By Bryn Grunwald, Heather House, & Jacob Korn
It’s widely understood that if we are to avoid the disastrous effects of climate change, the United States will need to electrify its transportation sector, which contributes the most emissions of any other. What’s less understood is that even under the most ambitious emissions-reduction scenarios, the United States must reduce vehicle miles traveled (VMT) by 20 percent before the end of the decade to maintain a 1.5 degree C scenario trajectory. While both electrification and VMT reduction are needed and both are distinct strategies, there is a ripe opportunity for policymakers to create a symbiotic relationship between the two to deliver equitable, climate-aligned outcomes in their communities.
Electrification efforts have largely focused on replacing internal combustion engine (ICE) vehicles with electric vehicles (EVs). This emphasis is unsurprising given that we are a culturally car-centric country – research shows that the average American drives about twice the number of miles per year as people living in Germany, France, or the United Kingdom. This reliance on personal vehicles is a symptom of a nation dominated by highways and urban sprawl, where few have access to affordable and reliable public transportation, and where cities have a dearth of sidewalks and bike lanes.
Cutting VMT by enhancing accessibility will require a variety of interventions, including enabling more compact development and prioritizing climate-aligned infrastructure investments in bike lanes, transit, sidewalks, etc. which will in turn create an enabling environment for mode-shift away from gasoline single-occupancy vehicles to more efficient modes of transportation such as walking, biking, and public transit.
In 2021, the Bureau of Transportation Statistics found that over half of all trips were three miles or less and 60 percent of all vehicle trips were less than six miles. Given short trips dominate transportation patterns in the United States, policymakers can target short vehicle trips with combined mode-shift and electrification strategies. A combined approach will provide their communities with a powerful way to achieve compounded benefits for accelerated transportation decarbonization. The key to unlock a powerful electrification and mode-shift partnership: electric bikes (e-bikes).
In recent years, a growing number of cities have begun to recognize the environmental, economic, and social benefits of e-bikes. As e-bike sales continue to outpace those of electric vehicles (EVs), policymakers and others are beginning to seriously contemplate ways in which they can make e-bikes affordable and accessible to as many people as possible.
Programs such as Denver, Colorado’s wildly popular e-bike incentive program are showing that policy can be a powerful lever to accelerate e-bike adoption. Its vouchers are routinely claimed within minutes of becoming available, and in 2022 alone, it put more than 4,700 e-bikes on the streets. Denver’s survey of participants shows that the purchasers of these e-bikes biked an average of 26 miles per week.
While the success of programs like Denver’s provides compelling evidence that e-bike rebate programs are effective, there is still a lack of good data on the impacts of e-bikes and many decision makers are looking for further proof points. That’s why RMI created the E-bike Environment and Economics Impact Assessment Calculator for Cities to give policymakers, advocates, and other stakeholders the data they need to make date-driven decisions.
The calculator analyzes the environmental and economic impacts that e-bikes could have if they replace a significant percent of short vehicle trips under five miles. The RMI team used data from Replica to:
- Understand current vehicle travel behavior in cities;
- Model possible changes to travel if short-distance vehicle trips were replaced by e-bikes; and
- Analyze the changes that would stem from an e-bike incentive program.
The calculator has two impact assessment scenarios that policymakers, city staffers, or other stakeholders can utilize: 1) assessing the city-wide impact of e-bikes based on a percent of short vehicle trips replaced with e-bikes and 2) assessing the impact specifically derived from a city e-bike incentive program. Both produce insights into how much greenhouse gas emissions, air pollutants such as NOx, PM2.5, and carbon monoxide, and vehicle miles traveled (VMT) would decrease as a result. Users can also see how much money e-bikes can save consumers, due to their low fuel and maintenance costs.
The first scenario is of particular use to policymakers and staffers who may be interested in setting a community-wide mode-shift and/or e-bike target and understanding how that outcome would contribute to their climate action plan and equity goals. The second scenario is of particular use to policymakers and staffers interested in developing an e-bike incentive program for their community and understanding its benefits, or for communities with incentive programs that would like to assess their benefit. Users are able to input their own variables and see the potential impacts of the proposed program.
How RMI determined which cities to profile
RMI included data for more than 220 cities to ensure that all states in the lower 48 had at least one city in the calculator. The included cities come from People for Bikes’ city rankings, which measure cities’ bike infrastructure. If a state did not have cities in the bike rankings, RMI selected cities by population size.
RMI used Replica’s Thursday and Saturday Fall 2022 travel datasets for all the cities included in the calculator. RMI then loaded the datasets into R and filtered them so that only trips taken by vehicles – either as rideshare, passenger, or private automobile.
The dataset was further filtered to remove trips taken by individuals younger than 18 or older than 75, and to filter out trips that were under 0.1 miles. Vehicle trips under 0.1 miles were assumed to be an error in the data. RMI chose this age range to account for adults who would qualify for incentive programs, with the higher age limit coming from SANDAG’s Pedal Ahead program.
RMI is exploring adding an option in a future iteration of the calculator that will include trips taken by teenagers, as e-bikes would allow for them to independently travel without having to use a car.
The RMI team counted how many trips occurred at tenth-of-a-mile intervals between 0.2 miles and 5 miles. Replica offers a breakdown of miles to the tenth of the mile for trips, which allows for detailed understanding of trip lengths. The Thursday data was multiplied by 5 and the Saturday data was multiplied by 2 and then added together to create an estimation of weekly trip behavior. This approach helped calculate the trip replacement rates for cities by replacing a portion of current vehicle trips at every tenth-of-a-mile breakdown with e-bikes.
