PUBLIC ROADS

www.fhwa.dot.gov Spring 2021

MICROMOBILITY

A TRAVEL MODE INNOVATION

Also in this issue: 

Collaborating for Pedestrian Safety 

Nondestructive Evaluation of 

Post-Tensioned Bridges 

Using Unmanned Aerial Systems to 

Collect Better Geotechnical Data
Spring 2021 | Vol. 85, No. 1

Micromobility: A Travel Mode Innovation 

PAGE 8

FEATURES

4 CARMASM: Improving Traffic Flows and 

Safety at Active Work Zones

by Pavle Bujanović, Todd Peterson, and Denise Bakar

FHWA’s CARMASM Program is testing how cooperative driving 

automation can manage work zone congestion and enhance safety.

8 Micromobility: A Travel Mode Innovation

by Jeff Price, Danielle Blackshear, Wesley Blount, Jr., and Laura Sandt

With increased growth in bikeshare and shared e-scooter 

systems, FHWA and USDOT are helping State DOTs and 

cities manage micromobility deployment, and are monitoring 

trends and evaluating facilities and design needs.

13 Focusing on Pedestrian Safety

by Tamara Redmon, Ann Do, Rebecca T. Crowe, Darren Buck, and Michael S. Griffith

FHWA and other agencies across USDOT are continually addressing 

safety concerns for pedestrians by developing and researching effective 

tools and countermeasures and by coordinating projects, plans, 

and discussions with State and local officials and safety advocates.

19 Looking to the Sky for Geotechnical Data

by Derrick Dasenbrock, James Gray, Ben Rivers, Ty Ortiz, Jody Kuhne, 

and Krystle Pelham

States are using data from unmanned aerial systems to help predict 

geological threats, prioritize mitigation efforts, and aid recovery 

after an event occurs—with reduced costs and improved safety. 

25 Magnetic Flux Methods: Detecting Corrosion in

Post-tensioned Bridges

by Hoda Azari and Seung-Kyoung Lee

FHWA developed and evaluated a proof-of-concept prototype for 

the magnetic-based, nondestructive evaluation technique called 

the return flux method. Laboratory test results prove encouraging 

in identifying corrosion damage in post-tensioned bridges.

PAGE 19 

© University of Vermont Spatial Analysis Lab.

DEPARTMENTS

Guest Editorial ..................................................1

What’s New......................................................2

Innovation Corner ...........................................3

Along the Road ..............................................28

Training Update .............................................30

Internet Watch ..............................................32

Communication Product Updates ..............33

COVERS and ABOVE—Emerging micromobility options, 

like shared e-scooter programs, offer riders new 

options for shorter trips and active transportation.

© Oleg Elkov / iStock.com.
WWW.FHWA.DOT.GOV | 1

U.S. Department of Transportation 

Federal Highway Administration

U.S. Department of Transportation

Pete Buttigieg, Secretary

Federal Highway Administration

Stephanie Pollack, Acting Administrator

Office of Research, Development, and Technology

Kelly Regal, Associate Administrator 

Shana Baker, Director, Office of Corporate Research, 

Technology, and Innovation Management

Maria Romstedt, Editor-in-Chief

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Editorial Board: 

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G. Shepherd, C. Walker 

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Georgetown Pike, McLean, VA 22101-2296. The business and 

editorial office of Public Roads is located at the McLean address 

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-

GUEST EDITORIAL

Working Together 

to Improve 

Pedestrian Safety

© New Hampshire Department 

of Transportation.

I

n 2019, traffic deaths decreased across the 

United States, with a fatality rate of 1.10 per 

100 million vehicle miles traveled, the lowest 

since 2014. This is positive news, but even 

more encouraging is the 2.7-percent decrease 

in the number of pedestrian fatalities.

To lose 36,096 individuals on our Nation’s 

roads, including 6,205 pedestrians, is still 

unacceptable, but given that there was a 

3-percent increase in pedestrian deaths in 2018 

and a 53-percent increase from the low point in 2009 until 2018, any reduction in 

pedestrian fatalities shows that efforts to improve safety may be starting to pay off. 

As with any roadway safety challenge, it takes numerous stakeholders all doing 

their parts to bring results. Roadway designers, vehicle manufacturers, law enforce

ment, and the public all have a role to play.

-

One of the innovations in round 5 of the Federal Highway Administration’s 

Every Day Counts initiative was Safe Transportation for Every Pedestrian (STEP). 

This innovation encouraged States and municipalities to continue to deploy proven 

safety countermeasures, such as rectangular rapid flashing beacons, crosswalk 

visibility enhancements, pedestrian hybrid beacons, and road diets. Many of these 

countermeasures not only improve safety, but have the added benefit of enhancing 

quality of life for pedestrians of all ages and all abilities at a relatively low cost. As 

transportation departments across the country continue to focus on pedestrian 

crossing locations in a systematic way, it is anticipated that there will be even greater 

reductions in pedestrian deaths.

The increase in the percentage of sport utility vehicles on roadways is undoubt

edly one cause of the increase in pedestrian fatalities from 2009 onward. Vehicle 

manufacturers have been working to modify the design of vehicles to reduce the 

severity of crashes, despite vehicle owners continuing to favor large vehicles, which 

commonly pose a greater risk to pedestrians than smaller vehicles. Deploying 

technologies such as pedestrian crash avoidance systems is one of the most prom

ising solutions to reduce the hazard for pedestrians. Vehicles equipped with these 

technologies either stop in time to prevent a pedestrian crash or slow down signifi

cantly to reduce the severity of the impact. As the deployment of these technologies 

expands and the technologies are refined, it will certainly lead to positive outcomes.

-

-

-

For our law enforcement personnel, training has been developed to help officers 

understand the factors associated with pedestrian crashes. The National Highway 

Traffic Safety Administration offers training that provides suggested enforcement 

strategies, but also addresses the importance of complete and accurate crash report

ing. Encouraging accurate crash reporting and publishing of data not only helps 

roadway designers prioritize investments, but also leads to greater citizen engage

ment and public awareness.

-

-

Which brings us to the public and pedestrians themselves. Having a shared 

understanding of where and how crashes are occurring is a critical first step. Human 

behavior is still a primary contributing factor for crashes, so all roadway users must 

acknowledge that safety is a shared responsibility. Whether behind the wheel of a 

vehicle, riding a bicycle, or walking, we all need to be aware of our surroundings, 

avoid distraction, and follow the rules of the road. 

Continuing to work together and all doing our part to enhance safety is the only 

way to move toward zero deaths on our Nation’s roadways.

Victoria F. Sheehan

Commissioner

New Hampshire 

Department of Transportation
2 | PUBLIC ROADS | SPRING 2021

© Kruck20 / iStock.com.

WHAT’S NEW

New Era, New Opportunities

by STEPHANIE POLLACK

Though I’ve only been with the Federal Highway Administration for a short time, it’s already clear what an exciting time 

the coming year will be at FHWA and the U.S. Department of 

Transportation because of the central role that these agencies will 

play in the Biden-Harris Administration’s “Build Back Better” 

agenda. With our local and State partners, FHWA will be critical 

in shaping how the Nation rebuilds highways, bridges, and streets 

to be better. Making sure they are safer for all users will be the 

foundation of a truly multimodal surface transportation system 

that advances the equity agenda of better connecting people 

to opportunity.

-

In my previous role as Secretary and CEO of the Massachusetts 

Department of Transportation, I grew to admire FHWA’s impor

tant work nationwide. In that role, I was probably best known 

for emphasizing that transportation is not important for what it 

is—for roads and bridges, concrete and steel, or even buses and 

trains—but for what it does. It helps people and their communities 

succeed and prosper.

-

Obviously, we are in the infrastructure business—but we are 

also in the people business. For example, while safety will always 

be our most important job, we need to make sure that we focus 

on everyone’s safety—drivers and passengers, of course, but also 

pedestrians, people in wheelchairs, cyclists, and transit passengers 

entering or leaving their station or stop. That’s why I am so excited 

about U.S. Transportation Secretary Pete Buttigieg’s embrace of 

complete streets, which are really just streets that are safe—and feel

safe—for all users. We did a lot of great work on building complete 

streets in Massachusetts and I know there’s more FHWA can do to 

ensure that streets everywhere are safe for everyone. To cite just one 

example, the pending changes to the Manual on Uniform Traffic 

Control Devices have the potential to empower local and State street 

owners to rethink how streets are signed, signaled, and marked, 

and how speed limits are set.

Complete streets are just one example of how the world of 

transportation is changing. By training, I am an engineer. By 

definition, engineers are problem solvers—but the problems we are 

asked to solve are changing. We cannot ensure that highways and 

bridges are well-maintained without making sure our infrastructure 

investments are succeeding in making transportation networks 

more reliable. We want to ensure those investments advance equity 

and help build a transportation system that works for everyone. We 

also want to ensure that those investments address climate change, 

and acknowledge that the transportation sector produces the larg

est and fastest growing set of greenhouse gas emissions.

-

As I see it, we have two problems to solve in addressing climate 

change. First, how to build out the infrastructure that will help 

decarbonize travel and, second, how to make transportation 

infrastructure resilient to a changing climate. With some of the 

world’s most innovative road and bridge engineering and planning 

expertise, and access to important and actionable data, FHWA is 

the perfect place to lead on solving this more broadly defined set of 

transportation challenges.

I look forward to helping to ensure that America has a 

21st-century transportation system that works for, and is safe for, 

everyone. This will be a new era with new opportunities for the 

agency and, together, we will continue to lead even as we face 

new challenges.

STEPHANIE POLLACK is FHWA’s Acting Administrator.
WWW.FHWA.DOT.GOV | 3

INNOVATION CORNER

From the Center for Accelerating Innovation

Have You Shared Your Innovation with Your Neighbor?

by JEFFREY ZAHAREWICZ

Sometimes the inspiration to try something innovative can come from your neighbor’s proverbial backyard. Creating a 

neighborhood for the transportation community to share their 

successes was the goal of the National State Transportation Inno

vation Council Network Showcase (STIC Showcase), conducted 

as part of the Virtual Summit that launched Every Day Counts 

round six (EDC-6; for more information, see the Innovation 

Corner in the Winter 2021 issue of Public Roads). 

-

The STIC Showcase provided a virtual venue to celebrate 245 

innovations developed and deployed across the country that save 

lives, time, and resources, and created a space for the innovations 

to find a wider audience to expand their use and impact. 

Sara Lowry, the STIC program coordinator at the Federal 

Highway Administration, described the call 

for ideas and ground rules for participation: 

“Working with each STIC, we solicited for 

innovations that were ‘homegrown,’ already 

successfully deployed, and could easily be 

adapted by other transportation agencies. We 

were truly excited by the response!”

Sharing Insights Virtually

Organized around topics such as safety, design 

and construction, and maintenance and emer

gency response, the STIC Showcase featured 

virtual posters that described each innovation 

and its benefits, along with access to support

ing resources and points of contact. Summit 

attendees could browse through these posters 

at their own pace, and download and share the 

information with peers.

-

-

Clare Fullerton, P.E., the manager for the 

North Carolina Department of Transpor

tation’s Communicate Lessons, Exchange, 

Advice, Record (CLEAR) Program, found 

immediate value with this technical content. 

“I have saved many submissions into my ‘briefcase’ so that I can view them at a later date,” 

she says. “As things come up in day-to-day 

work, I’ve gone back to the Showcase to see if 

another State has solved a similar issue.”

-

Indeed, attendees were able to compare efforts from around 

the country on a variety of topics. For example, visitors to the 

safety section could learn about the wrong-way driving initiatives 

from the Arizona and Florida DOTs. Elsewhere, the Indiana and 

Mississippi DOTs each shared their approaches to saving time by 

conducting risk-based contract administration and inspection.

Presenting Live Panels

To complement this content, the STIC Showcase also included 

three live panel sessions aligned to the overarching themes of the 

summit: Engaging People, Deploying Products, and Improving 

Processes. Twenty panelists provided 6-minute pitches to pique 

further interest in their innovations. For Fullerton, participating 

on the Engaging People panel yielded that exact objective. “I have 

followed up with Illinois DOT, a fellow panelist, to be included in 

a series of interviews to collect best practices on internal innova

tion practices,” she says. “Without the Showcase, I wouldn’t have 

known about the work they are doing and it’s been very helpful!”

-

Many STIC Showcase topics clearly supported the idea that 

communication is key to advancing innovation. Washington State 

DOT’s “Webinar Wednesday” series, which shares information 

on their research projects to encourage other agencies to imple

ment their findings, has engaged more than 3,100 participants. 

California DOT’s virtual Innovation Expo 2020, which engaged 

1,350 individuals from 13 States, conveyed the philosophy that 

innovation in transportation requires an ongoing commitment of 

all involved to pursue new ways of conducting business.

-

The transportation community can continue to access all of 

the Showcase content through December 2021 by registering for 

the EDC-6 Virtual Summit at www.labroots.com/ms/virtual-event 

/fhwa-everyday-counts-6-virtual-summit, and clicking on the National 

STIC Network Showcase button. All are encouraged to explore 

and learn more about an amazing variety of homegrown efforts. 

With 245 innovations to choose from, there is bound to be something there to inspire you...and don’t forget to tell your neighbors!

JEFFREY ZAHAREWICZ is the Acting Director for the Center for 

Accelerating Innovation.

The virtual lobby of the National STIC Network Showcase enabled attendees to 

access a range of content from online posters to panel presentations. 

Source: FHWA.
CARMASM

: IMPROVING TRAFFIC FLOWS 

AND SAFETY AT ACTIVE WORK ZONES

FHWA’s CARMASM Program is testing how cooperative driving automation 

can manage work zone congestion and enhance safety.

FHWA’s fleet of vehicles equipped with the 

CARMA Platform are helping researchers test how 

cooperative driving automation can relieve work 

zone congestion and improve safety.

Source: FHWA.

