Research

The LEVER Institute began with a multi-stakeholder workshop that identified five key research themes that address many of the main micromobility questions faced by stakeholders and are consistent with the expertise of the LEVER research team. We focus on how micromobility vehicle impact transportation systems. 
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The LEVER Institute focuses on aspects of micromobility vehicles that address the interests of both public- and private-sector industry partners. Much of the initial focus was (and still is) on e-bikes and other derivatives (e.g., e-trikes). However, the scope of the institute is broad enough to investigate other unforeseen LEV technologies (e.g., e-scooters). Many of the important questions about LEVs hinge on behavioral aspects of how LEVs are ultimately adopted and used.

The LEVER Institute focuses on the following thrust areas. Click on each or scroll down to learn more about our ongoing or past research:

THRUST 1: BEHAVIORAL ANALYSIS OF MICROMOBILITY VEHICLE USE
THRUST 2: MICROMOBILITY VEHICLE SAFETY AND SUSTAINABILITY IMPACTS
THRUST 3: HEALTH IMPACTS FROM MICROMOBILITY USE
THRUST 4: MICROMOBILITY AND URBAN FREIGHT
THRUST 5: SHARED MICROMOBILITY

THRUST 1: BEHAVIORAL ANALYSIS OF MICROMOBILITY VEHICLE USE

This theme will include research efforts to understand how users consume, use, and value LEV technology. This theme will focus primarily on consumer adoption and use of different LEV variants, with a primary emphasis on e-bike technologies. This theme will also include activities that explore the role of LEVs in shared vehicle and campus travel demand management activities.

The China E-bike Project

Electric bike use has reshaped the transportation system in a large number of cities in China. The massive adaptation of e-bike along with regular bicycles presents challenges common to another mode of transportation. This paper investigates e-bike use over six years with four bi-annual travel diary surveys of e-bike users between 2006 and 2012 in Kunming, China.  Choice models were developed to investigate factors influencing mode-transition and motorization pathways. This effort is meant to identify how to use characteristics or demographics of users change over time and found that unobserved changes occur over time. This paper model these changes over time and introduces a mode-transition model, providing insights into how e-bikes could disrupt the traditional motorization pathway.

Publication:
Use characteristics and mode choice behavior of electric bike users in China
Dynamics of Electric Bike Ownership and Use in Kunming China, Transportation Policy.

Links:
Project

The effect of e-bike incentive programs on adoption

LEVER researchers MacArthur, Bennett, and McQueen (PSU) and Cherry (UTK) conduct research on the effect of e-bike incentives on adoption. The first step in this effort was to assess e-bike incentive programs and how they are used to stimulate the market. That early work, funded by People for Bikes, was pivotal in developing an early white paper (link below) that identifies how incentives can nudge purchase behavior. This work also includes a policy simulator tool that allows users to identify how effective different incentives may be at reducing greenhouse gas emissions. This work is followed by ongoing research funded by the Transportation Research and Education Center (TREC) and People for Bikes that aims to understand individual-level purchase preferences using experimental stated preference methods to understand the levels of incentives and attributes of e-bikes that would cause the highest level of adoption. Our work has been heavily cited and referenced in ongoing incentive policy at state and federal levels.

Publications:
White Paper
Project Brief

Links:
Incentive Tool
Incentive Database

Novel Approaches to Model Travel Behavior and Sustainability Impacts of E-Bike Use

LEVER researchers Cherry and Azad (UTK) and MacArthur (PSU) have partnered with and Bosch E-Bike Systems to measure real-world travel behavior and assess the sustainability impacts of those choices. This National Science Foundation (NSF) funded project develops novel smartphones-based machine learning efforts to assess trip patterns of a panel of e-bike users over two years. This supervised machine learning approach provides a wealth of data on actual e-bike use and avoids some of the pitfalls associated with surveys. However, this dataset compared with ad-hoc travel surveys to supplement passive data collection and, using machine learning algorithms, create the largest and richest dataset to support the growth of e-bike use as a transportation option. The data helps estimate implications on environmental sustainability using behaviorally sensitive environmental models. This four-year project is ongoing and has already amassed a wealth of data and informed policy.

