Content uploaded by Oliver Carsten
Author content
All content in this area was uploaded by Oliver Carsten on Jan 19, 2021
Content may be subject to copyright.
Vulnerable Road Users: How Can
Automated Vehicle Systems Help to Keep
Them Safe and Mobile?
Alma Siulagi, Jonathan F. Antin, Lisa J. Molnar, Sue Bai,
Seleta Reynolds, Oliver Carsten and Ryan Greene-Roesel
Abstract For the first time in 2015, the Automated Vehicle Symposium featured a
breakout session explicitly devoted to vulnerable road users (VRUs) and their use
of and interactions with automated vehicles. A number of stakeholders, experts, and
researchers from a variety of fields presented and discussed the state of current
research and thought concerning the potential relationship of vulnerable road users
A. Siulagi
Design City and Regional Planning, University of Pennsylvania,
4635 Sansom St. #2, Philadelphia, USA
e-mail: siulagia@design.upenn.edu
J.F. Antin (&)
Virginia Tech Transportation Institute, 3500 Transportation Research Drive,
Blacksburg, VA 24060-0536, USA
e-mail: jantin@vtti.vt.edu
L.J. Molnar
University of Michigan Transportation Research Institute, 2901 Baxter Road,
Ann Arbor, MI 48109-2150, USA
e-mail: ljmolnar@umich.edu
S. Bai
Honda R & D Americas, Inc., 1000 Town Center Dr., Ste 2400,
Southfield, MI 48075, USA
e-mail: SBai@oh.hra.com
S. Reynolds
Los Angeles Department of Transportation, 100 S Main Street, 10th Floor,
Los Angeles, CA 90012, USA
e-mail: seleta.reynolds@lacity.org
O. Carsten
Institute for Transport Studies, Leeds LS2 9JT, UK
e-mail: o.m.j.carsten@its.leeds.ac.uk
R. Greene-Roesel
San Francisco County Transportation Authority, 1455 Market Street, 22nd Floor, San
Francisco 94103, USA
e-mail: ryan@sfcta.org
©Springer International Publishing Switzerland 2016
G. Meyer and S. Beiker (eds.), Road Vehicle Automation 3,
Lecture Notes in Mobility, DOI 10.1007/978-3-319-40503-2_22
277
and automated vehicles and how to maximize the benefits this novel technology
might bring to these individuals. The topics included the role of design, various
technological solutions, policies, and programs that could advance the safe mobility
of VRUs in a future with an integrated fleet of automated vehicle systems. Through
expert-led small group discussion, the breakout group produced a list of possible
definitions for VRUs including pedestrians, cyclists, seniors (pedestrians as well as
drivers), and identified key research gaps within the context of this multifaceted
segment of the population. Some of these gaps related to motorcycle interactions,
how different groups of VRUs will accept emerging AV technologies, and goals
and solutions when considering how best to share limited roadway space across all
road user constituencies.
Keywords Aging drivers Pedestrians Bicyclists Automated/autonomous
surface vehicles Automated vehicle symposium Vulnerable road users
Connected technologies Automated rules following Unintended consequences
Privacy concerns Trafficflow Holistic inclusive platform Vision zero Road
sharing
1 Introduction
As automated features begin to permeate the market and the possibility of partial
and one-day full automation becomes more likely, it is essential to both review
possible impacts on traditionally vulnerable populations as well as reimagine vul-
nerability under this emerging market.
The breakout session, “Vulnerable Road Users: How Can Automated Vehicle
Systems Keep them Safe and Mobile?”held at the Automated Vehicles Symposium
2015 in Ann Arbor, Michigan attempted to explicitly address these pressing
questions for the first time at the AV symposium series. The 3-h session aimed to
define vulnerable road users (VRUs) within the context of automated vehicles
(AVs); to identify critical research gaps; and to determine whether the topic of
VRUs was suited for future Automated Vehicle Symposium breakout sessions.
Experts from across sectors and disciplines took turns presenting. Then, an
open-ended discussion was held with the moderator, speakers, and audience
members participating vigorously. Together, the session’s experts and participants
produced a list of possible definitions of VRUs, a list of research gaps, and agreed
on the importance of continuing the conversation in the coming years.