4 | PUBLIC ROADS | SPRING 2021

by PAVLE BUJANOVIĆ, TODD PETERSON, and DENISE BAKAR

Developed by the Federal Highway Administration, the CARMASM Program is leading research on the information 

exchanges and cooperative maneuvers that 

constitute cooperative driving automation 

(CDA). Defined by the Society of Automo

tive Engineers J3216 Standard, CDA aims 

to improve the safety, flow, and efficiency 

of roadway infrastructure by supporting 

the cooperative movement of automated 

vehicles through the use of wireless mobility 

applications. Through software develop

ment activities, the program is building 

numerous CDA features (or applications) 

that will be tested in a set of research tracks 

focused on transportation systems manage

ment and operations. The research tracks 

aim to demonstrate the potential of CDA 

to facilitate system efficiency and safety 

improvements in various areas of the trans

portation ecosystem.

-

-

-

-

The work zone management (WZM) 

use case is part of the CARMA Reliability 

research track. This research track examines 

solutions to nonrecurring congestion on 

freeways and arterials, such as traffic inci

dents and inclement weather, in addition to 

work zone activity. The WZM use case will 

demonstrate the role of CDA in improving 

safety and alleviating work zone-related 

congestion. The program is addressing mul

tiple WZM scenarios, with each scenario 

demonstrating improved network perfor

mance through the application of a specific 

CDA feature.

-

-

-

“The application of CDA to work zone 

management has been among the most chal

lenging cases for automated vehicle opera

tions. The CARMA WZM use case lays a 

foundation for addressing this challenge, 

which is critical to expanding the applica

bility of CDA to other environments,” says 

Dr. Xiaopeng Li, an associate professor at 

the University of South Florida and director 

of the National Institute for Congestion 

Reduction, whose team is developing 

CDA algorithms that will be tested in the 

CARMA ecosystem.

-

-

-

The Work Zone Scenario

The first scenario developed under the 

WZM use case involves a one-lane, two-way 

traffic taper resulting from an active work 

zone on a two-lane arterial street. This sce

nario calls for an active work zone to occupy 

a segment of one lane, requiring vehicles 

equipped with a cooperative automated 

driving system (C-ADS) to temporarily 

merge into the lane traveling in the opposite 

direction to pass the work zone lane closure. 

To accomplish this, the vehicles must 

communicate with CARMA CloudSM and 

CARMA Streets to ensure that it is safe for 

them to enter the work zone. Vehicles are 

equipped with C-ADS technology through 

the installation of CARMA PlatformSM, 

which bestows the Society of Automotive 

Engineers ADS Level 3+ functionality.

-

The work zone scenario proceeds as 

follows: The vehicles equipped with C-ADS 

are traveling on a two-lane arterial that 

contains a work zone. At one section in the 

arterial, one of the lanes is closed. Stationed 

at either end of the work zone are two 

temporary traffic signals; the traffic signals 

are synchronized and have fixed timing to 

allow only one direction of traffic to proceed 

through the work zone at a time. A future 

application will explore use of adaptive 

traffic signal timing based on the presence 

of vehicles in each direction.

The vehicles regularly transmit loca

tion information, via their onboard 

units, to CARMA Cloud through V2X 

-
WWW.FHWA.DOT.GOV | 5

[vehicle-to-everything] Hub. V2X Hub is a 

separate, multimodal open-source software 

system, stored in roadside infrastructure 

such as traffic cabinets, which enables networked, wireless communications between 

participating entities. As the vehicles 

approach the traffic signals near the work 

zone, CARMA Cloud prepares a message 

containing information about the work 

zone lane closure in the intended direction 

of the vehicles. The message identifies the 

virtual perimeter (geofence) for the work 

zone and contains recommended movement 

information for vehicles traveling through 

the geofence—this includes a low speed 

advisory and alternative lane geometry. 

CARMA Cloud transmits the message to 

V2X Hub for broadcast to the approaching 

vehicles. The vehicles receive the message via 

their individual onboard units.

Researchers tested CARMA Platform-equipped 

vehicles in a simulated work zone.

Source: FHWA.

Traffic signals deployed on either end of 

the work zone control traffic movement in 

the work zone. For example, the vehicles in 

the lane with the closure receive the traffic 

green light to proceed, while the vehicles 

in the opposite lane remain stopped at 

a red light. The moving vehicles use the 
6 | PUBLIC ROADS | SPRING 2021

recommended movement information from 

CARMA Cloud to cross the yellow line 

separating the travel lanes, merge to the 

opposite lane, travel at the advised speed 

through the work zone, and merge back 

into their original lane after clearing the 

geofenced area.

Once the traffic signal in the closed lane 

changes to red, there will be a brief “all red” 

period during which both directions face 

a red signal. This ensures that there are no 

vehicles still passing through the work zone 

when the opposite direction receives a green 

signal. After this brief period, the vehicles in 

the open lane receive a green signal to pro

ceed through the work zone. The moving 

vehicles reduce their speed to meet the low 

speed advisory and drive through the work 

zone area. After passing through the work 

zone and exiting the geofenced area, vehicles 

in both directions continue to travel in their 

respective lanes at the posted speed limit.

-

This traffic control pattern continues for 

the duration of the lane closure due to the 

active work zone.

To direct the safe passage of vehicles 

through active work zones, the scenario 

employs the Work Zone Data Exchange 

message specification, which leverages cloud 

services to facilitate information exchanges 

between vehicles, infrastructure, and road 

users. To ensure that the features operate 

safely and in the way they were designed 

for this specific operational design domain, 

the CARMA team conducted functional 

tests prior to validation testing of the CDA 

features required for the scenario.

The first work zone management use case involves a one-lane, two-way traffic taper. Vehicles traveling on 

the side of the road blocked by the work zone must merge into the lane traveling in the opposite direction.

*SPAT is defined as Signal Phase and Timing.

Source: FHWA.

Collaboration

The CARMA Program leverages collabo

ration with stakeholders in government, 

academia, consulting, and the technical 

industry to accelerate advancements in 

CDA research, development, and testing. 

The program’s CARMA Collaborative 

effort teamwork through multiple touchpoints, from webinars and group meet

ings to conferences and panels. CARMA 

products, which are open for collaboration 

on the GitHub development platform 

(

-

-

https://github.com/usdot-fhwa-stol), are 

included in the Open Source Software 

Suite for Intelligent Transportation Systems 

(OSS4ITS), available at https://usdot-oss4its 

.atlassian.net/wiki/spaces/OSSFITS/overview. 

Deployers can use, reuse, and augment the 

tools to help accelerate their programs.

Looking Ahead

The introduction of CDA is expected to 

produce numerous positive impacts to 

the movement of people and goods on 

the Nation’s roads. The WZM use case 

establishes the framework of using CDA 

features in active work zone areas to ease 

congestion and enhance traveler and 

worker safety.

“Better communication between 

vehicles and work zone safety devices 

through CARMA will improve safety 

and vehicle performance though roadway work zone installations, making it 

safer for workers as well as motorists,” says 

David Rush, manager of the Work Zone 

Safety Program at the Virginia Department 

of Transportation.

An engineer performs CDA research using a 

CARMA Platform-equipped vehicle at the FHWA 

Saxton Transportation Operations Laboratory.

Source: FHWA.

The WZM use case highlights the 

enhanced response actions—made possible 

through CDA—to traffic disruptions caused 
WWW.FHWA.DOT.GOV | 7

Work 

Zone

Work 

Zone Geo-fence

Received SPAT (green light)

Speed Advisory and 

Lane Closure

2

by work zones. These enhanced response 

actions, which include improved awareness 

and coordinated movements of vehicles in a 

work zone, will ultimately lead to improve

ments in traffic performance by reducing 

congestion and incident occurrence in 

work zones.

-

“Ultimately, the success of testing will 

bring the Nation one step closer to deploy

ing CDA-based transportation systems 

management and operations strategies for 

managing work zone traffic,” says Barb 

Wendling, chair of the newly formed Soci

ety of Automotive Engineers Cooperative 

Driving Automation System Committee.

-

-

PAVLE BUJANOVIĆ is a CARMA technical manager 

in FHWA’s Office of Operations Research and 

Development, managing various CDA research 

projects and leading the new CARMA Reliability 

research track that includes work zones. He 

earned a B.S. in civil engineering from Syracuse 

University, an M.S. in sustainable design and 

construction from Stanford University, and a Ph.D. 

in transportation engineering from the University of 

Texas at Austin.

TODD PETERSON is a transportation specialist for 

the Office of Operations’ Work Zone Management 

Program. Todd leads FHWA’s Work Zone Data 

Initiative, which has produced a data specification 

and national deployment framework for real-time 

information pertaining to work zone activity, and is 

currently leading a project to expand that effort to 

other nonrecurring events. He earned a B.S. and an 

M.S. in civil engineering from Virginia Tech.

DENISE BAKAR is a contracted communications 

specialist in FHWA’s Saxton Transportation 

Operations Laboratory, leading content strategy 

and outreach activities. She earned an M.A. 

in strategic communications from American 

University and a B.A. from the University of Virginia.

For more background on CARMA, see 

“CARMASM: Driving Innovation” in the 

Winter 2020 issue of Public Roads.
8 | PUBLIC ROADS | SPRING 2021

MICROMOBILITY:

A TRAVEL MODE 

INNOVATION

With increased growth in bikeshare and shared e-scooter systems, FHWA and USDOT 

are helping State DOTs and cities manage micromobility deployment, and are monitoring 

trends and evaluating facilities and design needs.

Micromobility options like e-scooters and bikesharing remain a growing trend in the United States.

© Laura Sandt, Pedestrian and Bicycle Information Center (PBIC).

by JEFF PRICE, DANIELLE BLACKSHEAR, WESLEY BLOUNT, JR., and LAURA SANDT

Micromobility has rapidly proliferated in cities nationwide, proving to be a 

popular transportation option for many 

users. In response to the increasing demand 

for walking and bicycling facilities in 

cities and towns across the country, many 

jurisdictions are exploring micromobility 

as an alternative mode for short trips and 

active transportation.

Because micromobility is still a rela

tively new and emerging mobility option, 

there are various definitions in use of what 

constitutes “micromobility.” Building upon 

the Society of Automotive Engineers International’s Taxonomy and Classification of 

Powered Micromobility Vehicles, the Federal 

Highway Administration broadly defines 

micromobility as any small, low-speed, 

human- or electric-powered transportation 

device, including bicycles, scooters, 

electric-assist bicycles, electric scooters 

(e-scooters), and other small, lightweight, 

wheeled conveyances. Other definitions of 

micromobility focus primarily on powered 

micromobility devices and characterize 

these devices as partially or fully motorized, 

low-speed (typically less than 30 miles [48 

kilometers] per hour), and small size (typi

cally less than 500 pounds [230 kilograms] 

and less than 3 feet [1 meter] wide).

-

-

As of August 2020, there are more than 

260 shared micromobility systems, includ

ing docked and dockless bikeshare and 

e-scooter systems, in the United States, and 

the largest of these shared systems include 

several thousand micromobility devices. 

According to a recent National Association 

of City Transportation Officials (NACTO) 

report, users took 136 million trips in 

2019 on shared micromobility systems, 

a 60 percent increase from 2018. The report 

is available at 

-

https://nacto.org/shared 

-micromobility-2019.

Although micromobility devices may 

be individually owned, the recent surge 

of devices in cities is due primarily to the 

deployment of shared fleets by private com

panies. Shared micromobility systems are 

deployed in targeted service areas with the 

usage generally intended for short trips such 

as “first- and last-mile” connections to com

plete trips made via other modes, including 

transit. Shared fleets provide users with 

on-demand access to devices. These fleets 

are most commonly parked in the public 

right-of-way, either grouped at a dock or as 

dockless devices. Users typically unlock the 

-

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WWW.FHWA.DOT.GOV | 9

devices using a smartphone application or 

key fob.

FHWA Initiatives

In late 2018, the FHWA Office of Plan

ning, Environment, and Realty (HEP) 

began efforts to gather information and set 

the stage for future FHWA micromobility 

research and exploration. With support 

from the U.S. Department of Transporta

tion Volpe Center (Volpe), HEP interviewed 

25 staff across 11 FHWA offices to estab

lish FHWA’s definition of micromobility; 

consider Federal, State, and local roles in 

this emerging area; and develop questions 

for future research. As internal expertise 

grew, HEP expanded coordination efforts to 

establish an internal USDOT micromobility 

working group that comprised staff from 

FHWA, Volpe, the Office of the Secretary, 

the Federal Transit Administration, the 

National Highway Traffic Safety Adminis

tration, and the Intelligent Transportation 

Systems Joint Program Office. The working 

group meets quarterly to track micromobil

ity research and activities across the Depart

ment and provides a forum for exchange 

and discussion to maintain a coordinated 

approach. FHWA also coordinates micromobility topics through internal Mobility 

Innovation and Mobility on Demand work

ing groups, which facilitate the coordination 

of current and future mobility research.

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Through a cooperative agreement with 

the Pedestrian and Bicycle Information 

Center (PBIC), FHWA has supported 

extensive outreach and coordination with 

a variety of external partners. For example, 

PBIC staff were among the first to present 

on micromobility at the Transportation 

Research Board (TRB) Annual Meeting in 

January 2019, sharing research and data 

needs. PBIC and its subcontractor, the 

Institute of Transportation Engineers (ITE), 

partnered to host a half-day workshop at 

ITE’s Annual Meeting in July 2019, engag

ing more than 45 participants from around 

the country in a micromobility tour around 

Austin, TX, and a meet-and-greet with 

several micromobility operators to try out 

their devices. In late 2019, FHWA coordi

nated with PBIC to produce two informa

tion briefs—The Basics of Micromobility and 

Related Motorized Devices for Personal Transport and E-Scooter Management in Midsized 

Cities in the United States—and develop a 

curated set of resources on its website at 

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-

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www.pedbikeinfo.org/topics/micromobility.cfm.

