy Recommendations
The study findings outlined above suggest seven specific ways in which local governments could use CAPs to harness the GHG emissions mitigation and equity potential of ODM and AVs.
1) Use CAPs to build equity into a shared and driverless mobility future. Climate action planning and policy interventions must engage with the notion of just and equitable communities. Thus, existing or common measures used by CAPs can be strengthened to guide the equitable distribution and use of AVs and technology-enabled ODM (22). The new generation of CAPs acknowledge more prominently that effective climate action planning is rooted in social justice and equity. Most of these CAPs stress the importance of protecting the most vulnerable among our communities and prioritizing resources to combat inherent inequities in our society, such as lack of access to safe, affordable, and convenient public or active transportation options. Since AVs and ODM options present both an opportunity to alleviate the equity gaps in our current transportation system and a risk of exacerbating such inequities (23), local governments should ensure that their CAPs employ specific measures to maximize the potential benefits and minimize the risks. For example, CAPs can include policy and programmatic interventions to encourage or incentivize the use of shared AVs and ODM options as affordable and convenient first-and last-mile solutions. More specifically, co-locating shared AVs with public transportation stops, single fair payment for transit and shared AVs, and provision of one-stop real-time information for both services are examples of strategies to better integrate shared AVs with other public transportation modes. Promoting shared vehicles and shared rides can generally lower costs and increase access to AVs. CAPs can also encourage access to shared AVs across various socio-economic groups and neighborhoods by fair placement of such services and lowering rates for low-income individuals. Additionally, CAPs can help bridge the digital divide by making app-enabled mobility options more accessible and affordable. Lastly, CAPs can foster participation of disadvantaged and vulnerable communities in the shared-mobility planning and decision-making processes. 2) Use CAPs to help align comprehensive GHG emissions reduction strategies for AVs and ODM with broader GP mobility goals. As discussed in the findings section of this paper, both municipal CAPs and GPs may include measures relevant to AVs and ODM. Nevertheless, CAPs are more likely to offer a clear and comprehensive guide for developing, coordinating, and implementing community programs to reduce GHG emissions and adapt to the adverse impacts of climate change. In other words, GPs are more suited to provide a broader vision; CAPs are more appropriate for providing detailed guidelines and innovative solutions specifically designed to combat climate change. As such, a detailed GHG emissions reduction roadmap for AVs and ODMwhich helps align existing efforts, prioritize actions, and monitor implementation-can be adopted to reach climate targets and mobility equity goals. The roadmap can be linked to existing TDM strategies and physical transportation infrastructure strategies, land-use policies, and regional coordination efforts highlighted in the CAPs. The CAP can then be linked to the GP to reinforce its broader mobility goals. This will ensure that strategies for AVs and ODM are aligned with both CAP and GP goals as well as GHG emission reduction targets. 3) Encourage travelers to make a long-run shift to shared use of AVs and ODM. There is a consensus in the literature that many claimed benefits of AVs and ODM, such as reduced VMT, GHG emissions, and traffic, will only be realized if these technologies make shared mobility more economical, flexible, and convenient, and by extension, more common or desirable. The widespread availability of app-enabled ODM options, dynamic geo-positioning technologies, and ease of electronic financial transactions have cleared the significant hurdles of carpooling. Furthermore, AVs can help reduce or eliminate safety incidents, such as crashes and even assaults. Nevertheless, additional incentives might be required to shift the mobility preferences of individuals who always relied on private vehicles.