Following is a synthesis of the perspectives of the expert presentations, a brief
analysis of the benefits and challenges identified in the presentations, a review of
the insights from the panel and small group discussion, and the results of the
session, including a list of possible definitions and critical research gaps. The
information, analysis, products, and conclusions from this breakout session provide
a much-needed baseline for future discussions centered on AVs or VRUs.
278 A. Siulagi et al.
The term “vulnerable road users”has traditionally been limited to pedestrians,
bicyclist, and motor cyclists because these groups are considered to be at the
highest risk in traffic due to their lack of external protection [1]. However, in recent
years, it has been argued that older drivers also fall into this category because of
their increased fragility and frailty which make them more susceptible to injury and
death in the event of a crash [2]. Efforts to reduce injuries and deaths among
vulnerable road users have been multifaceted and include improvements in roadway
infrastructure, education and training relative to road user behavior, implementation
of policies and regulations such as helmet laws, and advances in vehicle design [3,
4]. Recent advances in automated vehicle technology also show promise for
enhancing the safety of all road users, including vulnerable road users. However,
these technologies are still early in their development and important questions
remain about their effectiveness in enhancing the safety and mobility of vulnerable
road users, and how they might be used and accepted by these populations.
2 Issues and Solutions
The presentations in the breakout session represented a wide variety of experts and
perspectives of those working on projects reaching across sectors, disciplines, and
the globe. The diversity of perspectives also meant a wide range of definitions of
who qualified as a VRU—the presentations mentioned bicyclists, pedestrians, older
drivers, and urban populations as possibly vulnerable within an AV context. Each
presentation touched upon current projects, possible benefits, challenges, and future
steps forward.
2.1 The Presentation Summaries
2.1.1 Vehicle-Smartphone Communication to Protect Road Users
(V2P and Beyond) Presented
1
Ms. Bai presented current research scenarios being conducted by Honda and
Qualcomm that explore how connected vehicle technology could extend to
pedestrians, bicyclists, and other VRUs via smartphone technology. This would
address pedestrian (and other VRU) deaths and their societal cost. However, it will
require cooperation between automotive manufacturers and the wireless industry to
develop the standards necessary for wider production. Ms. Bai stated that this
technology will be tested as a pilot program on a campus in the near future. Possible
1
Presented by Sue Bai, Principal Engineer, Automobile and Technology Research Department,
Honda R&D America, Inc.
Vulnerable Road Users: How Can Automated Vehicle Systems …279
limitations included identifying relevant pedestrians to vehicles, sudden crossing
maneuvers, positional accuracy, positional data in parking structures, smartphone
battery power, and communication channel congestion.
2.1.2 How Can We Use AVs to Protect VRUs?
2
Dr. Van Houten presented common risk and crash scenarios for pedestrians and
bicyclists that AV systems would be able to address by simply automatically fol-
lowing the rules currently in place (which human drivers may or may not follow).
He offered the example where at a stoplight a human driver might pull forward past
the stop bar, whereas an AV could be programmed to stop appropriately behind the
line, thus keeping crossing VRUs safer. Dr. Van Houten also mentioned personal
GPS transponders as a possible way for bicycles, pedestrians, and cars to com-
municate to prevent accidents. However, he expressed concerns that these solutions
also had possible negative effects which would need to be addressed: privacy,
possible negative influences on trafficflow, and dependence on smartphone tech-
nology (as per Ms. Bai’s presentation) among them.
2.1.3 Automated Vehicle Symposium Vulnerable Users
3
Ms. Reynolds presented a way for cities to approach the oncoming changes in
transportation, with AVs as one of many possibly “disruptive”forces. She outlined
a role for the city in promoting the outcomes best for their urban populations at
large, in particular safety and efficient mobility. Ms. Reynolds asserted that cities
are still learning to be start-ups and can leverage their strength in street design and
managing mobility by integrating modes into a holistic and inclusive user platform.