To better understand the impact of 

micromobility on the transportation network, FHWA is coordinating with public 

and private sector stakeholders to explore 

ways to aid the research and deployment of 

innovative multimodal travel options that 

will be safer and more efficient for all multimodal device users. FHWA regularly partic

ipates in coordination meetings and virtual 

conferences held by the American Public 

Transportation Association’s Integrated 

Mobility and Communities Consortium, 

TRB’s Mobility Management Committee 

and Research and Technology Coordinating 

Committee, and the North American Bikeshare Association.

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Additionally, FHWA supports the 

micromobility efforts of other Federal 

agencies, such as supporting the National 

Science Foundation’s Smart and Connected 

Communities Program and participating in 

reviews of transportation-related projects, 

participating in the National Park Ser

vice’s Emerging Mobility Working Group 

to exchange information on the state of 

the practice and ongoing micromobility 

activities, and presenting during the 

Consumer Product Safety Commission’s 

Micromobility Forum Webinar, an event to 

discuss micromobility safety considerations 

in research, data, standards, and policy. In 

early 2020, HEP also interviewed 27 staff 

from 9 Federal agencies—including the 

U.S. Department of Energy and Centers for 

Disease Control and Prevention in addition 

to those previously mentioned—to share 

micromobility research activities and help 

identify potential gaps in research.

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Based on feedback received during 

various outreach activities, FHWA devel

oped a micromobility fact sheet (available 

at 

-

www.fhwa.dot.gov/livability/fact_sheets 

/mm_fact_sheet.cfm) and two USDOT and 

FHWA micromobility handouts (available 

at www.fhwa.dot.gov/livability/resources/#micro) 

to communicate FHWA’s ongoing 

micromobility research and coordina

tion activities.

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Examples of powered micromobility devices and their classifications according to PBIC.

© Laura Sandt, PBIC.

Community Experiences

Micromobility devices and shared systems 

offer new and powerful ways to help people 

meet their transportation needs. E-bikes and 

e-scooters can help many people overcome 

barriers that would otherwise prevent them 

from taking active forms of transportation. 

At the same time, there is a need to be 

mindful of who benefits from these systems, 

who may be harmed or excluded, and how 

micromobility systems can be designed to 

meet their full potential in supporting safe, 

equitable, and resilient communities.

A 2019 report produced for the New 

Jersey Department of Transportation 

and FHWA, E-Scooter Programs: Current 

State of Practice in U.S. Cities, notes that 

“E-scooters are an important transportation 

alternative for first mile/last mile trips, for 
10 | PUBLIC ROADS | SPRING 2021

neighborhoods underserved by conventional 

transit systems, and for individuals who do 

not own or have access to cars. Dockless 

e-scooter share programs, with the sensible 

equity policies, lend themselves to serving 

disadvantaged communities.” The report is 

available at http://njbikeped.org/wp-content/

uploads/BPRC-E-Scooter-Study-2-2020.pdf.

Cities are experimenting with a range of 

approaches to actively manage micromobil

ity programs to ensure positive safety and 

equity outcomes. Cities are examining the 

effects of various safety practices—including 

how to set service areas, determine max

imum safe micromobility device speeds, 

and restrict vehicle speeds or times of 

operation in areas with dense micromobility 

ridership—and exploring approaches to 

incentivize helmet use.

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Cities also are investigating micromo

bility parking needs in relation to concerns 

about sidewalk accessibility for pedestrians 

with disabilities. For a deeper dive into 

parking management practices in Austin, see 

the July 2020 issue of FHWA’s “Fostering 

Multimodal Connectivity Newsletter.”

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Communities are regularly engaging 

the public, and many are seeking to build 

a culture of safety through micromobility 

ambassador programs, rider training, and 

programs designed to support safe tourism and micromobility use during special 

events and festivals. By building program 

evaluation plans, conducting pilot studies, 

establishing data requirements and data use 

agreements, and partnering with diverse 

agencies, communities are beginning to 

develop protocols and training for injury 

reporting and incident management and 

learning about how to improve the safety of 

all road users. In many places, agencies are 

creating cross-departmental coordination 

teams, developing new funding streams, 

and supporting the implementation of new 

roadway infrastructure, operations, and 

parking spaces to support micromobility.

Noteworthy local highlights include:

• Phoenix, AZ: Through a pilot 

program, Phoenix is allowing 

e-scooters in its downtown area and is 

aiming to control usage, distribution, 

and parking through geofencing and 

clear signage and maps during the 

pilot phase. The city is conducting 

an extensive safety and ridership 

data evaluation.

• Denver, CO: Denver is evaluating 

e-scooters’ ability to help achieve 

reductions in single-occupancy 

vehicle mode share goals. The city 

and county of Denver’s micromobility 

pilot flows through their Transit 

Amenity Program, which encourages 

connections to public transportation.

• Portland, OR: Portland has been 

considered a leader in conducting 

robust evaluations of its e-scooter 

pilot program and putting into place 

programs to support the Portland 

Bureau of Transportation’s equity and 

accessibility goals.

A parking hub for bicycles with dockless, shared scooters parked beside it in Austin, TX.

© Laura Sandt, PBIC.

The city of Santa Monica, CA, is one 

of the longest-running examples in the 

United States of successfully incorporating 

micromobility into the community’s shared 

mobility program. Santa Monica is a coastal 

city west of downtown Los Angeles with 

a population of roughly 91,000 people. 

The city is a leader in sustainable mobility, 

and was the first in Los Angeles County to 

launch a municipally owned and operated 

bicycle share system in 2015.

Shared micromobility devices such 

as bicycles, electric bicycles (e-bicycles), 

and e-scooters may create a more diverse, 

convenient, and accessible transporta

tion network, which can provide more 

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WWW.FHWA.DOT.GOV | 11

transportation options, reduce congestion, 

and improve quality of life. 

Santa Monica strengthened administra

tive language regarding equitable access to 

these devices. For example, device operators 

must establish and promote low-income 

qualified rates for shared mobility device use 

and offer incentives (such as education, outreach, and payment plans) for low-income 

or other disadvantaged users. For more 

information, see 

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www.fhwa.dot.gov/livability 

/case_studies/santa_monica.

In August 2020, the city of Chicago, IL, 

launched its second scooter pilot program 

with a particular focus on communities 

without equitable access to transportation. 

“This new scooter pilot program builds 

on our experience in the first pilot, focuses 

on safety for scooter riders and the general 

public, and requires a more equitable distri

bution of scooters,” said Chicago Depart

ment of Transportation Commissioner 

Gia Biagi in a press release announcing the 

program. “Particularly during [this] public 

health crisis, it’s important that we explore 

innovative options that make it easier for 

Chicagoans to get around.”

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The E-Scooter Programs: Current State 

of Practice in U.S. Cities report highlights 

practices from 11 different micromobility 

programs and examines the way in which 

equity, safety, and other considerations were 

integrated into various aspects of the programs. For additional indepth case studies, 

pilot program evaluations, and resources, 

visit PBIC’s Micromobility topics page at 

www.pedbikeinfo.org/topics/micromobility.cfm.

Considerations for Wider 

Use and Adoption

While the majority of e-scooter trips end 

without incident, much work remains to 

be done to improve comfort and safety 

for e-scooter riders with different levels of 

experience, training, and travel needs. A 

tracker of e-scooter fatalities, maintained by 

the University of North Carolina’s Highway Safety Research Center, shows that 20 

of the 24 e-scooter fatalities in the United 

States involved motor vehicles, including 

some heavier vehicles and trucks.

In light of the potential for safety 

concerns, the Governor’s Highway Safety 

Association produced a report that exten

sively discusses the needs around speed 

management, education, improved roadway 

design, and other community engagement 

essentials to help mitigate risks for vulner

able road users. Shared Micromobility in 

the U.S.: 2019—a report by the National 

Association of City Transportation 

Officials—and other research studies on 

shared micromobility echo these findings, 

calling for more attention to the need for a 

connected network of facilities dedicated to 

serving micromobility.

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Looking Ahead: Research 

and Collaboration

Regulation and management of micromobility occurs primarily at State and 

local government levels. Current Federal 

law (23 U.S.C. 217(h)) prohibits motor

ized vehicles from nonmotorized trails 

and pedestrian walkways that use Federal 

highway funds (with limited exceptions 

for maintenance, snowmobiles, motorized 

wheelchairs, and electric bicycles as defined 

in 23 U.S.C. 217(j)(2)) and from nonmo

torized trails that use Recreational Trails 

Program funds under 23 U.S.C. 206 (except 

for motorized wheelchairs). There are no 

Federal prohibitions for micromobility 

vehicles using roadways or trails open for 

motorized use.

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Some cities are exploring how to incentivize helmet use to improve 

the safety of micromobility transportation.

© Andrey_Popov / Shutterstock.com.
12 | PUBLIC ROADS | SPRING 2021

State legislatures and transportation 

departments are actively working to define 

lightweight vehicles and operating con

ditions for e-scooters, e-bikes, and other 

emerging dockless mobility technologies. 

USDOT is helping State transportation 

agencies and cities manage micromobility 

deployment through various activities such 

as coordinating and conducting research, 

developing resources and case studies, incen

tivizing innovative and accessible mobility 

through pilots and deployments, and gath

ering information and data on micromobil

ity safety issues to help reduce fatalities and 

serious injuries. 

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FHWA is exploring research 

opportunities to support micromobility. 

The near-term goal is to focus on five 

high-priority micromobility research areas: 

safety, equity, resiliency, user behavior, and 

curbside management. These topics were 

identified through existing research scans, 

interviews with relevant FHWA staff and 

subject matter experts, and input from 

members of the USDOT Micromobility 

Working Group convened by the Office of 

Human Environment. That office intends 

to continue coordination and collaboration 

with other FHWA offices and USDOT 

operating administrations in developing 

these research topics into formal research 

needs statements, identifying funding, and 

coordinating research implementation.

“FHWA and USDOT are well posi

tioned now to expand coordination and 

collaboration efforts with universities, the 

private sector, and other domestic and international stakeholders to monitor trends and 

evaluate facilities and design needs,” says 

Gloria M. Shepherd, the Associate Admin

istrator for Planning, Environment, and 

Realty at FHWA.

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This national capacity building effort 

will aid in future review of legislation and 

policy development to accommodate micromobility in the Nation’s evolving multimodal transportation system.

Bicyclists and e-scooter riders use a separated bike lane in Austin, TX.

© Laura Sandt, PBIC.

JEFF PRICE is a transportation specialist with 

the FHWA Office of Human Environment. He is a 

transportation engineer and community planner 

with more than 20 years of experience in the 

transportation industry advising on multimodal 

transportation and planning issues. He holds an 

M.S. in urban and environmental planning from the 

University of Virginia and a B.S. in civil engineering 

from the University of New Brunswick.

DANIELLE BLACKSHEAR is a transportation special

ist with the FHWA Office of Human Environment. 

She provides technical assistance to trans

portation practitioners to advance multimodal 

transportation systems planning and specializes 

in equitable and accessible mobility innovation. 

She received her bachelor and master’s degrees 

in urban and environmental planning from the 

University of Virginia.

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WESLEY BLOUNT, JR., is a transportation special

ist with the FHWA Office of Human Environment. 

He serves as the program manager for the Safe 

Routes to School Program and oversees the agree

ments with PBIC and the Volpe Center to foster col

laboration around micromobility, connectivity, and 

safety. He holds a bachelor’s degree in marketing 

and masters in transportation management from 

Morgan State University.

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LAURA SANDT is a senior research associate at the 

University of North Carolina at Chapel Hill Highway 

Safety Research Center and the director of PBIC. 

She holds a master’s degree in city and regional 

planning and a PhD in epidemiology, both from the 

University of North Carolina at Chapel Hill.

For more information, visit www.fhwa.dot 

.gov/livability or contact Wesley Blount, Jr., 

(202–366–0799, Wesley.Blount@dot.gov), 

Danielle Blackshear (202–366–2064, 

Danielle.Blackshear@dot.gov), or Jeff Price 

(202–366–0280, Jeff.Price@dot.gov).
WWW.FHWA.DOT.GOV | 13

FOCUSING ON 

PEDESTRIAN SAFETY

FHWA and other agencies across USDOT are continually addressing safety 

concerns for pedestrians by developing and researching effective tools and 

countermeasures and by coordinating projects, plans, and discussions with 

State and local officials and safety advocates.

This midblock crosswalk includes many STEP features including a high-visibility crosswalk, a pedestrian refuge island, lighting, and signage.

Source: FHWA.

by TAMARA REDMON, ANN DO, REBECCA T. CROWE, DARREN BUCK, and MICHAEL S. GRIFFITH

I

n 2019, pedestrian fatalities decreased 

by almost 3 percent from 2018 figures, 

according to estimates from the National 

Highway Traffic Safety Administration. This 

is good news, particularly because pedestrian 

fatalities had risen in recent years, both in 

number and in percentage of all highway 

mortalities. In 2018, 6,283 pedestrians died 

from roadway crashes, the highest toll since 

1990, and from 2009 to 2018, pedestrian 

fatalities in crashes increased 53 percent, 

and the pedestrian share of all highway fatal

ities increased 42 percent.

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NHTSA will be working tirelessly to 

continue the recent downward trend, and 

pedestrian safety also remains a big concern 

of the Federal Highway Administration. 

FHWA’s Office of Safety; Office of Safety 

Research and Development (R&D); Office 

of Planning, Environment, and Realty; and 

Resource Center Safety and Design Team 

are undertaking a series of activities that will 

help increase pedestrian safety.