Publication:
https://www.sciencedirect.com/science/article/pii/S1361920920306696?dgcid=coauthor

Links:
Project

National Electric Bike Owner Surveys (2013 and 2018)

Little research has been conducted on e-bikes within North America, especially on the individuals who have purchased e-bikes. The first-known U.S. nationwide e-bike owner survey was conducted by LEVER researcher Macarthur (PSU) in 2013. That study was updated by another nationwide survey in 2018 by LEVER researchers Macarthur (PSU) and Cherry (UTK). Analysis of the survey results indicate that there has been little change in the primary reasons individuals are motivated to purchase an e-bike, and they tend to be related to various barriers which deter individuals from riding a standard bicycle; reducing physical exertion, challenging topography and replacing car trips continue to reign as a few of the most important reasons for buying an e-bike. Importantly, the mode-substitution work from 2018 found that most e-bike trips substitute motorized modes, providing support to the position that e-bikes reduce car-based impacts. Both surveys were funded by People for Bikes and the Transportation Research and Education Center.

Publications:
http://ppms.trec.pdx.edu/media/project_files/NITC_RR_1041_North_American_Survey_Electric_Bicycle_Accessible.pdf

Links:
Project

Understanding the difference between e-bike and conventional bike users

LEVER researchers Cherry and Ling (UTK) and Macarthur (PSU) along with industry partner Weinert (Bosch) studied the differences of the cycling experience and perceptions between e-bike and conventional bicycle users, using samples drawn from independent bicycle dealer customers. A total of 806 respondents in the United States took the on-line survey, including 363 e-bike-owning respondents. The results show that e-bikes play a more important role in utilitarian travel, such as commuting and running errands, compared to a conventional bicycle. Conventional bicycle-owning respondents use their bicycles more for recreation and exercise. Also, e-bike owners tend to bike longer distances and take more trips per week. Both e-bike respondents and bicycle respondents stated that improved health was a key factor for cycling, while Millennials and Generation X respondents cycle to save time and improve the environment. These findings begin to provide insight and a profile of potential new markets for e-bikes in the United States.

Publication:
https://www.mdpi.com/2071-1050/9/9/1662/htm

Evaluation of Electric Bike Use at Three Employment Centers

Employment based e-bike programs are growing in the USA. LEVER researchers MacArthur and Dill (PSU) were the first to evaluate such a program. This study examines the results of a pilot project, which took place April 2014-September 2015 in the Portland region. Participants from three Kaiser Permanente Northwest campuses (1 urban and 2 suburban) were issued an e-bike for 10 weeks to use for various trip purposes, focusing on first/last-mile commuting. Participants were asked to complete three surveys—before, during and after using the ebike—to evaluate how their perceptions and levels of cycling may have changed. Responses were analyzed using statistical software and a GIS. This study’s findings support the general hypothesis that e-bikes enable users to bike to more distant locations, bike more frequently and allow a broader participation in cycling for certain segments of the population by reducing barriers to cycling. This study was funded by the National Institute of Transport and Communities (NITC).

Publications:
https://ppms.trec.pdx.edu/media/project_files/NITC-RR-564B_ME1J9V2.pdf

THRUST 2: MICROMOBILITY VEHICLE SAFETY AND SUSTAINABILITY IMPACTS

This theme will investigate research questions traditionally in the public domain. The primary focus will be the investigation of safety, sustainability, and mobility impacts of LEVs. Safety and sustainability of LEVs in the transportation system can inform policy related to the extent they should be encouraged or discouraged in the transportation system, and on what facilities they should operate.

A crash typology to compare scooter and bicycle crashes

We conducted a comprehensive study to understand what demographics are involved in motor vehicles-involved e-scooter and bicycle crashes, under what circumstances such crashes occur, and what are the mechanisms of such collisions. In the first of its kind study, we compared and contrasted motor vehicle-involved e-scooter and bicycle police crash reports in Nashville, Tennessee, using the recent version of the Pedestrian and Bicycle Crash Analysis Tool (PBCAT). We found that e-scooter and bicycle crashes do not fully overlap with each other. The findings of the study imply that generalized engineering, education, and enforcement treatments to reduce or prevent e-scooter and bicycle crashes, injuries, and deaths might not yield a similar outcome for each mode. This research-to-practice study could help avoid e-scooter and motor vehicle crashes that contribute to 80% fatality of e-scooter riders.