Cities may not provide the technology platforms for new mobility, but they should
lead the policy and regulatory agenda with these top level outcomes in mind. She
stressed the need for city representatives to be engaged early in such conversations
regarding possible urban transportation futures. In terms of AVs, Ms. Reynolds
mentioned two possible outcomes: the “robo-taxi pod car”and the “luxury long
commute”model of AV deployment, asking cities and their leaders to investigate
which model would bring cities closer to vision zero goals. She mentioned that the
repurposing of roadway space can generate powerful backlash and need strong
partnerships in both the public and private sphere to determine outcomes.
2
Presented by Ron Van Houten, Ph.D., Professor of Psychology, Western Michigan University.
3
Presented by Seleta Reynolds, General Manager, Los Angeles Department of Transportation.
280 A. Siulagi et al.
2.1.4 Implications of Automated Vehicles for Older Drivers
Dr. Molnar presented her research on how AVs may affect older drivers. She noted
that older drivers in the US, like other age groups, prefer to travel by personal
vehicle but may experience age-related declines in visual, psychomotor, and cog-
nitive abilities that can compromise safe driving. Thus, the emergence of AVs may
be a great boon for aging drivers, allowing them to maintain mobility while
reducing their risk of crashes. At the same time, Dr. Molnar noted that older drivers
may face special challenges in using and benefiting from AVs. She discussed
several of these challenges and highlighted the importance of making sure that AV
design is responsive to the needs and preferences of older adults. She emphasized
that design features such as smart headlights, reverse monitoring systems, assistive
parking systems, and lane departure warnings work best for older drivers.
2.1.5 Automation Connection and Cyclists
4
Dr. Carsten presented on his work on bicyclists as VRUs and the challenge of
accommodating them in AV design. He outlined common bicycle conflicts with
cars and their unique modal characteristics that make them difficult to design for,
such as their speed relative to prevailing motorized traffic and tendency to violate
traffic rules. Dr. Carsten showcased the XCYCLE program, which reviews how
connected vehicle technology can promote cyclist safety via passive, two-way, or
active detection systems. The central question remains how the connection can be
imposed on cyclists.
2.2 Summarizing Proposed Solutions to Accommodate
VRUs Within an AV Context
These five experts presented the state of research, programs, and pilots currently
addressing the complexities associated with AVs in the context of servicing or
interacting with VRUs. Table 1organizes the solutions touched in in presentation
into four general categories: AV design, additional technologies, environmental
design, and programs and policies. Some solutions are combined with others. For
each solution, a goal is presented, as well as the limitations and steps forward that
the presentations discussed. Many of these issues are discussed more thoroughly in
the section summarizing the panel and small group discussion.
4
Presented by Oliver Carsten, Ph.D., Professor of Transport Safety at the Institute for Transport
Studies, University of Leeds.
Vulnerable Road Users: How Can Automated Vehicle Systems …281
Table 1 Summary of the approaches to accommodate VRUs within an AV context
Proposed
solutions
Presenter Goal Limitations Steps forward
AV design
Automated
warning system
paired with
pedestrian
detection system
Bai To reduce the risk
of injury or fatal
pedestrian injuries
Possible disruption
to trafficflow
Honda and
Qualcomm
campus pilot
Designing AVs
to follow existing
traffic rules
(speed, roadway
markings)
Van
Houten,
Carsten
To reduce the risk
of injury or fatal
pedestrian injuries
Public acceptance,
as many drivers
today consistently
choose not to obey
may traffic laws
and regulations
Designing an
elderly friendly
AV user interface
for seniors AVs
Molnar To reduce the risk
of distraction for
older drivers
May not be
desirable if
marketed as being
an “older driver”
vehicle or feature
Suggested further
research
Additional technologies
Pedestrian
detection systems
using either GPS
transponders,
smartphone
technology, or
connected
technologies
Van
Houten,
Bai,
Carsten
To reduce the risk
of injury or fatal
pedestrian injuries
Privacy,
dependence on
smartphone
technology
Honda and
Qualcomm
campus pilot;
XCYCLE
program (H2020
smart green and
integrated
transport)
User interface
integrated across
all available
modes
Reynolds To increase
mobility options
for urban residents
and move towards
transportation as a
utility
Not discussed
Environmental design
Redesign
infrastructure and
roadways to
accommodate
modes differently
Reynolds To reduce the risk
of injury or fatal
pedestrian injuries
on previously
identified
dangerous streets
Lack of public
acceptance;
concern about loss
of private parking
(continued)