Collaborative Efforts: Office 

of Safety, Office of Safety 

R&D, and Resource Center

Pedestrian safety is a priority of FHWA and 

has been a focus area since 2004. One of the 

ways the agency is leveraging resources is by 

concentrating on the States and cities with 

the highest pedestrian and bicyclist fatali

ties. The 17 States and 34 cities that have 

the most pedestrian and bicyclist fatalities 

receive technical assistance with safe facility 

design, data analysis and action plan devel

opment, training, and support for a wide 

range of analysis tools and countermeasures. 

FHWA reviews and revises the focus areas 

and data every 5 years or so.

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Source: FHWA.
14 | PUBLIC ROADS | SPRING 2021

A midblock crossing with rectangular rapid flashing beacons. 

Source: FHWA.

Technical Assistance

FHWA has developed a number of train

ings, with well over 300 courses delivered 

and more than 6,000 people trained. In 

addition, FHWA offers popular quar

terly webinars that consistently host 500 

attendees. On top of providing training on 

the design of safe facilities, assisting with 

crash analysis, and extending specialized 

technical assistance, FHWA has helped 

many of the States and cities develop 

pedestrian safety action plans. Among other 

accomplishments, FHWA developed the 

New York State Pedestrian Safety Action Plan, 

which won the 2018 Governor’s Highway 

Safety Award and helped lead the State to a 

large drop in fatalities.

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STEP Up to Safety

The FHWA Safe Transportation for Every 

Pedestrian (STEP) program, an innovation 

of Every Day Counts, began in 2017 with 

a goal of helping State and local agencies 

reduce pedestrian fatalities at roadway 

crossings. The STEP program promotes 

the “spectacular seven” countermeasures 

to improve pedestrian safety at crossings: 

crosswalk visibility enhancements; raised 

crosswalks; pedestrian refuge islands; 

rectangular rapid flashing beacons; pedes

trian hybrid beacons (PHBs); road diets; 

and leading pedestrian intervals. STEP has 

documented more than 30 case studies 

that highlight the safety benefits of each of 

the countermeasures.

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PHBs constitute one of the most 

effective countermeasures for multilane 

and higher speed roads, as highlighted by 

case studies in Florida and North Carolina. 

The Florida Department of Transportation 

(FDOT) installed multiple PHBs along a 

corridor in Tampa.

“The initial crash reduction we’ve seen 

on East Hillsborough Avenue has been very 

encouraging,” says Alex Henry of FDOT 

District 7. “I think it is proof positive that 

a combination of relatively inexpensive and 

easy-to-implement countermeasures can 

help to make an impact on even our most 

challenging corridors.”

A pedestrian uses a pedestrian hybrid 

beacon at a midblock trail crossing. 

Source: FHWA.

FHWA recently released STEP Studio, 

a toolbox for selecting and implementing 

countermeasures for improving pedestrian 
WWW.FHWA.DOT.GOV | 15

crossing safety. STEP Studio is a visual and 

interactive resource that follows the steps 

outlined in FHWA’s Guide for Improving 

Pedestrian Safety at Uncontrolled Crossing 

Locations (FHWA-SA-17-072) to identify 

potential countermeasures for a variety 

of contexts.

FHWA is challenging agencies to 

“STEP UP” to implement proven safety 

countermeasures at pedestrian crossings. 

FHWA kicked off the STEP UP campaign 

in summer 2020—focusing on pedestrian 

crossing safety in dark conditions, between 

intersections, and involving older pedestri

ans. The STEP program recently learned 

that the city of Roanoke, VA, installed lead

ing pedestrian intervals across its downtown 

area in summer 2020.

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The STEP program provides technical 

assistance to agencies across the United 

States and has produced a variety of edu

cational resources, such as tech sheets and 

videos, to promote the “spectacular seven” 

countermeasures. The STEP team has 

worked with dozens of States to develop 

near-term action plans and conduct road 

safety audits. The STEP team continues to 

work on additional videos to explain the 

relationship between speed, visibility, and 

pedestrian safety, and the team developed 

a set of lesson plans for youth between 

kindergarten and eighth grade that will 

help students learn about pedestrian safety 

through STEM (science, technology, engi

neering, and mathematics).

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For the latest on the STEP program, visit 

https://safety.fhwa.dot.gov/ped_bike/step.

Pedestrian crossing sign with embedded LEDs.

© Texas A&M Transportation Institute.

Global Benchmarking

FHWA is undertaking a global benchmark

ing study on reducing pedestrian fatalities 

though planning and application of safety 

strategies on principal (nonfreeway) and 

minor arterials. The goal of the study is 

to identify successful practices, policies, 

and innovations that could be applied in 

the United States to make existing and 

planned urban signalized arterials safer 

for pedestrians, as most U.S. pedestrian 

fatalities occur on arterials, especially under 

dark conditions.

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The primary function of an urban arte

rial is to deliver traffic from collector roads 

to freeways or expressways, and between 

urban areas at the highest level of service 

possible. These roads generally have faster 

moving traffic and more vehicle lanes. They 

prioritize vehicle movement over pedestrian 

mobility and often lack convenient cross

ing opportunities.

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FHWA’s global benchmarking study is 

very timely to address the pedestrian safety 

crisis by (1) learning from the success of 

other countries that have been successful 

in reducing pedestrian fatalities on urban 

arterials; (2) identifying practices and 

policies that could be applied in the United 

States to achieve similar results; and (3) 

systemically implementing the findings 

throughout the transportation cycle within 

State and local highway agencies and metro

politan planning organizations.

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Strategic Planning

Finally, the FHWA Office of Safety recently 

completed a project to develop a Pedestrian 

and Bicyclist Safety Strategic Plan. The plan 

is an update to the 2010 Pedestrian Safety 

Strategic Plan (FHWA-SA-10-035) to pro

vide FHWA’s Pedestrian and Bicycle Safety 

program direction for the next 5 to 10 years. 

The plan augments the initial program 

and plan to include the bicycle mode and 

integrate the latest state of practice on mul

timodal safety into a “big picture” guiding 

vision with the ultimate objective of reduc

ing pedestrian and bicyclist fatalities in the 

United States, while also increasing accessi

bility. The updated strategic plan is (1) data 

driven, taking advantage of existing national 

resources and databases on multimodal 

safety trends; (2) anchored in the state of the 

practice of vast national knowledge on mul

timodal safety, design, and policy research; 

and (3) focused on directly implementable 

countermeasures and strategies.

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Office of Safety R&D

The Office of Safety R&D’s primary activ

ities reduce injuries and fatalities by better 

understanding the contributing factors and 

causes of pedestrian and bicyclist serious 

injuries and fatalities, identifying and 

evaluating potential safety improvement 

measures, fostering public awareness of 

pedestrian and bicycle safety matters, and 

providing resources for use at the national, 

State, and local levels. The Office of Safety 

R&D is currently undertaking several 

pedestrian and bicyclist safety-focused 

research projects.

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The Safety Study on Pedestrian Cross

ing Warning MUTCD W11-2 Sign with 

Embedded Light Emitting Diodes (LEDs) 

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16 | PUBLIC ROADS | SPRING 2021

looks at a device being used that has LEDs 

embedded into the border of a crossing sign. 

The purpose of the study is to investigate 

the performance of pedestrian or school 

crossing warning signs that have embed

ded LEDs that are activated by the pedes

trian (not flashing 24/7). The project will 

determine the effectiveness of the embedded 

LEDs in terms of whether drivers are appro

priately yielding to pedestrians crossing 

the street.

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For the FHWA research project Develop

ment of Pedestrian Intersection Crash Mod

ification Factor (CMF), the research team 

has been tasked with analyzing the relationships between right-turn operations and 

pedestrian-vehicle crashes at signalized intersections. The team aims to develop a CMF 

for signalized intersection corner radius and 

to investigate how turning speeds vary as a 

function of the design at the intersection 

corner. The crash analysis is currently ongo

ing. The final selected model from the speed 

study can be used to predict the average and 

85th percentile turning speeds for a given 

corner radius. The anticipated CMF can 

be used to consider the effects of signalized 

intersection corner radius on crashes.

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FHWA recently started a project entitled 

Evaluation of Aesthetically Treated Crosswalks, which will use a series of closedcourse studies to investigate behavior 

associated with aesthetic treatments of 

crosswalks. Crosswalk pavement markings 

provide guidance for pedestrians crossing 

streets by defining and delineating the 

path. In recent years, some State and local 

jurisdictions have added color, patterns, 

and artwork to crossings within the space 

between crosswalk markings. The objective 

of the study is to determine if and how the 

aesthetically treated crosswalks impact road 

users’ recognition of and behavior at the 

crosswalk. The outcomes of this project can 

help FHWA continue to refine the stan

dards and guidance on the design and use of 

crosswalk markings.

-

 Finally, the study Investigating How 

Multimodal Environments Affect Multitasking Driving Behaviors will examine 

multitasking behaviors when drivers are in 

environments that include large numbers 

of pedestrians and cyclists. Multitasking 

behavior refers to any secondary activity not 

related to the primary driving task, such 

as engagement on mobile devices, eating, 

drinking, and talking to passengers. Natu

ralistic driving data are critical to achieve the 

objectives of this study, as they offer detailed 

and objective information about the type 

and frequency of driver distracting behaviors 

in everyday driving situations. They also 

provide a broader context of contributing 

factors (environment, weather, traffic, 

season) given a driver’s sociodemographic 

characteristics and vehicle information 

(type, speed, etc.).

-

“The Office of Safety R&D is supporting the USDOT’s and FHWA’s first 

strategic objective of safety and reducing 

transportation-related fatalities and serious 

injuries, particularly for pedestrians,” says 

Brian Cronin, director of the Office of 

Safety R&D and the Office of Operations 

R&D. “As one can see from the projects 

included here, our work focuses on studying 

countermeasures, road geometries, [and] 

traffic control devices, as well as evaluating 

behavior. We are adding technology to our 

Smart Intersection [at the Turner-Fairbank 

Highway Research Center], expanding 

our simulator capabilities, and developing 

new virtual reality research tools. Feedback 

received from the USDOT Summit on 

Pedestrian Safety and the update of the 

FHWA Bicycle and Pedestrian Strategic 

Plan will guide the direction of our future 

pedestrian safety research.”

The speed of right-turning vehicles can affect pedestrians crossing at an intersection, including whether they start to cross and how quickly they cross.

© Texas A&M Transportation Institute.

Office of Human Environment

FHWA’s Office of Human Environment, 

part of the Office of Planning, Environ

ment, and Realty, promotes safe, comfortable, and convenient walking and bicycling 

for people of all ages and abilities. The 

office supports pedestrian and bicycle 

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WWW.FHWA.DOT.GOV | 17

transportation through planning, program

matic support, funding, policy guidance, 

program management, and resource devel

opment. In partnership with NHTSA, the 

Office of Human Environment supports 

the Pedestrian and Bicycle Information 

Center, which develops and disseminates 

resources vital to advancing mobility, access, 

equity, and safety. Through its website 

(

-

-

www.pedbikeinfo.org) and monthly newslet

ters, the center provides timely and rele

vant pedestrian and bicycle safety research 

for practitioners.

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FHWA’s Multimodal Network Con

nectivity Pilot grant program supported 

eight communities in their efforts to define 

and analyze where and why people walk 

and bike on their transportation networks. 

Multimodal network analyses like these can 

assist safety practitioners in predicting where 

pedestrian- and bicyclist-involved crashes 

may occur.

-

The East Central Florida Regional 

Planning Council and MetroPlan Orlando 

used this grant to create the Land Overlaid 

on Transportation Information System 

(LOTIS), which combines land-use and 

transportation attribute data into a geodatabase that can be used for a variety of pur

poses, including safe system analysis. Using 

the system, the agencies were able to analyze 

the entire regional transportation network 

and create a safety score rating for every 

road segment that estimates pedestrian and 

bicycle crash risk. The public can browse the 

system’s analysis products at 

-

www.ecfrpc.org 

/lotis, and the Office of Human Environ

ment expects to post a summary report on 

the Multimodal Network Connectivity Pilot 

grant program in early 2021.

-

In response to a stated need from practi

tioners for quick, practice-ready research in 

pedestrian and bicycle transportation, the 

Office of Human Environment established 

the Fostering Innovation in Pedestrian and 

Bicycle Transportation pooled fund study 

in 2017. With participation from 14 State 

department of transportation partners and 

other FHWA offices, this pooled fund has 

conducted research into green pavement 

markings for bicyclists, crosswalk marking 

designs, and curb extensions for pedestrians.

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© PeskyMonkey / iStock.com.

A Coordinated Approach

Although FHWA conducts many activities 

to address pedestrian safety and mobility, 

a coordinated approach across FHWA, 

NHTSA, and the Office of the Secretary of 

Transportation was necessary to successfully 

plan and launch the USDOT Summit on 

Pedestrian Safety held in July 2020. The vir

tual summit discussed issues around pedes

trian safety and the initiatives and actions 

that can improve the safety of pedestrians. 

The webinars included remarks from former 

U.S. Secretary of Transportation Elaine L. 

Chao, former FHWA Administrator Nicole 

R. Nason, NHTSA Deputy Administrator 

James C. Owens, and speakers from trans

portation safety organizations.

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In advance of the webinars, coordinators 

developed a draft list of current and planned 

USDOT actions to enhance pedestrian 

safety and shared it with participants. The 

list identified what the Office of the Secre

tary of Transportation, FHWA, NHTSA, 

and other USDOT modes intended to 

accomplish in the next 2 years. The actions 

focused on:

-

• Developing or updating resources, 

tools, and plans

• Implementing new and revised 

campaigns, programs, and initiatives

• Creating or revising curricula

• Researching better ways to improve 

pedestrian safety

Participants provided feedback solic

ited through interactive polling questions, 

public chat pods, the website, and email. A 

review of these comments revealed several 

important themes: speed, roadway design, 

technology, and funding.

-

Speed: Do a better job of setting speed 

limits, design roadways to encourage 

slower speeds, approve laws and regula

tions including the use of speed cameras, 

and conduct more education on the dan

gers of speeding to change the cultural 

mindset that does not view speeding as a 

serious problem.