Publications:
Research Paper: Comparison of motor vehicle-involved e-scooter and bicycle crashes using standardized crash typology, Journal of Safety Research

Presented at:
• International Cycling Safety Conference 2021, Lund, Sweden (online)
• Tennessee Department of Transportation (TDOT) Innovation to Implementation Forum 2021

Links:
80% of fatal e-scooter crashes involve cars – new study reveals where and why most collisions occur, The Conversation
New Study Addresses E-Scooter Safety, UTK News

The Safer Scooting Study

This project is a partnership between faculty at Queensland University of Technology (Dr. Haworth) and University of Tennessee (Dr. Cherry) and industry partners Bird Scooter company is funded by the Australian Research Council (ARC). This three-year project aims to provide an understanding of how and why people use e-scooters and how rider behavior and safety outcomes change with experience. The anticipated goal of this project is to harness the potential benefits of e-scooters as an efficient replacement for short car trips and a way of improving access to public transport, while minimizing the dangers to riders and pedestrians. This knowledge is expected to inform governments at all levels, industry and riders on how to optimize e-scooter design, use and regulation to contribute to improvements in transport, health and environmental outcomes for all Australians.

E-Scooter Safety: Issues and Solutions

LEVER affiliates Laura Sandt and Katie Harmon (UNC) and Chris Cherry (UTK) and outside consultants (Dr. Sanders, Dr. Brown) and Populus (Clewlow and Seki) joined on this 30 month project to assess rider behavior issues associated with scooter use. E-scooters offer many potential benefits, including reduced air pollution in comparison to competing forms of transportation, first and last mile connections to public transit, increased mobility options, and new revenue sources for cities.  Recently, however, there has been a growing concern with injuries associated with e-scooter use. The objective of this research is to identify emerging behavioral safety issues arising from the expanding use of e-scooters, both rental and privately owned, and develop comprehensive guidance to help affected agencies plan for and mitigate related safety problems. The guidance should include tools, policy alternatives, educational materials, institutional requirements, and other relevant techniques to mitigate if not eliminate identified risks.

Links:
https://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4793

Sustainable Urban Mobility in Asia-Environmental Impacts of Electric Bikes-Clean Air

This study quantifies some of the impacts of the environmental impacts of the production processes and use phase of electric two-wheelers and compares them to the environmental impacts of the production processes and use phase of electric two-wheelers and compares them to the environmental impacts of competing modes, including bicycle, buses, motorcycles and cars. The biggest environmental reservation associated with electric bike is lead (Pb) pollution. This study discusses emission from the production processes, lead losses, and use phases of the electric bike and its alternative. The study found that the electric two-wheelers emit several times lower pollution per kilometer than motorcycle and cars, have comparable emission rates to buses and higher emission rates than bicycle.

Publication:
Comparative environmental impacts of electric bikes in China, Transportation Research Pard D.

Links:
Citation

Comparing safety related behavior between bicycles and electric bikes

The work was funded in part by the University of Tennessee, Knoxville, the Tennessee Department of Transportation, and the Southeastern Transportation Center. As suggested by the title this study develop a novel approach to safety behaviors analysis using naturalistic GPS data to evaluate the safety between regular bicycle and e-bike riders in context of a unique bike-sharing system. The study explored driving direction, speed and stopping behaviors of the users and found similar behavioral trend between both bicycle and e-bike riders. Similarly, the study also found that the users of both the technology had high violation rates of traffic control devices and suggests for some interventions to improve compliance.

Publication:
Risky riding: naturalistic methods comparing safety behaviors from conventional bicycle riders and electric bike users.

Links:
Project

Assessing sustainability impacts of shared e-scooters

This study proposes a framework to implement standardized micromobility data, such as Mobility Data Specification (MDS), to evaluate the energy and emission impacts of the shared e-scooters related to system operations and modal shift. The proposed methodology complements the existing studies evaluating the emission of shared e-scooter systems by estimating the usage and operational parameter of the Life Cycle Assessment (LCA) using Big Data. Along with improving the accuracy of the LCA analysis, such an approach also allows the evaluation of the temporal aspect of emission and energy use profile (such as time-of-the-day, day-of-the-week, and month-of-the-year). The findings of the proposed analysis are expected to help city governments to understand the overall environmental impact of shared e-scooters and develop data-driven strategies to manage their transportation-related sustainability impacts. This project is funded by the Oak Ridge National Laboratory’s (ORNL) Graduate Advancement, Training, and Education (GATE) program.