282 A. Siulagi et al.
3 Issues and Current Thought
The questions addressed in the panel and the small group discussions identify
important issues with current thought surrounding AVs and VRUs. A brief sum-
mary of each is presented below to stimulate discussion and broaden the scope of
the issue beyond expert presentations.
3.1 Review of the Panel Session
In the panel session, participants asked a wide range of questions that focused on
proposals to alter roadway design, the Honda-Qualcomm pilot project, and ways to
design programs and policies that could achieve preferred safety outcomes.
Following up on Ms. Reynolds and Dr. Van Houten’s presentations, participants
questioned how contemporary roadway infrastructure would interact with AVs and
VRUs. Particularly, one audience member raised an issue that has been debated
previously in AV circles: would AVs be programmed to recognize and obey speed
limits? This would bring certain benefits to pedestrian and bicyclists and perhaps
other VRUs. While Dr. Carsten took the line that lowering speed is a basic safety
principle and that AVs should not allow excessive speeding, Ms. Reynolds pointed
out that how we set speed limits is a historical process already divorced from both
current safety realities and possible AV futures. In this case, it would seem that the
Table 1 (continued)
Proposed
solutions
Presenter Goal Limitations Steps forward
Programs and policies
Cities as key
policy-makers in
decisions that
may disrupt the
transportation
system
Reynolds To enable cities to
achieve triple
bottom line
outcomes for urban
residents around
safety, mobility,
sustainability, and
resilience
Cities wield
limited power and
must leverage
outcomes to
achieve desired or
required levels of
efficiency
Cities getting
involved in and
establishing role in
decision-making
conversations
concerning urban
transportation
systems’futures
Technology
adoption program
tailored to older
adults
Molnar To increase the
quality of life for
aging drivers by
increasing their
willingness to
engage with novel
emerging
technologies
Not discussed Suggested further
research
Vulnerable Road Users: How Can Automated Vehicle Systems …283
contemporary traffic safety infrastructure should be reconsidered within current and
possible future contexts including automation.
Another audience member followed up with a question about Ms. Reynold’s
proposal to redesign streets to accommodate non-motorized modes and how
devoting more road space to bicycles and pedestrians might influence congestion
and throughput for vehicles. Ms. Reynolds supplied Portland, Oregon and San
Francisco as examples of cities that have dedicated significant lane space to bicy-
clists without degrading throughput. She explained that in corridors with congested
vehicle traffic, cities and decision-makers should aim to draw drivers into other
modes rather than jumping immediately to increasing capacity for vehicles.
A second group of participant questions focused on the Honda /Qualcomm pilot
for smartphone pedestrian detection systems. One questioned how the system
design would respond to irrational users, such as pedestrians who do not pay
attention or cyclists who take safety risks. All of the panel members agreed that
there is no known way to design for this, and that while that question has yet to be
answered, the system should be forgiving of all behavior. A panel member sug-
gested that if pedestrians could cross where they liked without the risk of injury,
this would change much for populations such as the blind.
Other participants questioned whether smartphones were the right technology to
support pedestrian and bicyclist detection systems. Access to smartphones, the
unreliability of smartphones (e.g., battery life), and the suitability of the interface to
relaying critical and immediate safety information were raised as potential system
failures.
Participants also expressed concerns about inducing safety outcomes both at the
urban and subpopulation level. Ms. Reynolds discussed the “vision zero”strategy
adopted by five cities in California, and their different approaches to creating safer
streets, including identifying the most important crash sites and streets, looking for
patterns amongst crash data, and re-conceptualizing project delivery, partnerships,
and the role of the citizen. Dr. Van Houten pointed out that in the case of requiring
AVs to obey traffic safety laws, safety outcomes are built into AVs. Two other
participants wondered how children’s safety would work in an AV future, and how
the benefits could be maximized for the elderly despite their tendency towards slow
adoption of technology.