TDM strategies recommended by CAPs, such as preferential parking for carpools, employee subsidies for carpooling, shuttle programs for business and entertainment districts, and guaranteed ride home programs for commuters who carpool or otherwise use public or active modes of transportation, can be a good start. Nevertheless, most of these strategies have been designed for static ridesharing and do not necessarily reflect the opportunities and challenges offered by AVs and dynamic ridesharing technologies that better support impromptu trips. Thus, there is a need to redesign TDM strategies recommended by CAPs to encourage shared use of AVs and ODM and help shift mobility preferences of individuals toward shared mobility in the long run. California's SB 1014 (2018)-the Clean Miles Standard and Incentive Program-has fueled discussions for developing innovative ways to reduce GHG emissions through ODM and TNCs. 4) Use a combination of transportation and landuse policies to prevent increasing sprawl resulting from the deployment of AVs. Local CAPs typically recommend various transportation and land-use strategies to combat sprawl, ranging from in-fill and transit-oriented development strategies to eliminating parking minimums. To ensure that the increased comfort and reduced value of travel time (resulting from the reduced opportunity cost of driving) associated with AVs will not inadvertently result in sprawl, local CAPs should use both transportation and land-use progressive policy options. It is important to note that the combined effect of transportation and land-use policy options is often more significant than the effect of one type of policy. This is because transportation and land-use policies work together in affecting travel behavior. For example, by eliminating parking minimums, CAPs can encourage shared use of AVs and discourage the private ownership of AVs. If most or all AVs are shared and used as an on-demand service, the need for parking space will further diminish, resulting in in-fill development opportunities. We should not disregard the synergic effect between transportation and land-use policies. 5) Stress the importance of energy efficiency and renewable energy in a driverless future. The biggest motivation for the development and deployment of AVs is increased safety and convenience-a robot will replace the driver, and it will follow all traffic rules and cannot be distracted. Other potential advantages of AVs, such as reduced GHG emissions, are considered cobenefits. Manufacturers do not necessarily guarantee these co-benefits. Manufacturers might be tempted to build larger vehicles that can serve other purposes, such as an office, a gym, or a movie theater. These larger vehicles can be even more energy consumptive than the current singlepurpose vehicles. Local CAPs can help develop and adopt specific policies to ensure that AVs are energy efficient and/or electric. For example, local governments can change zoning codes to allow or require charging infrastructure for future development and streamline processes for approval of privately owned charging stations available to the public. Governments can also privilege shared and electric AVs through provision of free or priority parking, reduced price tolls or access to high occupancy toll (HOT) lanes, and lower fees for ODM trips. In addition to supporting the electrification of transportation, local CAPs can also encourage or require renewable energy in electricity generation. For example, local governments can permit or incentivize property owners to install solar panels and EV chargers as a package. 6) Identify opportunities to link AVs and ODM to transit. One major challenge associated with the widespread deployment of AVs is the potential for declined transit ridership, decreased public transportation funding, and eventually reduced options for those who do not have access to a car. However, declined transit ridership followed by reduced funding and transportation options is not the only possible scenario; the alternative scenario is that AVs and ODM options will be used to augment and complement public transportation. CAPs typically offer various options to enhance the viability of public and active modes of transportation, ranging from local initiatives to regional coordination for rail service infrastructure. CAPs also include first and last-mile solutions, such as micromobility and microtransit services, to boost transit ridership. A combination of these strategies can be specifically designed to use the opportunities offered by AVs and appenabled ODM options to connect individuals to transit stations easily or fill the mobility gaps in areas with limited or nonexistent transit options. For example, one simple but effective strategy is developing web-based streamlined trip planners that offer real-time departure predictions and eliminate the need for checking different transit maps or websites, planning for the trip to and from transit stations, and purchasing separate fare passes. Another strategy is offering discounted ridehailing services to and from transit stations. In sum, making the transit experience better and easier involves planning for the entire trip, not just the transit portion. 7) Incorporate planning tools that respond to the uncertainty related to the deployment of AVs and extensive use of ODM technologies. Since climate change poses many uncertainties, CAPs have long considered sophisticated and dynamic methods to deal with uncertainties. For example, scenario analysis is a powerful tool used by CAPs to project possible alternative outcomes based on scientific and economic factors and policy interventions. CAPs have also acknowledged that uncertainties can discourage action and thus recommended techniques to help stay focused on the desired goals or outcomes. For example, back casting-a planning technique that first defines a desirable future or goal and then works backward to identify policy and programmatic interventions that connect the present conditions to the desired future outcome-is commonly used by CAPs. These common methods of dealing with uncertainties through CAPs can help local governments envision a desirable mobility outcome in a driverless future and ensure that deployment of AVs and more extensive use of ODM will help us reduce GHG emissions VMT as well as improve mobility for all.