-

-

Roadway Design: Support pedestrian 

safety through traffic calming, estab

lish “no car” or slow zones, conduct 

pedestrian safety audits, and implement 

complete streets policies.

-
18 | PUBLIC ROADS | SPRING 2021

Technology: Support technology and 

new vehicle design—including con

nected and autonomous vehicles—that 

enable drivers to see pedestrians sooner 

and engage emergency braking systems 

when necessary.

-

Funding: Address the lack of funding 

that prevents State and local govern

ments from making needed pedestrian 

safety improvements.

-

The collaborative team is gathering and 

responding to input aimed to ensure that 

the USDOT Pedestrian Safety Action Plan

is as comprehensive as possible. FHWA, 

NHTSA, and the other USDOT agency 

partners will monitor plan progress to guar

antee that pedestrian safety remains at the 

forefront of public attention. The USDOT 

Pedestrian Safety Action Plan includes actions 

that will be completed in the near term and 

those that will be completed in December 

2021 and beyond. The plan is available at 

-

https://highways.dot.gov/sites/fhwa 

.dot.gov/files/2020-11/FHWA_PedSafety 

_ActionPlan_Nov2020.pdf.

Setting a Course for the Future

Although pedestrian crashes, fatalities, 

and injuries remain a worrisome issue, 

it is encouraging to see some downward 

movement in the latest numbers. FHWA 

and other USDOT modal agencies remain 

committed to increasing pedestrian safety 

and moving those numbers downward. 

Although FHWA offers many projects, 

activities, and research planned and ongo

ing, the USDOT Pedestrian Safety Action 

Plan and FHWA’s updated Strategic Plan 

will help set a definite course for the future.

-

“Our shared goal is to get to zero 

deaths,” says Cheryl Walker, FHWA’s Asso

ciate Administrator for Safety. “We commit 

to working with all of you to promote safe, 

comfortable, convenient walking for people 

of all ages and all abilities.”

-

TAMARA REDMON is the manager of the Pedestrian 

and Bicycle Safety Program in FHWA’s Office of 

Safety, where she has worked for 24 years. In her 

job, she develops programs and resources to help 

reduce pedestrian and bicyclist crashes, fatalities, 

and injuries. She earned a B.A. from Virginia Tech 

and an M.A. from Marymount University.

ANN DO has been the program manager for the 

FHWA Pedestrian and Bicycle Safety Research 

program in the Office of Safety R&D since 2001. 

She specializes in research related to safety 

effectiveness evaluations, pedestrians, bicyclists, 

human factors engineering, and geometric design. 

She received a B.S. in civil engineering from the 

Virginia Tech Transportation Institute.

REBECCA T. CROWE is a transportation specialist 

with FHWA’s Office of Safety and manages the 

Every Day Counts STEP Program and road diet 

and road safety audit initiatives. She holds a 

B.S. in urban studies and planning from Virginia 

Commonwealth University and an M.A. in 

transportation policy, operations, and logistics 

from George Mason University.

DARREN BUCK is the program coordinator for 

the Pedestrian and Bicycle Program in FHWA’s 

Office of Human Environment and oversees a 

variety of projects to research and promote safe, 

comfortable, and complete networks for bicycle 

and pedestrian travel. He is a graduate of Virginia 

Tech’s Urban and Regional Planning program, and 

has an M.B.A. from the University of Maryland.

MICHAEL S. GRIFFITH is the director of FHWA’s 

Office of Safety Technologies. He provides 

national leadership for safety technologies 

and countermeasures, policy initiatives, and 

effective safety investments. He holds an M.S. in 

transportation engineering from the University 

of Maryland, an M.A. in statistics from the State 

University of New York at Buffalo, and a B.A. in 

business management from Ithaca College.

For more information, visit 

https://safety.fhwa.dot.gov/ped_bike 

or contact tamara.redmon@dot.gov.

The USDOT Pedestrian Safety Action Plan includes actions that will be completed in the 

near term and those that will be completed in December 2021 and beyond.

Source: FHWA.
WWW.FHWA.DOT.GOV | 19

Looking

to the Sky for 

Geotechnical 

Data States are using data from 

unmanned aerial systems to help predict geological 

threats, prioritize mitigation efforts, and aid recovery 

after an event occurs—with reduced 

costs and improved 

safety. 

by DERRICK DASENBROCK, JAMES GRAY, BEN RIVERS, TY ORTIZ, 

JODY KUHNE, and KRYSTLE PELHAM

Unmanned aerial systems (UAS) can provide 

geotechnical data to transportation agencies 

while increasing safety and efficiency. These 

systems can obtain important information, 

such as rock joint condition and orientation, 

in locations with difficult access. 

© University of Vermont 

Spatial Analysis Lab.

Transportation projects use unmanned aerial systems 

(UAS)—often referred to as 

drones—for many purposes, such 

as aerial photography, recon

naissance, surveying, structural 

inspection, and monitoring for 

documentation, safety, and secu

rity. The benefits of using UAS 

include improved access, better 

quality, increased safety, greater 

speed, and improved efficiency.

-

-

Although most geotechni

cal information lies below the 

ground surface, UAS can evaluate 

landslides, rockfall, embankment 

distress, settlement, sinkholes, 

and similar conditions where 

measurements associated with

-
20 | PUBLIC ROADS | SPRING 2021

visible ground features and ground deforma

tion provide useful information about the 

subsurface. UAS can also detect the rate of 

change of these features—which can offer 

insights on causality, such as seasonal or 

weather influences, like rainfall events.

-

UAS are most productive in dangerous 

or hard-to-access sites, or locations where 

an aerial big picture bird’s-eye—or perhaps 

‘drone’s-eye’—view is useful, or critical, to 

a complete understanding of a site. Aerial 

views are often beneficial because of the 

large scale of some distress features associ

ated with landslides and rockfalls. For geotechnical purposes, high-resolution photos, 

three-dimensional (3D) point measurements 

from airborne laser scanning (commonly 

LiDAR, light detecting and ranging), or 

structure-from-motion image processing 

and associated topographic change detection 

are powerful tools to characterize sites, assess 

defining geologic features and geohazard 

threats, and measure movement over time.

-

A rockfall event at the southern portal of the Silver Creek Cliff Tunnel on Minnesota Highway 61 in November 2018 

filled the catchment area between the rock face and the protective barrier. UAS can provide safer inspection 

of sites with recent failures, particularly when site safety is further reduced by snow and ice cover. 

© Minnesota Department of Transportation.

The Impact of Rock-Slope 

Failures and Rockfalls

The American West is known for its rugged 

geography and impressive mountainous 

terrain. Whether driving on I–70 near Idaho 

Springs, CO; traveling on the Seward Highway between Anchorage and the Kenai Pen

insula in Alaska; or approaching the Knapps 

Hill Tunnel on U.S. 97A in Washington 

State, drivers may encounter an extensive 

delay or road closure due to a rockfall 

event. These events are not limited to the 

West. Many examples of soil and rock slope 

failures also come from the eastern United 

States, from the Blue Ridge Mountains in 

North Carolina to the White Mountains 

of New Hampshire, or even mid-continent 

areas along rivers and lakeshores, such as in 

northern Minnesota. While geologists and 

engineers strive to design safe highway corri

dors, rockfall events remain a regular occur

rence from of a variety of causes. Natural 

weathering, freeze-thaw cycles, vegetation, 

earthquakes, rainfall, and other conditions 

can lead to rockslides and rockfall.

-

-

-

Rockfall events often result in significant 

impact to the traveling public. Aside from 

the obvious safety concerns posed by large 

rocks falling near or on vehicles, drivers 

avoiding these rocks or maneuvering to 

reroute can create additional hazards. Roadway closures to prevent crashes and ensure 

motorist safety, which often occur with 

little or no advance warning, can result in 

significant inconvenience from initial travel 

delay and lengthy detour routes. Large-scale 

rock-slope failures can even disrupt routes 

for months and impact local and regional 

economies, as described in a 2010 report, 

Economic Impact of Rockslides in Tennessee 

and North Carolina, prepared for the Appa

lachian Regional Commission. 

-

Rockfalls can be controlled by a variety 

of proactive measures that include rock scal

ing, trim-blasting, mechanical stabilization, 

and rockfall catchment systems. These are 

-
WWW.FHWA.DOT.GOV | 21

often effective strategies to reduce the risk to 

the traveling public. Some sites use multiple 

control techniques. Proactively preventing 

all possible rockfall events is impractical, but 

tools are available to help prioritize mitiga

tion and aid recovery after an event occurs.

-

The success of the pre-event risk assess

ment or post-event mitigation strategies is 

based on an understanding of failure mech

anisms, geometry, and the condition of the 

materials. While the strength of intact rock 

is an important characteristic, the discon

tinuities within the rock mass structure—

such as the fissures, fractures, joints, faults, 

and bedding planes, and their condition— 

usually control how failures occur. These 

features often follow a geometric pattern 

locally and sometimes over large areas such 

as complex joint sets and systems.

-

-

-

Obtaining quality rock slope information 

can be a risky endeavor involving putting 

people on potentially unstable terrain to 

map out geometric features and character

istics of rock formations. Today, transpor

tation agencies are using UAS to conduct 

these surveys more safely and more effi

ciently. The digital information acquired by 

UAS can be quickly processed and deployed 

to help expedite project delivery.

-

-

-

For example, the Colorado Department 

of Transportation (CDOT) created a digital 

model of a rock slope using UAS data and 

quickly designed a trim-blast after a failure 

closed I–70 near Dumont, CO, in Novem

ber 2019. Representatives from CDOT 

and its contractor viewed the model in a 

video-conferencing meeting to collabora

tively identify and delineate areas of the rock 

slope for removal. CDOT then shared the 

model with the blasting company to use for 

the blast design.

-

-

Minnesota Highway 61 at Mt. Josephine is the site of two rock cuts where rockfall reaches the travel lanes. The 

Minnesota Department of Transportation completed the initial surveying with a total station—ground-based 

survey equipment—followed later with a terrestrial LiDAR survey and point cloud photogrammetry using a UAS. 

© Minnesota Department of Transportation.

Return on Investment

Many State departments of transportation 

are investing in geohazard mapping and 

management programs, as well as the tools 

to provide the input data for processing, 

review, modeling, and decisionmaking. UAS 

is a new option in the geotechnical toolkit 

that is proving highly effective for improv

ing the quality of information, increasing 

safety, and reducing project cost, risk, and 

effort. With better understanding and 

active geohazard management to antici

pate events and proactively plan activities, 

transportation agencies can efficiently apply 

rock scaling and removal or other strate

gies, plan road closures and detours, and 

inform the public of potential impacts with 

advance notice.

-

-

-

Technology of various forms, including 

UAS, is making geotechnical and geohazard 

asset management easier, safer, faster, and 

more economical. A short UAS flight in 

the field can provide data more compre

hensively than would have been previously 

provided by a team of two to three quali

fied geologists or geo-engineers hiking in 

an area and manually mapping for several 

days. UAS can be outfitted with several 

types of imaging sensors for high-quality 

photos, structure-from-motion 3D point 

measurements, and airborne laser scanning.

-

-

Topographic change detection, which 

can be performed more frequently and on a 

smaller scale with UAS, is a transformative 

area of development. This process involves 

comparing two or more temporal datasets. 

Current applications include larger landform and land use changes (such as open pit 

mining), mapping changes in snow cover 

and glaciers, and avalanche detection and 

mapping. There is a significant return on 

investment for geologists, geo-engineers, 

agencies, contractors, the traveling public, 

and taxpayers.

CDOT is using UAS to collect baseline 

images after most rockslides. At small sites, 

the cost of aerial data collection from UAS 

ranges from 10 percent to 20 percent of 

the cost of using a helicopter for similar 

data, depending on location. That cost flips 

when attempting to collect corridor scans: 

the time to collect images of a corridor 

(anywhere from 5 to 10 miles [8 to 16 

kilometers] of highway slopes) results in 

a cost about 200 percent to 500 percent 

of the cost of collecting images using a 

helicopter. However, in CDOT’s experience, 

the accuracy of GPS data in images taken 

from a helicopter has been a concern, and 

the quality of data is appreciably better 

from UAS in both image quality and in the 

ability to process the images.

While CDOT does not have good cost 

data that show the value of the better quality 

of the drone image compared to the photographic images from a helicopter, the agency 
22 | PUBLIC ROADS | SPRING 2021

recognizes that the models are much better 

with UAS-collected images. For CDOT, this 

accuracy has made UAS worth the addi

tional cost when also considering the value 

of the model quality—a model created from 

helicopter-collected images may not provide 

the opportunity to see change detection at a 

desired precision for analysis.

-

An aerial view of a rock slope, and an adjacent highway and rail line, as seen from a UAS used on a New Hampshire Department of Transportation 

research project examining how UAS systems can increase safety and decrease costs of transportation projects. 

© University of Vermont Spatial Analysis Lab.

Geotechnical UAS Operations

State DOTs generally have established an 

organizational structure to facilitate safe and 

efficient UAS operations. Like other UAS 

operators in both the public and private 

sectors, geotechnical UAS users must adhere 

to statutory and regulatory requirements. 

Application limitations include flight time, 

location, weather (high winds or inclement 

conditions), stray currents, and magnetic or 

radio frequency interference. There could 

also be poor global positional control, 

depending on terrain, which would require 

manual flight by the UAS operator.

A key consideration in the specific use 

case of rock slope assessment, given the 

steep and highly variable terrain, is that 

UAS, including flight planning software, 

needs to have terrain-following capabilities. 

In order to have high-quality data from 

LiDAR and photogrammetry, the ground 

sampling distance to the sensor must be 

held constant. Some UAS software can only 

enable flight at a fixed elevation, rather 

than at a fixed distance to ground, which is 

critically important not just for data collec

tion but for safety of UAS in environments 

where the terrain can change rapidly.