3.2 Questions for Further Discussion
Due to the size of the audience, small group discussion was conducted as a single
group in a less formal manner than the panel-audience set up. Dr. Antin began by
reading the discussion questions the breakout session:
•Who are the key vulnerable road users that could be affected by AV technology?
•What are the unique needs of each VRU group?
•How might each group benefit from AV technology?
284 A. Siulagi et al.
•Do AVs pose any risks to VRUs?
•What are key research gaps in exploring the relationships between VRUs and
AV technology?
These questions framed the results presented below in Table 2. However, the
small group discussion included ideas for the future of VRUs as a topic of focus at
AVS.
3.3 The Future of VRUs at AVS
Participants reviewed whether VRUs should be included as an ongoing topic at
AVS considering its new place on the program and relatively low turnout. While
many felt the session was important, others suggested that it could be merged with
the popular, two-day human factors session. This would mean VRUs could gain a
wider audience and consider breaking out into its own session in later years.
4 Results
One of the key topics of discussion was who (or what transportation modes)
qualified as VRUs? Different ideas were discussed; these are presented in Table 2.
The questions addressed in the panel and the small group discussions identify
important issues with current thought surrounding AVs and VRUs. A brief sum-
mary of each is presented below to stimulate discussion and broaden the scope of
the issue beyond expert presentations.
Table 2 VRU candidates and qualifications
VRU candidates Qualification
Pedestrians Physical vulnerability and intersecting or shared right-of-way
with vehicles
Bicyclists Physical vulnerability and intersecting or shared right-of-way
with vehicles
Motorcyclists, scooters,
electric bikes
Physical vulnerability and intersecting or shared right-of-way
with vehicles; however they present additional challenges such
as white-lining behavior
Skateboarders, Segway
riders
Physical vulnerability and intersecting or shared right-of-way
with vehicles
Seniors Physical vulnerability and prone to cause more collisions
Disabled Depends on the particular disability (e.g., slower as a pedestrian,
deafness, or blindness)
Vulnerable Road Users: How Can Automated Vehicle Systems …285
•How do motorcycles mesh and interact with automated vehicle functions?
•How do we define what constitutes a VRU and is it fundamentally one group or
many with varying needs and concerns for each?
•How will the various VRU constituents accept emerging AV technologies?
•What are the goals and solutions when considering how best to share limited
roadway space (e.g., goals may include safety, fairness, costs, protecting the
environment, space livability, etc.)?
•How can AV technologies facilitate safe mobility for senior drivers, and what
are the hurdles that must be overcome when considering this growing segment
of our population within this context?
5 Discussion and Conclusions
This breakout session was noteworthy for three reasons. First, this was the first
formal breakout session at the annual Automated Vehicle Symposium devoted
explicitly to the needs and concerns of VRU. Second, it brought together
decision-makers and researchers across a broad spectrum who may not have pre-
viously communicated or discussed common issues surrounding VRUs from their
unique perspectives. And lastly, this represents the first attempt to begin an
ongoing, cross-sectoral conversation that defines VRUs in an ever-evolving AV
context.
References
1. Organization for Economic Co-Operation and Development, Safety of Vulnerable Road Users,
DSTI/DOT/RTR/RS7(98)/FINAL, Organization for Economic Co-Operation and Development,
1998
2. McMahon K (2008) Vulnerable road user safety: children, elderly road users and pedestrians.
International Transport Forum, Joint Transport Research Centre, Paris, France, 2008
3. Constant A, Lagarde E (2010) Protecting vulnerable road users from injury. PLoS Med 7(2):1–4
4. Goodwin A, Kirley B, Sandt L, Hall W, Thomas L, O’Brian N, Summerlin D (2013)
Countermeasures that work –a highway safety countermeasure guide for state highway safety
offices, 7th edn. University of North Carolina Highway Safety Research Center
286 A. Siulagi et al.
