EV in LA

The advent of electric vehicles (EVs) in shaping urban dynamics and advancing sustainable development has led to the emergence of concepts like "EV-friendly city."

In 2020, ChargePoint, the company with the nation’s largest electric vehicle charging station network, released a  list  of the Top 10 Metropolitan Areas for electric vehicles. Scored by the number of EVs owned and the number of public charging stations available on the ChargePoint network, the San Francisco Bay Area led the nation according to the list, followed by Seattle, San Diego, Austin, and Honolulu, with Los Angeles in the sixth place.

In 2022, a Forbes  analysis  ranked the Top 25 EV-friendly Countries around the world based on five metrics: 1) number of EV sales, 2) number of charging points per capita, 3) average price of electricity, 4) percentage of energy from renewables, and 5) road quality. According to the results, Switzerland leads the world, the top 10 countries are all European, and U.S. ranks the 22nd.

What is "EV-friendly?"

What factors contribute to this friendliness?

How does defining the concept inform our understanding of EVs as a driver in infrastructure planning and energy sustainability?

How could innovative spatial analysis inspire the definitions of, discussions over, and discourse on EV friendliness in the context of sustainable cities?

Following the framework driven by these questions, this project features Los Angeles as a case study in exploring some of the answers. Specifically, the analytical process 1) experiments with the application of the Two-step Floating Catchment Analysis method in the novel context of charging accessibility evaluation, 2) initiates an effort to represent infrastructure service through dynamic charging sessions instead of static charger counts, 3) identifies gaps in quantitative and spatial studies to understand accessible EV infrastructure and planning, and 4) offers thoughts on potential angles to expand this branch of research.

LA Context

Los Angeles is taking a great leap with its commitment to increase the percentage of zero-emission vehicles on city roads to 25% by 2025, 80% by 2035, and 100% by 2050. The city’s goal to eliminate vehicle emissions is part of its vision to address climate change, improve air quality, and achieve environmental justice.

Most electric vehicle charging is likely to continue at home, where it is less expensive and more convenient than public options. However, a report projected that by 2030, direct current fast chargers in Los Angeles will need to grow by a factor of 33 to about 3,900 chargers, while public Level 2 chargers will need to increase by a factor of 8 to about 21,500 chargers. Workplace charging will need to increase to at least 25,000 chargers by 2030.

In April 2022, Los Angeles passed a master plan that would ramp up its electric vehicle and charging infrastructure. According to the city council, the plan will include detailed assessments of vehicle needs; the required charging infrastructure; expanded charging capacity for the growing number of privately owned electric vehicles; and the impacts of this expansion of electric vehicles on the LADWP power grid and LA100 clean energy plan.

EV Basics

There are three levels of EV charging (Level 1, Level 2, and Level 3), and the higher the level of charging, the faster the charging process. Level 3 fast chargers can be further broken into DC Fast Charging and (Tesla) Supercharging.

Level 1 adds between 3 and 5 miles of range per hour. It works well for plug-in hybrid electric vehicles (PHEVs), which have smaller batteries, but it is too slow for most daily charging for EVs whose batteries are much larger, unless the vehicle isn’t needed to drive very far on a daily basis. 

Level 2 charging is the most commonly used level for daily EV charging and the most used for residential EV charging. It can be installed at home, at the workplace, as well as in public locations. It can replenish between 12 and 80 miles of range per hour, capable of completely charging a vehicle with a nearly empty battery overnight.

Level 3 charging is the fastest type of charging available and can recharge an EV at a rate of 3 to 20 miles of range per minute. Unlike Level 1 and Level 2 charging that use alternating current (AC), Level 3 charging uses direct current (DC). The voltage is also much higher than Level 1 and 2 charging, which is why Level 3 chargers are seldom installed at home.

This project utilizes two public datasets: 1) zero-emission vehicle registration data from the Department of Motor Vehicle, and 2) EV charging station data from the Alternative Fuels Data Center. Both datasets are available as dashboard formats: the zero-emission vehicle registration can be downloaded in a csv, and the EV charging station data can be requested in a variety of formats using SQL query and an API.

Zero-emission vehicle registration data cover the entire California state and include three types: plug-in hybrid electric vehicles (PHEVs), electric vehicles, and hydrogen. The first two types were filtered for the purpose of this project. To further filter out Los Angeles, zip code area lists were acquired from open-source  datasets  and  USPS . Fictional/Placeholder ZIP codes 99999 and any that fell on California-Nevada boundaries were removed during cleaning.