RMI also used Replica data to understand changes to vehicle miles traveled (VMT) if e-bikes are adopted at scale. To do so, the team added all miles from all vehicle trips taken by residents between the ages of 18 and 75 from the Fall 2022 Thursday and Saturday datasets, which had been converted to estimate weekly numbers. The number of miles e-biked were subtracted from the overall total VMT to create an estimate of changes to VMT as more e-bikes are used.
Snapshot of benefits derived from e-bikes in the nation’s top 10 most populous cities
Looking at the United States’ 10 largest cities, more than 50 percent of weekly vehicle trips are under five miles.
Cutting these weekly vehicle trips under five miles by 25 percent could produce the following benefits:
E-BIKES' ENVIRONMENTAL BENEFITS
Across the 10 cities, over 25,500 metric tons of CO2e/week could be avoided, the equivalent of avoiding 2.7 million gallons of gasoline or over 58,000 barrels of oil. This is also the equivalent of what could be replaced if seven wind turbines were brought online. Furthermore, replacing a quarter of short trips in these 10 cities over the course of a year could translate to over 1.3 million metric tons of CO2e avoided or 144.5 million gallons of gasoline avoided or 3 million barrels of oil; to put that into context-- the emissions reductions is equivalent to closing three natural gas plants - or the same greenhouse gas emissions avoided by 369 wind turbines running for a year.
Switching to e-bikes for short trips would also help cities meet VMT reduction goals that contribute to broader transportation and climate goals, as switching 25 percent of the short vehicle trips would cut overall VMT by 3 percent on average across the ten cities within ten years. Per week, these reductions equate to the reduction of over 7,600 Americans’ total annual driven miles. The table shows the weekly and monthly vehicle miles traveled reduced in each city over ten years with a quarter of vehicle trips under five miles switched over to e-bikes. The average American drives approximately 1,200 miles a month, meaning that cutting vehicle trips in the 10 largest cities would be the equivalent of removing tens of thousands of cars from the road. This will contribute to outcomes such as congestion relief.
E-BIKES' ECONOMIC BENEFITS
Switching short vehicle trips to e-bikes would also help residents save money. If a quarter of vehicle trips in the ten most populated cities were switched to e-bikes in ten years, this would reduce money spent on fuel and maintenance by 16 percent over 10 years and saving users more than $20 million weekly. Over a month of replacing a quarter of short vehicle trips with e-bikes, this could add up to over $89 million in savings from less fuel usage and reduced maintenance. E-bike maintenance is often relatively inexpensive, as many mechanical problems can be addressed by the user themselves without requiring a shop, and parts are relatively inexpensive for the physical systems.
If bike infrastructure was built out to a high level of comfort, some households might feel comfortable getting rid of a second or third car, saving even more money from reduced car payments, insurance costs, and other aspects such as registration, parking, and emissions testing.
E-BIKES' SOCIAL BENEFITS
While this tool does not measure e-bikes' effects on health outcomes or economic mobility, it’s fair to say that widespread e-bike adoption would likely improve both.
As the American Lung Association notes, today, over four in ten Americans — more than 135 million people — live in communities impacted by unhealthy levels of air pollution, which translates to increased rates of asthma attacks, heart attacks and strokes, lung cancer and premature death. These poor health outcomes are not shared equitably, with many communities of color and lower income communities at greater risk due to increased exposure to transportation pollution. Switching a quarter of vehicle trips in the ten most populated cities to e-bikes would cut down on PM2.5 by 22%, compared to continuing to drive these trips. PM2.5 comes from the brakepads and tires of vehicles, as well as the combustion of fuels, and has significant health impacts, such as rising rates of cardiac, vascular, neurological and pulmonary disease and some types of cancer. Gas powered vehicles also produce nitrogen oxides (NOx) from the combustion of their fuels, which can harm the respiratory system and increase risk of asthma or chronic lung diseases. Reducing the use of vehicles in city environments, where people are likely driving less than five miles, would help alleviate some of the health problems caused by air pollution coming from vehicles.
Furthermore, e-bikes can enhance equity goals, such as improving access to opportunities in transit deserts. The National Renewable Laboratory (NREL) ran a pilot with the Colorado Energy Office to distribute e-bikes to low-income essential workers in diverse locations around Colorado. The pilot showed that the e-bikes served unmet transportation needs, such as accessing employment. In some areas of Colorado, the bikes were shown to be competitive with cars, with the travel speeds and timing being near-parity, with much lower costs for bike maintenance while also consuming less energy.
Parting Insights
While the calculator does not yet analyze how safe and connected bicycling infrastructure can promote increased ridership, it is important to acknowledge that the public must feel safe riding a bicycle to effectively shift trips from vehicles to e-bikes and realize their benefits. States, cities, counties, and metropolitan planning organizations are responsible for significant portions of the nation’s transportation planning and can direct funding to protected bike lanes and related infrastructure that will encourage ridership. Implementing these changes to our streetscapes in cities and suburbs alike will generate emissions and economic savings, while creating more livable, thriving communities for all.
Please reach out to the RMI team with any questions about the underlying calculations or let them know if your city is not included in the tool and we will add it in our next update.