Links:
Fellowship award

THRUST 3: HEALTH IMPACTS FROM E-BIKE USE

Some types of e-bikes provide moderate physical activity (PA) to riders and are a form of active transportation (AT) that can improve health outcomes for riders. E-bikes provide less AT PA than cycling, but could help riders maintain longer term and higher volumes of PA over time because e-bikes do not require vigor ous activity as traditional bicycles. The health industry is interested in assessing e-bikes as a technology to increase and maintain PA, particularly among sedentary adults. In addition, users of e-bikes and other LEVs are exposed to air pollution during travel. As with other modes of transportation, this exposure can have impact on the user’s health. The relative benefits of these modes on user health, considering PA benefits and other factors, are important research questions. This theme will explore the crossing themes of improved health outcomes from higher physical activity, countered by increased exposure to urban roadside air pollution compared to car driving and traditional cycling.

Health Impacts of Emission from Electric and Traditional Motorized Transportation Modes in China

The study compared the emissions and environmental health impacts from the use of conventional vehicles and electric vehicles in 34 major cities in China. The study focusses on electric cars, electric two-wheelers including electric bicycles and light electric scooters in China. The study follows a conventional risk assessment framework and is based on pollutant intake. The study estimated exposure from emissions generated at more than 100 fossil EGUs. The study employed point estimates for input parameters and conducted Monte Carlo simulation to identify the sensitivity. The study also illustrated an example of the policy significance of the research by considering a deployment scenario for Shanghai. The findings highlight the importance of considering exposures, and especially the proximity of emission to people, when evaluating environmental health impacts for EVs.

Publications:
Electric Vehicle in China: emission and health impacts.
Environmental Justice Aspects of Exposure to PM2.5 Emissions from Electric Vehicle Use in China

Links:
Project

Comparing Physical Activity of E-bikes, Bicycling, and Walking

In one of the first measured e-bike physical activity studies, LEVER researchers Cherry, Bassett, Fitzhugh, and Langford (UTK) assessed and compared the metabolic activity generated by riding a pedal assist e-bike, a conventional bicycle, and walking along a fixed course with downhill, flat, and uphill sections. They estimated energy expenditure based on heart rate and ventilation rates (VO2). They found that e-bikes provide moderate physical activity (MET>3) on flat segments and downhill segments, and vigorous physical activity (MET>6) on uphill segments. Differences between e-bikes and bicycles are most pronounced on the uphill segment. For e-bike trials, riders reported higher levels of enjoyment and lower need for a shower than walk or conventional bicycle trials. E-bikes can contribute as an active transportation mode to meet required physical activity guidelines. This work was funded by the Southeastern Transportation Center and the Institute for a Secure and Sustainable Environment.

Publications:
https://www.sciencedirect.com/science/article/pii/S2214140516303930

Compared Physical Activity of E-scooters, Walking, and Driving

Following on their e-bike physical activity work, LEVER researchers Cherry, Wen, and Bassett are setting out to identify the level of physical activity of e-scooter users. They followed a similar approach to their earlier e-bike study. Here, they directly measure ventilation rates (using a Cosmed Fitmate) while riding a scooter, walking and driving the same course as the previous study. In addition, they conducted a fixed-maneuver trial of muscle activity on each mode using an EMG device, assessing activity of 15 muscle groups. As expected, scooter riding metabolic activity seems to fall between walking and driving. Upper limb and trunk muscle groups are higher for scooter riding than other modes.

Publications:
https://onlinepubs.trb.org/onlinepubs/conferences/2019/CHAT/Agenda.pdf

THRUST 4: URBAN FREIGHT LOGISTICS

Freight system supply chains are generally very efficient at moving large quantities of goods between distribution centers. The “last mile” of the freight system requires a disproportionate amount of resources and has a large impact on environmental and economic performance, particularly in dense urban areas. LEVs provide an opportunity to provide distributed and high performing (cost, effectiveness, and environment) technology for urban freight delivery. This theme will investigate new distribution models enabled by LEVs that can improve the operational and environmental performance of urban freight logistics systems.

Alternative Vehicles for Last Mile Freight

Micromobility vehicles have the potential to transform urban freight delivery. E-bikes and e-trikes are part of the e-cargo landscape. This research addresses alternative vehicle use for last mile freight by LEVER researchers Cherry, Azad, Rose, and Autry (UTK) and MacArthur (PSU) with industry partner B-Line in Portland. To overcome the limitation in data availability GPS data were collected during October and November 2017. We constructed two simulations to evaluate the costs of the system and estimate the costs if the company utilized vans (all or a mixed fleet) for deliveries for the same e-bike delivery company and a test case in Nashville. Overall, the associated total costs of a LEV-based delivery system are not dramatically higher than traditional systems. Availability of bike infrastructure, location of distributing center, and density of delivery area are important factors that contribute in competitiveness of a LEV delivery company. This work was funded by Tennessee DOT.