With the second dataset, query phases "California" and "ELEC" (which stands for electric chargers) were used. The operation hours column, which has non-standardized qualitative inputs, was manually examined and assigned unified hour codes that approximate their availability. This is to prepare for converting service availability from charger counts to charging session counts. The total count of EV chargers for each location was calculated by summing Level 1, Level 2, and Level 3 chargers. After the cleaning, the city column was filtered for Los Angeles to project the coordinates onto the map.

Interact with the data dashboards below.

The flowchart below details the project’s three-part analytical process: 1) statistical data cleaning and analysis; 2) spatial data preparation and exploratory analysis; 3) 2SFCA process and accessibility indexes. Key spatial analytical processes are described below.

Three levels of spatial scales were used: zip areas, neighborhoods, and census tracts. First, I generated random points that represent EV registrations for each zip area to acquire a point data set of EV registrations across Los Angeles. Second, I spatial joined the point dataset to neighborhood and census tract boundaries to acquire EV registration counts by neighborhoods and by census tracts (this finer resolution can create more informative catchment areas for index calculation). Third, I used the Identity and spatial join tools when converting the accessibility index by census tract back to the neighborhood scale.

Approximating 5 to 10 minutes of drive, the distance of 3 miles was selected to create catchment areas. When calculating the service (charging session) to population (EV registration) ratio, a normalization factor of 10 was used (aka the ratio means average charging sessions per 10 EVs) as based on research, it is a widely referenced heuristic.

*charger count to charging session conversion was based on standardized operation hours and estimated charging session length data from: https://www.nature.com/articles/s41597-021-00956-1

Exploratory analyses of the statistical datasets are captured below and grouped under the sub-headline questions. They include interesting contextual findings that were not included in the spatial analysis.

As of September 2022, there are a total of about 73,200 EV registrations in California, where total vehicle ownership is about 17,766,00 (2010 data). The breakdown of registration counts by county is detailed in the Top 10 and Bottom 10 charts below. Los Angeles, Orange, Santa Clara, and San Diego lead with 100,000+ registrations, with Los Angeles (338,573) further leading the others by almost three folds. The Bottom 10 list reveals less obvious trends, but in general, metropolitan and urban areas have more EV registrations.

A level further from county to city: as of September 2022, Los Angeles has about 73,200 EV registrations in total, where vehicle ownership is about 6,433,000 (2010 data). Detailed rankings of the cities are outlined below. The five leading cities--Los Angeles, Santa Clara, Sandiego, San Francisco, and Irvine--are all in different counties. In Los Angeles County, there are 10 cities with fewer than 10 EV registrations.

Most of the charging stations in in LA are public, as shown by the first chart below. However, if we break it down to the number of chargers, as shown by the second chart, the ratio is less dominated by the public. This reveals that private charging stations are more likely to offer greater number of chargers, which can impact EV driver behavior as well as charging session availability. The third chart shows the breakdown of charger types in public stations. The majority is Level 2, with a portion of Level 3, and a few Level 1. While the overall landscape looks robust, with the goal of ramping up EV infrastructure and transportation, there might need more Level 3 chargers to offer more charging capacity.

Breaking down charger locations even further: let's take a look at their urban contexts.

As shown by the chart on the right, most private chargers are located in hospitals, government (state or municipal), parking and garage, and utility (LADWP). The dominant group others take into account scattered chargers on the streets or do not belong to any organization, which reveals the need to systematically offer more charging places.

Other private chargers are associated with urban activities, from office buildings, college campus, to parks. This shows that EV infrastructure planning may impact the way people interact with the urban environment, contributing to building an "EV-friendly" city.

The chart on the right shows a breakdown of public chargers. Similar to that of private, many of them are within utility and parking and garage. However, unlike the dominance of government land use, public chargers have a more dominant presence in a greater variety of urban functionalities, from airports and museums to shopping centers. Corroborating with this prevalence of trend, a  city guide  to EV drivers in Los Angeles featured the Petersen Automotive Museum and The Americana at Brand, among state parks and beaches, as some of the best places to go. This further reiterate the observance that EV infrastructure planning could impact, on a micro-level, driver behavior, and on a macro-level, how populations interact with the cityscape and shape the urban dynamics.