-

Data can be captured manually or at pre

determined intervals. Images taken by UAS 

are transmitted back to the remote control

ler, which is typically connected to a mobile 

data collection device for live image process

ing. Once the images have been downloaded 

from the UAS, an extensive array of software 

is available to process the data for different 

purposes, including the following:

-

-

-

Photogrammetry, digital aerial photography, 

and structure from motion— 

Measurements from 

UAS photographs 

combined with correct 

GPS coordinates 

produce extremely 

accurate mapping. The 

flight images obtained 

from the UAS overlap, 

and algorithms within 

the image processing 

software can identify 

related features in each 

image that enables the 

images to be stitched 

together. Dense point 

clouds can be extracted 

from digital aerial 

images, and the density 

of the data can be similar 

to airborne laser scan

ning systems.

-

Digital terrain modeling—

Computer algorithms 

can predict terrain while 

ignoring vegetation; 

digital elevation mod

eling operates similarly 

but includes plant life. 

Both types of modeling 

enable accurate contour 

mapping of features.

-

Airborne laser scanning 

and 3D modeling— 

Points are processed 

using computer software to form a lifelike 

image composed of a 

3D reality mesh model. 

Analysts can rotate the 

images produced by the 

software to provide improved site understanding, to help visualize potential issues, 

and to identify surface anomalies in the 

context of the surrounding elements. The 

3D models differ from photos in that they 

are constructed of 3D information that 

can be employed as a framework to show 

relationships with other spatial data.

The high-quality digital photos obtained 

from UAS, even without the benefits of 

processing, are useful to observe sites from 

otherwise inaccessible vantage points. For 

large events, UAS observations often offer a 

more complete site assessment, providing a 

larger field of view than is typically available 

on the ground. This is particularly advanta

geous when capturing the size and severity 

of the problem is important.

-

Site overview imagery is often invaluable for showing nontechnical 

observers the scope of a landslide, like this one in North Carolina, or 

rockfall event beyond simple cleanup of the travel lanes. 

© North Carolina Department of Transportation.
WWW.FHWA.DOT.GOV | 23

Managing Geohazards in Colorado

CDOT’s Geohazard Program has used 

some form of aerial data collection since the 

1990s. At that time, photographic images 

mainly documented construction activities 

and reviewed oblique, aerial images of steep 

slopes. Recently, the program has been 

collecting baseline images, in the form of 

structure-from-motion and LiDAR point 

clouds, of geohazard corridors and after 

geohazard events.

“With these advances in aerial data col

lection and processing over the past several 

years, the use of UAS has become part of 

the workflow for several of our programs at 

CDOT,” says Stephen Harelson, P.E., chief 

engineer at CDOT.

-

Over time, as additional data are col

lected, change detection will direct investi

gation to specific slopes within in a corridor. 

In combination with other information 

such as UAS rockfall hazard rating system, 

precipitation, temperature data, and change 

detection maps created from surveys, the 

agency’s goal is to establish the likelihood 

of an event and manage risk. Based on an 

informed probability, CDOT can direct 

detailed investigations to those areas of a 

slope that appear most susceptible to failure 

based on data and subject matter expert 

observations and review. It is important to 

note that even the most informed tools and 

techniques still only provide predictions of 

future outcomes.

-

-

The University of Vermont Spatial Analysis Lab produced this 3D point 

cloud from rock slope inspection data for the New Hampshire Department of 

Transportation. The work was done as part of the study on UAS applications to reduce 

cost and increase safety for traffic operations at Crawford Notch State Park. 

© University of Vermont Spatial Analysis Lab.

Derivative products from UAS orthoimagery (small-scale photogrammetry) 

enable transportation agencies to assess earthwork pay quantities. The outlined 

area illustrates the location where slope mesh and retaining anchors will be 

installed. NCDOT and its contractor agreed on this method of measurement 

for payment, decreasing the work required for onsite inspectors. 

© North Carolina Department of Transportation.

Geotechnical Applications 

in North Carolina

For emergency landslide roadway closures, 

the North Carolina Department of Trans

portation (NCDOT) Geotechnical Engi

neering Unit supplies a working plan within 

24 hours, typically with biddable items pro

vided within 72 hours. UAS has facilitated 

the entire process by enhancing four critical 

general project items:

-

-

-

• Fast aerial overview to provide NCDOT 

management and the public with an 

idea of the scale and potential impact 

of the problem.

• Supplemental information from the 

field review to develop the immediate 

mitigation approach, scope, specialty 

geotechnical repair items, quantities, 

and mitigation limits (for potential 

right-of-way and permitting requests 

and requirements). This includes 

information necessary to assess 

slope stability and the potential for 

partial highway reopening prior to 

project completion.

• Periodic overview of progress during 

mitigation to inform management, the 

public, and project inspectors without 

requiring hazardous slope access.

• Initial and final orthophoto, 

topographic, and point cloud 

projections, requiring limited 

hazardous surveying and estimating, 

for final project pay quantities.

NCDOT used UAS on a project along 

I–40 in February 2019. A simple initial 

overview provided general quantities, 

mitigation boundaries, and specialty items 

anticipated from the contractor. The UAS 

images helped observe and document 

project progress and assisted in determin

ing when conditions 

were at the point where 

rockfall barriers could be 

placed and detour travel 

lanes opened.

-

“Aside from the 

established and emerging 

technical applications of 

UAS data,” says D. Clayton Elliott, a geological 

engineer in NCDOT’s 

Western Regional Office, “the ability to 

provide an immediate oblique view of many 

geotechnical projects for concept, safety, 

and construction is now an expected part of 

any project.”

New Applications Evaluated 

in New Hampshire

The New Hampshire Department of Trans

portation (NHDOT) recognized that the 

use of UAS had the potential to reduce costs 

and increase safety for a variety of trans

portation operations. In 2017, NHDOT, 

in partnership with the University of 

Vermont’s UAS team, began a research proj

ect focused on evaluating UAS technology 

for a broad range of case studies including 

rock slope inspection. One case study 

focused on the inspection of a rock slope 

near Crawford Notch State Park in July 

2017. The University of Vermont’s UAS 

team conducted three flights, collecting 

310 photos during a total flight time of just 

over half an hour. The effort had two goals: 

(1) create a high-resolution georeferenced 

point cloud of the rock slope suitable for 

3D modeling to analyze the rock structure, 

and (2) capture high-resolution inspection 

photos of the rock slope to provide multiple 

viewpoints of the rock face.

-

-

-

The team created a 3D model using the 

310 images and digital photogrammetric 

techniques and generated a seamless orthorectified image mosaic. The processing for 

this project took approximately 70 minutes 

to complete. The final report, The Integra

tion of Unmanned Aircraft Systems to Increase 

Safety and Decrease Costs of Transportation 

Related Projects and Related Tasks (FHWANH-RD-26962J), provided several findings 

related to inspection and safety. First, the 

-
24 | PUBLIC ROADS | SPRING 2021

UAS provided a view of the rock slope that 

an inspector would be unable to view from 

the ground. Second, working on the ground 

near rock slopes is not risk-free because of 

potential rock fall and frequent roadway 

traffic. Using UAS generally keeps personnel 

safer from potentially dangerous rock slope 

site conditions. Third, the detailed 3D rock 

slope models provided measurements in 

locations that are unreachable by manual 

measurements, or only accessible using 

potentially dangerous rope-access methods.

Integrating Surface and 

Subsurface Measurements

Surface mapping and imagery from UAS 

can add even greater project value when 

used in combination with other geo

technical tools, such as a borehole tele

viewer. Optical and acoustic televiewers 

can be employed in boreholes to gather 

high-quality information on subsurface stratigraphy as well 

as rock joint and frac

ture orientation.

-

-

-

The Minnesota Depart

ment of Transportation 

(MnDOT) relocated 

a portion of U.S. 53 

between Eveleth and 

Virginia, MN. Future 

iron ore mining adjacent 

to the alignment has 

the potential to create 

excavated rock slopes up 

to 500 feet (150 meters) high, 

in addition to existing slopes, 

requiring characterization of 

rock discontinuities. MnDOT 

used two innovative methods to collect 

the information: down-the-hole televiewer 

logging (both optical and acoustic) and 

photogrammetry using images acquired 

via UAS.

-

Once the team completed the field work, 

they began the joint mapping task. A private 

consulting group, one of MnDOT’s project 

partners, first constructed the models from 

photographs and geo-referenced them using 

a structure-from-motion application and 

contact-free measurement of geological/

geotechnical parameters. The 3D images 

provided comprehensive documentation 

by reconstructing the geometry of the rock 

walls, with measurement of geometric and 

geologic features represented as points, dis

tances, areas, and orientations. The optical 

and acoustic logging was most useful for 

determining the spacing between recurring 

joint-sets (persistence), and the photo

grammetry was only helpful for estimating 

persistence. During construction excavation, 

the persistence was shown to be greater than 

measured using photogrammetry because 

the full extent of joints was obscured by 

talus and vegetation.

-

-

“[We have] found UAS imagery, plus 

the resulting point clouds and meshes, to 

be invaluable in characterizing inaccessible 

rock exposures,” says Dr. Lee Petersen, P.E., 

a principal engineer with one of MnDOT’s 

partners. “We typically capture still pho

tographs to support photogrammetry (to 

make the point clouds and meshes), and 

videos to better understand rock outcrop 

geometry and discontinuities. The point 

clouds are used to extract discontinuity 

location and orientation, and meshes are 

used to extract rock block geometry.”

-

Advanced Geotech

nical Methods 

in Exploration (A-GaME), an initiative of 

round 5 of the Federal Highway Admin

istration’s Every Day Counts (EDC) 

initiative, listed televiewers and UAS as 

highlighted technologies (

-

-

www.fhwa.dot.gov 

/innovation/everydaycounts/edc_5/geotech 

_methods.cfm).

An example image of mapped rock joints from a UAS 

photogrammetry survey along a rock slope at a proposed bridge 

location on the U.S. 53 relocation project in Virginia, MN. 

© 2021 Itasca Consulting Group.

Integrating UAS into Asset and 

Management Programs

UAS provide another tool in the geotechni

cal toolbox for site characterization. Benefits 

include fast response to emergency events, 

decreased data acquisition time, reduced 

cost, greater operational efficiency, improved 

quality, and significantly improved safety at 

hazardous or unstable sites. Transportation 

agencies’ use of UAS has increased signifi

cantly in the past few years, and many State 

DOTs have created new programs related to 

UAS applications. The photos, videos, and 

3D measurements obtained from UAS are 

already improving standards of practice for 

geohazard visualization, change detection, 

risk assessment, informed decisionmaking, 

and hazard/asset management.

-

-

UAS use increases productivity during 

data collection and enables more efficient 

processes and more rapid detection of areas 

of concern. These advantages, combined 

with generating high-quality end products, 

are significant benefits considering the addi

tional value that total data collection costs 

may decrease due to reductions in labor, 

time, and other expenses.

-

UAS technology, coupled with geotech

nical project implementation, provides an 

opportunity for improved practice merging 

surface and subsurface data for 

a significant return on invest

ment and improved risk man

agement—leading to reduced 

costs, improved safety, and, 

perhaps most noticeable to the 

public, fewer traveler delays 

because of unexpected road 

closures from geohazards.

-

-

-

DERRICK DASENBROCK, P.E., D.GE, 

is a geotechnical engineer in FHWA’s 

Resource Center, joining FHWA in 2020 

after working in MnDOT’s geotechnical 

engineering section.

JAMES GRAY, P.E., is a UAS and construction 

technology engineer in FHWA’s Office 

of Infrastructure. He leads FHWA’s EDC-5 

Unmanned Aerial Systems innovation.

BEN RIVERS, P.E., is a senior geotechnical engineer 

in FHWA’s Office of Technical Services. He leads 

FHWA’s EDC-5 A-GaME innovation.

TY ORTIZ, P.E., is the geohazards program manager 

for CDOT.

JODY KUHNE, P.G., P.E., is a regional geological 

engineer in NCDOT’s Geotechnical Engineering Unit 

(GEU). He is a 27-year employee of the NCDOT GEU, 

based out of Asheville, NC.

KRYSTLE PELHAM is an engineering geologist in 

the Geotechnical Section of NHDOT’s Bureau of 

Materials and Research.

For more information, visit www.fhwa 

.dot.gov/innovation/everydaycounts/edc_5 

/uas.cfm or www.fhwa.dot.gov/innovation 

/everydaycounts/edc_5/geotech_methods.cfm 

or contact James Gray at 703–509–3464 

or James.Gray@dot.gov, or Ben Rivers at 

678–613–2807 or Benjamin.Rivers@dot.gov.
WWW.FHWA.DOT.GOV | 25

MAGNETIC FLUX METHODS

DETECTING CORROSION 

IN POST-TENSIONED BRIDGES

FHWA developed and evaluated a proof-of-concept prototype for the magnetic-based, 

nondestructive evaluation technique called the return flux method. Laboratory test results 

prove encouraging in identifying corrosion damage in post-tensioned bridges.

by HODA AZARI and SEUNG-KYOUNG LEE

FHWA is exploring a nondestructive evaluation method to identify corrosion in post-tensioned bridges, which are common in the United States. 

Shown here is the Ringling Causeway Bridge in Sarasota, FL, which needed to have many external post-tensioned tendons replaced.

© Seung-Kyoung Lee.

Post-tensioning in bridge structures offers many benefits. It provides better 

performance during seismic activity; it 

reduces or eliminates shrinkage cracking, 

therefore requiring fewer or no joints; it 

holds cracks tightly together; and it enables 

slabs and other structural members to be 

thinner. Post-tensioning is a constructive 

technology in modern bridge structures 

including segmental box girder bridges and 

cable-stayed bridges. However, the potential 

for corrosion of the steel strands that pro

vide post-tensioning in prestressed concrete 

bridges continues to be a concern.