Publication:
Alternative Vehicles for Last Mile Freight

THRUST 5: SHARED LEVS

The sharing economy in transportation is emerging alongside the development of advanced LEVs. In many ways, synergies between LEVs and sharing technology can create opportunities for increasing the LEV market, exposing more users to LEVs, and providing appropriate technology (LEVs) for many of the urban trip patterns that occur in shared vehicle systems. LEVs provide unique challenges and opportunities in shared vehicle environments. This research thrust will focus on identifying the role of LEVs in shared vehicle systems.

Electric Bike Sharing-Evaluation of System Impacts

This published work presents the first-year operational experience of CycleUshare, an e-bike sharing system in the campus of the University of Tennessee Knoxville that combined the bike-sharing with e-bike. The CycleUshare is the North America’s first e-bike-sharing system that offered a sustainable transportation option for students, faculty, and staff. The CycleUshare system had two stations and was launched as a small pilot project to study the technology and its users’ experiences. The data for the analysis was based on the transaction log, GPS data, and survey questioner. The published work provides insights into the system’s users and trip characteristics during the first year of operations. Moreover, the program has provided an educational platform to introduce alternative modes of transportation and alternative vehicle technologies to thousands of students and staff.

Publication:
North America’s first electric bicycle share: A year of experience. Transportation Research Record: Journal of the Transportation Research Board

Links:
Project

Big data analytics to assess travel behavior of shared micromobility use

Identifying shared e-scooter trip patterns

Using Big Data and Machine learning approaches, we proposed a framework for high-resolution analyzing micromobility data based on temporal, spatial, and weather attributes. This study scrutinized over a million e-scooter trips in Nashville, Tennessee to identify five distinct usage patterns over the study period. They are morning work/school, daytime short errand, social, nighttime entertainment district, and utilitarian trips. Among other findings, the most common use of e-scooters in Nashville was daytime short errand trips, contributing to 29% of all e-scooter trips. Only 16% of trips were nighttime entertainment district-related trips. Understanding when and where people use e-scooters can help city governments make data-driven decisions regarding safety, sustainability, and mode substitution of emerging micromobility.

Links:
Best Paper Award at: Tennessee Section of Institute for Transportation Engineers (TSITE)
Second Place at: Southern District Institute of Transportation Engineers (SDITE) paper competition

Estimating demand elasticities of shared e-scooters.

We estimated the demand elasticity of deployed e-scooter vehicles by comparing actual demand (e-scooter usage) with supply dimensions (vehicles deployed). The study used almost a year-long geographically disaggregated e-scooter trip summary data and location of available e-scooters that updates approximately every five minutes from Nashville, Tennessee. We found that the demand for e-scooter vehicle deployment is inelastic, suggesting e-scooter trips increase at a lower rate than the increase in e-scooter vehicles deployed. The service providers with large fleet sizes (>500) have a demand elasticity of e-scooter deployment that is 1.4 times higher than that of medium fleet-sized service providers (250-500) and 3.5 times higher than that of small fleet-sized service providers (<250). These findings could be helpful for city governments to me identify the optimal number of service providers and fleet sizes to permit so that demand is fulfilled without an oversupply of e-scooter vehicles in public spaces.

Publication:
Presented at:
• Transportation Research Board 101st Annual Meeting 2021, Washington, D.C.

Bikeshare and E-bikeshare travel preferences in China

The rapid growth in personal e-bike ownership brings both benefits and costs similarly arise concerns about safety, disruption to traffic, and environmental impacts of such vehicles. The paper conducted a choice experiment for conventional and electric bike-share in Beijing, China. The study employed a stated preferred survey and multinomial logit mode switching model to estimate the factors influencing the choice to switch from an existing transportation model to bike-share or e-bike-share choices. The study found that the bike-share choice is most sensitive to measures of effort and comfort for the given population, while the e-bike share choice is more sensitive to user heterogeneities. The study also found that the travelers are not particularly concerned with uncomfortable temperature and air quality conditions if trip link distances are small. The result demonstrate that e-bike share may be strongly preferred to bike-share by young to middle-aged respondents with diminishing advantage until age 69.

Publication:
Factor influencing the Choices of Public Shared Bicycles and Electric Bicycling in Beijing, Transportation Research Record Part C.

Links:
Project