• Which neighborhoods have the most and fewest EV registrations?
• Which neighborhoods have the most EV chargers? What's the public/private breakdown?
• Which neighborhoods have the most Level 3 EV chargers?

The two-step floating catchment area (2SFCA) method is a special case of a gravity model of spatial interaction. While it was developed in the context of accessibility, here we apply it to evaluate EV infrastructures. In essence, it measures spatial accessibility as a ratio of service (charging sessions) to population (EV registrations), combining two steps:

1. It first assesses “charging session availability” at the charging (supply) locations as the ratio of sessions to EVs in their catchment area (a buffer of 3 miles was used for this project, which approximates about 5-10 minutes of drive time). The ratio was normalized by a factor of 10, a heuristics used by many EV analysis.
2. It sums up the ratios (i.e., session availability derived in the first step) around (i.e., within the same threshold travel time from) each EV registration (demand) location.

As shown by the side-by-side map below, it can be observed that many neighborhoods with high EV registrations tend to have low index score, featuring a discrepancy between supply and demand. However, as only public EVs are analyzed, the accessibility issue might be partially addressed with the ownership of private chargers at home.

This project successfully implements an innovative application of 2SFCA to evaluate EV accessibility and constructs a scalable analysis pipeline. However, the methodology may be further enhanced through data and information in the following areas:

• User behavior - optimize EV registration assignment and aggregation at different spatial resolutions (ZIP code, neighborhood, census tract, etc.)
• Charging session time - acquire a more accurate average charging time estimate for different charger groups (workplace, parking/garage, street, etc.)
• Charger availability/ user complaints - improve the accuracy of charger availability estimates by incorporating data that report, for example, user complaints for broken chargers

This project focuses on EV charger spatial accessibility and mainly utilizes vehicle registration and charger distribution data. However, the findings may be expanded by incorporating the following angles for more comprehensive urban planning insights:

• Environmental Justice - how does the current EV charging infrastructure distribution correlate with socioeconomic statuses and environmental justice indexes? is the current planning process burdening the vulnerable/marginal communities? how can we address the equity concerns of infrastructure planning with spatial analyses?
• Urban land use clustering - which type(s) of land use or urban scenes tend to have the most chargers? does the current distribution pattern sufficiently address demand and supply? how may land use and urban function planning inform infrastructure plans to achieve a win-win scenario?

Accurate understanding of the supplies and demands of EV infrastructure is crucial to informing sustainable urban planning and development. However, there has not been much research that examines the EV infrastructure landscape and accessibility, or pipelines to streamline the analyses of EV and charger distributions.

Featuring the City of Los Angeles as a case study, this project proposes a framework that applies the Two-step Floating Catchment Area (2SFCA) method and takes into account chargers’ spatial accessibility over 24 hours. The result found high accessibility index in neighborhoods near the downtown area, decreasing toward the peripheries. Additionally, neighborhoods with the most EV registrations tended to not have access to sufficient charging resources. Consequently, the framework identified potential policy advisories for supplementary infrastructures and shed light on sustainability initiatives like the zero-emission zone pilots.

Bui,A., Slowik P., Lutsey N. (2021). Los Angeles Electric Vehicle Charging Infrastructure Needs and Implications for Zero-emission Area Planning. The International Council on Clean Transportation.

Asensio O., Lawson M., Apablaza C. (2021). Electric vehicle charging stations in the workplace with high-resolution data from casual and habitual users. Scientific Data volume 8, Article number: 168 (2021)

Park, J., Kang J., Goldberg D., Hammond T. (2022). Leveraging temporal changes of spatial accessibility measurements for better policy implications: a case study of electric vehicle (EV) charging stations in Seoul, South Korea, International Journal of Geographical Information Science, 36:6, 1185-1204, DOI: 10.1080/13658816.2021.1978450

Zhang, Y. (2022). Exploring the accessibility of public electric vehicle chargers in England, the UK. Workshop Oxford Electric vehicles, urban development and energy infrastructure: comparative perspectives from the UK and South Korea.

Zhou X. et al. (2021). The measurement method of spatiotemporal accessibility of electric vehicle charging stations in the dynamic time-dependent urban environment. IOP Conf. Ser.: Earth Environ. Sci. 783 012078