-

Among nondestructive evaluation 

(NDE) technologies, magnetic-based 

methods have evolved to become promising 

techniques to identify corrosion of metallic 

members embedded in concrete structures. 

An 18-month laboratory study conducted 

at the Federal Highway Administration’s 

NDE Laboratory developed and evaluated 

a proof-of-concept prototype based on the 

return flux method.

Progressive Corrosion of 

Post-Tensioned Tendons

Post-tensioned strands are protected from 

corrosion by a passive film formed in 

cementitious grout, which also serves as 

a physical barrier to water, oxygen, and 

carbon dioxide. However, post-tensioned 

tendons have been discovered frequently to 

contain grout deficiencies such as segregated 

grout and grout voids that can indicate 

high-risk areas of corrosion. In other words, 

corrosion susceptibility of the highly stressed 

post-tensioned strands in the grouted 

tendons increases as grout quality surround

ing the strands decreases.

-

Post-tensioned bridges in the United 

States have experienced tendon failures or 

serious corrosion problems since 1999. On 

November 13, 2009, the Indiana Depart

ment of Transportation (INDOT) closed 

the Cline Avenue (SR–912) bridge over the 

Indiana Harbor Ship Canal after a routine 

inspection revealed significant corrosion of 

the steel tensioning cables and rebar within 

the box girders because of water seeping 

through cracks in the bridge deck. After 

determining that the level of corrosion 

had compromised the bridge’s structural 

integrity beyond repair, INDOT decided to 

permanently close and eventually demolish 

the entire bridge to build a new one.

-

More recently, in June 2020, detailed 
26 | PUBLIC ROADS | SPRING 2021

inspections of the temporarily closed Roo

sevelt Bridge in Stuart, FL, revealed severe 

corrosion and ruptured steel strands in the 

southernmost portion of the 23-year-old 

bridge’s southbound span.

-

In June 2020, an inspection of the temporarily closed Roosevelt Bridge in Florida revealed corrosion and ruptured steel strands. Shown here is the exterior view of the damaged location. 

© Julian Leek / Alamy Live News, Alamy.com.

The return flux magnetizer 

in FHWA’s NDE Laboratory.

Source: FHWA.

Developing an NDE Technique for 

Internal Post-Tensioned Tendons

While tendon corrosion can occur in both 

external and internal post-tensioned tendons, even careful monitoring of internal 

tendons embedded in the concrete may not 

reveal corrosion problems until it is too late.

“As in-service post-tensioned bridges 

containing internal tendons get older, the 

need for reliable ways to assess for this 

type of structure grows. Effective NDE 

methods can help,” says Joseph Hartmann, 

the director of FHWA’s Office of Bridges 

and Structures. “In addition, repairing or 

replacing corroded internal post-tensioned 

tendons is cumbersome or, in many cases, 

nearly impossible compared to similar work 

for external tendons.”

To overcome these problems and dif

ficulties in the field, many agencies have 

employed NDE technologies such as ground 

penetrating radar, impact-echo, ultrasonic 

surface waves, and ultrasonic tomography 

to inspect internal post-tensioned tendons. 

However, current techniques may be able 

to detect some types of grout deficiencies 

but not corrosion of the metal tendon 

components themselves, and therefore 

detecting metal corrosions is difficult 

and inconclusive.

-

Return flux technology can detect corro

sion of steel strands in the internal posttensioned tendons. FHWA’s NDE Labo

ratory, in collaboration with a contracted 

manufacturing company, developed the 

concept of the return flux system based on 

the fundamental principle of magnetic main 

flux: when a ferromagnetic material, such as 

steel strands, is magnetized close to a satu

ration level, the magnitude of the magnetic 

flux going into the material is proportional 

to its cross-sectional area. If corrosion 

damage reduces the cross-sectional area, the 

magnetic flux decreases accordingly. With 

the technology, the internal tendons embed

ded in concrete are magnetized using a 

specially designed yoke-type magnetizer and 

the system measures return flux via multiple 

Hall-effect sensors and search coils.

-

-

-

-

Magnetic main flux is measured after 

wrapping a magnetizer around an exter

nal post-tensioned tendon. In contrast, 

the return flux method uses a two-yoketype magnetizer that is placed on the 

concrete surface directly over an internal 

post-tensioned tendon. After magnetizing 

the buried tendon from one yoke to the 

opposite yoke, researchers can measure the 

magnetic flux on the return yoke.

-

Because concrete is essentially a nonmagnetic material with a relative magnetic 

permeability of unity, it exerts a negligible 

influence on the magnetic measurements 

through the gap that can be clear concrete 
WWW.FHWA.DOT.GOV | 27

cover in actual post-tensioned structures 

plus an air gap between the yoke bottom 

and concrete surface.

The research team conducted an exten

sive numerical simulation to maximize the 

effectiveness of the system in terms of the 

strength of magnetic fields. The final pro

totype consists of a pair of solenoid coils in 

series layout between two yokes. The yoketype solenoid magnetizer was able to exert a 

strong magnetic field through air gaps and 

different concrete cover depths.

-

-

There is an inherent gap between the 

pair of yokes and the concrete over the 

internal tendons, which affects the measure

ment accuracy by leaking flux through the 

air. To address this, the researchers elongated 

the length of the coils to minimize the mag

netic flux leaking in the air by increasing 

resistance in the air between the yokes. The 

team found that the optimal diameter and 

length of the solenoid coils are 4.7 inches 

(11.9 centimeters) and 20.6 inches (52.3 

centimeters), respectively.

-

-

“Condition assessment of embedded 

pretensioned strands and post-tensioning 

tendons in prestressed concrete bridges 

is one of the high priority bridge perfor

mance issues identified by FHWA’s LongTerm Bridge Performance Program and its 

stakeholders—mainly the State DOTs,” 

says Dr. Jean Nehme, the team leader 

for FHWA’s Long-Term Infrastructure 

Performance Team. “Performance of embed

ded prestressing strands and post-tensioned 

tendons will be assessed in detail as part of 

the program. Therefore, this technology will 

be helpful in acquiring the data necessary to 

assess these components.”

-

-

The design of the mockup became cru

cial to the system development. The research 

team considered key features of a typical 

web of segmental box girders containing 

internal tendons. They included sufficient 

concrete cover between a mockup inter

nal tendon and the magnetizer, two types 

of duct material (metal and plastic), and 

horizontal and vertical reinforcing bars. The 

team fabricated two mockup tendons. Each 

could accommodate up to 19 7-wire strands 

with different simulated cross-sectional loss 

and a real anchorage zone composed of 

wedge plate, bearing plate, transition tube, 

and spiral confinement reinforcement in a 

realistic configuration.

-

-

Research Outcomes

The team evaluated various test parameters, 

such as return flux and leaked magnetic 

flux, using strategically placed search coils 

and axial and radial Hall-effect sensors. Test 

results showed that the proof-of-concept 

prototype successfully detected 15.3 percent 

or larger section loss introduced in the 

mockup internal tendons surrounded by 

vertical rebars at 6-inch (15-centimeter) or 

wider spacing and clear concrete cover less 

than 7.4 inches (18.8 centimeters) for metal 

ducts, and 6.4 inches (16.3 centimeters) for 

plastic ducts.

“These initial results are promising,” 

says Cheryl Richter, the director of 

FHWA’s Office of Infrastructure Research 

and Development, “and suggest that the 

return flux method is viable as the basis for 

field-deployable NDE systems to detect 

section loss in post-tensioning strands.”

HODA AZARI is the manager of the NDE Research 

Program and FHWA’s NDE Laboratory at the 

Turner-Fairbank Highway Research Center. She 

holds a Ph.D. in civil engineering from the University 

of Texas at El Paso.

SEUNG-KYOUNG (SK) LEE is the founder and presi

dent of a private consulting firm. Dr. Lee has been 

working on corrosion of different types of reinforc

ing steel and prestressed strands, protective steel 

coatings, cathodic protection, corrosion monitor

ing sensors, and non-destructive evaluation of 

post-tensioned tendons. He is a former chair of the 

Transportation Research Board’s Corrosion Com

mittee and Steel Bridge Coating Subcommittee. 

He holds a Ph.D. in ocean engineering from Florida 

Atlantic University.

-

-

-

-

For more information, contact Hoda Azari 

at 202–493–3064 or Hoda.Azari@dot.gov.

The lab’s bridge mockup is composed of posttensioned tendons and an anchorage zone.

Source: FHWA.
28 | PUBLIC ROADS | SPRING 2021

ALONG THE ROAD

The Volpe Center is assisting the National Park Service with an automated 

shuttle pilot that will provide service in Yellowstone’s Canyon Village, 

located near the scenic Grand Canyon of Yellowstone, shown here.

Source: Volpe Center.

Along the Road is the place to look for information about current and upcoming activities, developments, trends, and items of general interest to the 

highway community. This information comes from U.S. Department of Transportation sources unless otherwise indicated. Your suggestions and input 

are welcome. Let’s meet along the road.

Personnel

‘Mayor Pete’ Buttigieg Begins New Era as 

U.S. Secretary of Transportation

On February 3, 2021, Pete Buttigieg was sworn in as the Nation’s 19th Secretary of Transportation, ushering in a new era focused 

on climate change, racial equity, and economic development. 

Previously, he served two terms as mayor of South Bend, IN. 

After graduating from Harvard University and completing his 

time as a Rhodes Scholar at Oxford University, Buttigieg served 

for 7 years as an officer in the U.S. Navy Reserve, taking a leave 

of absence from the mayor’s office in 2014 for a deployment 

to Afghanistan.

Known widely as “Mayor Pete,” Buttigieg worked to transform South Bend’s future and improve daily life for its residents. 

During Buttigieg’s time as mayor, South Bend’s household income 

grew, poverty fell, and unemployment was cut in half. The city 

established new resources to extend opportunity and access to 

technology for all residents, and launched a “Smart Streets” initia

tive to improve street design. His complete streets strategy helped 

to fuel small business growth along previously neglected corridors, 

and attracted hundreds of millions of dollars in private investment 

in the once-emptying downtown.

-

His leadership helped spark citywide job growth and facilitated 

innovative public-private partnerships like Commuters Trust, a 

benefits program designed to improve the city’s transportation 

experience for workers.

In 2019, he launched his historic campaign for President. 

Throughout 2020, he campaigned for the election of the 

Biden-Harris ticket and served on the advisory board for the 

Presidential transition. In December, he was nominated by 

President-elect Biden to be Secretary of Transportation. He was 

confirmed by the Senate on February 2, 2021, becoming the first 

openly gay person confirmed to serve in a President’s Cabinet.

Public Information and Information Exchange

Watch the EDC-6 Virtual Summit On-Demand

I

n December 2020, more than 2,000 people attended the EDC-6 

Virtual Summit to learn about the new innovations featured in 

the sixth round of the Federal Highway Administration’s Every 

Day Counts program (EDC-6). For anyone who could not attend, 

the sessions, videos, and print material are available on demand.

Watch team leaders lay out their vision for each EDC-6 inno

vation, listen to compelling success stories from agencies already 

using them, explore the virtual exhibit floor to learn about inno

vations from this and past rounds of EDC, and visit the National 

State Transportation Innovation Councils (STIC) Network 

Showcase to learn about more than 200 homegrown innovations 

developed and deployed across the country.

-

-

The agenda for the virtual summit is available at www.fhwa.dot 

.gov/innovation/everydaycounts/edc_6/summit.cfm. To access the 

summit content, which will be available until December 2021, 

register at www.labroots.com/ms/virtual-event/fhwa-everyday-counts 

-6-virtual-summit.

For more information, see the “Innovation Corner” on page 3 

of this issue of Public Roads.
WWW.FHWA.DOT.GOV | 29

USDOT Releases Update to ITS Architecture 

Reference and Toolsets

In late 2020, the U.S. Department of Transportation released the 

Architecture Reference for Cooperative and Intelligent Transporta

tion (ARC-IT) version 9.0, a major update to the Intelligent Trans

portation Systems (ITS) reference architecture and accompanying 

toolsets—the Regional Architecture Development for Intelligent 

Transportation (RAD-IT) and the project-focused Systems Engi

neering Tool for Intelligent Transportation (SET-IT).

-

-

-

ARC-IT and its tools support development of customized 

regional and project architectures to meet local needs while 

enabling safe, secure, and efficient nationally interoperable ITS 

deployments. Changes include enhanced content to support vehi

cle automation informed by research results and stakeholder input, 

including the National Dialogue on Highway Automation, along 

with expanded ITS services.

-

ARC-IT 9.0 expands the Communications Viewpoint with 

re-imagined diagrams along with greater detail on information 

exchanges and identification of suitable standards. As ARC-IT now 

includes services and content contributed by multiple international 

partners, it now supports geographic-awareness to facilitate use in 

multiple regions and to enable U.S. use of internationally contrib

uted services. 

-

Version 9.0 adds several new ITS services (for a total of 150 

services), along with new physical and functional objects. It also 

reintroduces “environmental terminators” that describe system 

boundaries representing the roadway and surrounding physical 

environment that ITS subsystems might sense or need to accom

modate. Users of version 7.1 and earlier might recognize some of 

these; their purpose now is to enable users to better understand the 

relationships between the physical environment and the entities 

that own, operate, and maintain the roadway and vehicles, with 

specific interests associated with highly automated vehicles. 

-

As with version 8.3, ARC-IT 9.0 is available online at 

www.arc-it.net or via a single download that contains most 

ARC-IT content that may be installed locally for offline use. 

The RAD-IT regional and SET-IT project architecture toolsets 

have both been upgraded to accommodate ARC-IT 9.0 along with 

additional standalone features, including the enhanced ability for 

users to exchange information between the two tools.

For more information, visit http://local.iteris.com/arc-it/html 

/whatsnew/whatsnew.html.

Volpe Center Supports First NPS Automated Shuttle Pilot

In May 2021, the National Park Service (NPS) will host its first 

automated shuttle pilot in the Nation’s first national park, Yel

lowstone National Park. The pilot will involve the deployment 

of a low-speed automated shuttle in the Canyon Village area of 

Yellowstone. The project is using funds provided by the FHWA 

Technology and Innovation Deployment Program in concert with 

FHWA’s Office of Federal Lands Highway.

-

NPS has three primary goals for this pilot. First, to enhance the 

visitor experience by facilitating new interpretive opportunities 

and improving mobility assistance. Second, to demonstrate the use 

of autonomous vehicle (AV) shuttle technologies for public use in 

novel operating environments, including rural/remote areas and/

or recreational settings in mixed traffic, and how those outcomes 

could be applied to other public lands. Finally, to identify and 

overcome unforeseen regulatory and organizational barriers of 

emerging mobility technologies.

To date, most automated shuttle pilots have been held in urban 

areas, and the remote setting at Yellowstone will provide NPS and 

AV industry leaders with an opportunity to 

assess the suitability of these technologies for use 

in public lands.

USDOT’s Volpe National Transportation 

Systems Center (Volpe Center) supported the 

NPS pilot through technical assistance, includ

ing the development of a sources-sought request 

to learn more about automated shuttle technol

ogies and a request for quotes that resulted in 

the selection of a private vendor to conduct the 

pilot. Volpe staff have also provided technical 

expertise on automated shuttle technologies to 

NPS staff.

-

-

The Volpe Center will continue to provide 

technical assistance to NPS as pilot planning 

continues. Volpe will also carry out an evalua

tion of the pilot following its completion in fall 

2021. This evaluation will involve assessing the 

performance of the shuttle and its automated 

technology based on a range of metrics to be 

collected during the pilot, including shuttle rid

ership, route performance, battery performance, 

and interventions from the shuttle’s safety 

operator. By assessing the shuttle’s performance 

in Yellowstone’s remote/recreational setting, the 

evaluation will inform potential use cases for 

automated shuttle technologies at other NPS 

and public land sites.

-

-

For more information, contact Travis 

Crayton at Travis.Crayton@dot.gov.

Source: USDOT.
30 | PUBLIC ROADS | SPRING 2021

TRAINING UPDATE

Virtual instructor-led training courses give transportation professionals the opportunity to get the 

training they need, regardless of where they are. The virtual delivery format cuts costs for both hosts 

and participants because conference rooms and travel are not necessary for a virtual training. 

Computer image: © Rawpixel / Shutterstock.com. 

Website: National Highway Institute.

NHI Expert Instructors: Coming to a Computer Near You!

by THOMAS HARMAN and CHRISTINE KEMKER

Virtual learning is a valuable tool in the workforce development toolbox. Self-paced, online courses offer learners the oppor

tunity to train on their own schedule. The National Highway 

Institute’s virtual instructor-led training is conducted via web 

conferences to provide participants with real-time interaction with 

the instructor. The complexity of transportation disciplines makes 

having a live instructor instrumental.

-

Despite the in-person meeting restrictions in 2020, the Nation’s 

transportation industry did not stand still—thus training could 

not wait for in-person gatherings to be widely accessible again. Last 

year, NHI converted 30 of its instructor-led training courses to 

virtual instructor-led training (VILT) courses. Now organizations 

can host a variety of NHI courses virtually, bringing expert instruc

tors to employees for real-time training.

-

The virtual format offers organizations more flexibility in both 

hosting and attending training. “The new virtual delivery format 

allows customers to better target training while reducing costs,” 

says Gay Dugan, a training program manager for NHI. “You can 

host a course just for your staff, or open public seats so peers from 

across the region or Nation can attend.”

Opening seats up to the public helps defray costs while increas

ing valuable collaboration among participants. NHI itself is also 

hosting several training courses as national sessions, with open 

enrollment so that individuals from across the country can register.

-

Sparking the Shift

Since the mid-1990s, NHI has pioneered new ways to provide 

valuable distance learning. From training courses shared on floppy 

disks and course delivery via satellite transmission to HTML5 webbased courses, NHI has been at the forefront of learner-centric, 

accessible training. NHI’s initiative on distance learning led the 

Nation, from creating web-based trainings and web-conference 

trainings first offered in 2003 to blended learning in 2006. Since 

the early 2000s, online trainings have been in high demand and 

NHI has collaborated with industry partners and experts to 

develop a catalog of more than 200 self-paced, web-based trainings 

for transportation professionals.

While the benefits of self-paced learning are evident, and the 

increase in professionals taking web-based trainings demonstrates 

demand, instructor-led trainings have remained a consistent stan

dard for training. Interacting with expert instructors and engaging 

with peers in the transportation industry supports learning com

plex topics and enables participants to receive immediate answers 

to questions.

-

-

Meeting the Industry Need

2020 presented a challenging opportunity, as State departments 

of transportation and other transportation organizations across 

the country had previously scheduled their employees to get 
WWW.FHWA.DOT.GOV | 31

the training they needed to do their jobs through 

instructor-led trainings. With the cancelation of more 

than 400 in-person sessions, NHI stepped up to the 

challenge of providing the needed training virtually.

NHI quickly pivoted and successfully converted its 

high-priority instructor-led trainings to a virtual format. 

NHI scheduled 14 sessions of its Instructor Develop

ment Course for web-conference trainings in order 

to rapidly ramp up and prepare instructors from the 

Federal Highway Administration’s Resource Center and 

NHI to teach in a virtual environment. Concurrently, 

NHI’s training program managers worked with their 

course designers to prioritize and convert content for a 

virtual online training.

-

Stacey Jones, a training program manager at NHI, 

says of the VILT conversion process, “It was awesome to 

see how quickly and easily our partners came together 

when we had to convert face-to-face [trainings] for 

virtual delivery.”

In under 5 months, NHI converted 30 high-demand, 

instructor-led training courses to a virtual format and 

continues to work on converting more.

NHI’s VILTs continue to provide participants with 

the right information and tools needed to enhance 

their skills and support advancement in their respective 

careers. NHI is an International Association for Con

tinuing Education and Training accredited provider, 

which means that most of the converted courses still 

provide continuing education credits upon passing the 

course. These credits can be converted to professional 

development hours for license requirements for State or 

professional organizations.

-

NHI is offering all VILT courses at a discount 

through the end of 2021. Visit NHI’s website to see 

what VILTs are available in your discipline and ask your 

organization to host a session this year.

How to Attend or Host a VILT

Many of these VILT courses are available as national 

sessions—anyone across the country can register and 

attend. Virtual trainings can also be “hosted” by any 

State DOT or transportation agency through the same 

process as regular instructor-led trainings. NHI can pro

vide the training on FHWA’s virtual platform or agencies 

may use their own virtual platform. NHI provides 

instructions, course materials, and expert instructors. If 

an agency would like to open a session up as a regional 

or national session, NHI will work with the organization 

and can even help with marketing. Host requests can 

be submitted directly from the course page—submit a 

request today!

-

NHI invites professionals interested in earning con

tinuing education credits or expanding their career skills 

to visit 

-

www.nhi.fhwa.dot.gov/home.aspx and browse the 

complete digital course catalog, which spans 18 trans

portation program areas.

-

THOMAS HARMAN is NHI’s director.

CHRISTINE KEMKER is a contracted marketing specialist working 

with NHI.

NHI’s VILT Course List

Asset Management

• FHWA-NHI-136002V Financial Planning for Transportation Asset Management

• FHWA-NHI-136106V Introduction to Transportation Asset Management with Workshop

• FHWA-NHI-136106W Developing a Transportation Asset Management Plan

Business, Public Admin, and Quality

• FHWA-NHI-310109 Federal-Aid 101 (FHWA Employee Session)

• FHWA-NHI-310110V Federal-Aid Highways–101

• FHWA-NHI-310119V Writing Effective Program Review Reports: Moving People to Action

• FHWA-NHI-310123V FHWA Basic Contracting Officer’s Representative (COR) Training

Construction and Maintenance

• FHWA-NHI-134001V Principles and Applications of Highway Construction Specifications

• FHWA-NHI-134005V Value Engineering (3-day version)

• FHWA-NHI-134005W Value Engineering (4-day version)

• FHWA-NHI-134005X Value Engineering (5-day version)

• FHWA-NHI-134006V Utility Coordination for Highway Projects

• FHWA-NHI-134037V Managing Highway Contract Claims: Analysis and Avoidance

• FHWA-NHI-134063V Maintenance Leadership Academy

Design and Traffic Operations

• FHWA-NHI-133121V Traffic Signal Design and Operation

• FHWA-NHI-133122V Traffic Signal Timing Concepts

Environment

• FHWA-NHI-142078A Planning and Environmental Linkages 

(PEL), without Implement PEL Activity

• FHWA-NHI-142078V Planning and Environmental Linkages (PEL)

Financial Management

• FHWA-NHI-231033V Public-Private Partnerships (PPP)

Highway Safety

• FHWA-NHI-380077V Intersection Safety Workshop

• FHWA-NHI-380078V Signalized Intersection Guidebook Workshop

• FHWA-NHI-380089V Designing for Pedestrian Safety

• FHWA-NHI-380090V Developing a Pedestrian Safety Action Plan

• FHWA-NHI-380091V Planning and Designing for Pedestrian Safety

• FHWA-NHI-380096V Modern Roundabouts: Intersections Designed for Safety

• FHWA-NHI-380109V Alternative Intersections and Interchanges

Hydraulics

• COMING SOON–FHWA-NHI-135027V Urban Drainage Design

• COMING SOON–FHWA-NHI-135056V Culvert Design

• FHWA-NHI-135095V Two-Dimensional Hydraulic Modeling 

of Rivers at Highway Encroachments

Pavement

• FHWA-NHI-131139V Constructing and Inspecting Asphalt Paving Projects

Structures

• FHWA-NHI-130053V Bridge Inspection Refresher Training

• FHWA-NHI-130053A Bridge Inspection Refresher Training

• COMING SOON–FHWA-NHI-130092V Load and Resistance 

Factor Rating of Highway Bridges

• COMING SOON–FHWA-NHI-130093A Displacement-Based Seismic Design of Bridges

• FHWA-NHI-130125V Tunnel Safety Inspection Refresher ILT

• COMING SOON–FHWA-NHI-130126V Strut-and-Tie Modeling (STM) For Concrete Structures
32 | PUBLIC ROADS | SPRING 2021

INTERNET WATCH

A Modern Tool for Noise Analysis

by AILEEN VARELA-MARGOLLES

Highway traffic creates noise—and sometimes the negative impacts of noise in an area need to be mitigated or minimized. 

To do so, a project team must first conduct a highway traffic noise 

analysis to determine whether noise impacts exist and to consider 

and design potential mitigation measures—noise abatement—to 

reduce those impacts. Designing noise abatement requires understanding basic acoustic principles, regulatory requirements, public 

expectations, and some engineering considerations.

To assist with regulatory compliance related to noise impact 

determinations and noise abatement design, the Federal Highway 

Administration created the Traffic Noise Model (TNM) software. 

The TNM line of software packages has been around for over two 

decades. FHWA released TNM 3.0 in February 2020 and will 

soon release the next version, TNM 3.1.

FHWA worked closely with the Volpe National Transportation 

Systems Center to complete the version 3.1 update. The develop

ment focused on fixing software bugs and addressing feedback and 

feature requests from active TNM 3.0 users.

-

Increased Functionality

TNM 3.1 now includes an installer, parallel processing of receivers, 

and removal of the database saving structure. The updates should 

decrease the memory usage and runtimes of the software.

TNM 3.1 corrects some minor acoustical calculation issues 

from TNM 3.0, although there have been no changes to the 

underlying acoustical assumptions or metrics since the last release. 

The developers updated the data model for TNM 3.1 with 

improved error checking and error handling compared to TNM 

3.0, so that version 3.1 can provide results for project models that 

would have errored out in TNM 3.0.

TNM 3.1 also offers an improved user interface and data 

connections. These changes were made in response to detailed 

user feedback regarding important functionality and data visibility 

required to conduct a highway traffic noise analysis on a typical 

project. For example, the Barrier Design Table now shows sound 

source contributions by barrier segment and offers the ability to 

filter and sort the data in the table. TNM 3.1 also enables the 

user to import existing TNM model files that include coordinate 

systems, projections, and adjustments. For more information 

regarding the updates, please see the Release Notes and TNM 3.1 

Fact Sheet at www.fhwa.dot.gov/environment/noise/traffic_noise_model 

/tnm_v31/index.cfm.

To further expand TNM’s functionality, FHWA is developing a 

Noise Screening Tool that allows simplified inputs and outputs to 

enable users to determine the likelihood of noise impacts occurring 

before engaging in a full-scale noise analysis.

Ongoing Maintenance and Future Enhancements

FHWA has set a target schedule to provide annual or semiannual releases of TNM. This will enable the development team 

to respond quickly to user requests, enhancement ideas, and new 

software programing protocols. The TNM 3.0 acoustics and TNM 

3.1 functionality will be used to update the Roadway Construc

tion Noise Model (RCNM). In addition, the team is evaluating 

whether it is possible to integrate TNM and RCNM into a single 

highway noise model.

-

FHWA continues to engage the user community through 

training, regular email updates, and meetings. For further 

information on using TNM, visit the instructional demonstration 

videos on the TNM playlist at www.youtube.com/playlist?list=PL5 

_sm9g9d4T3naH9knm5E6SZUpmI_QD3y. The FHWA Resource 

Center also offers training via a multi-day course. The lessons are 

currently instructor-led, but virtual.

For more information, contact Aileen Varela-Margolles at 

a.varela-margolles@dot.gov.

AILEEN VARELA-MARGOLLES is an environmental specialist on the Air Quality 

and Noise Team in FHWA’s Office of Environment, Planning, and Realty.

This screenshot of the TNM 3.1 

Graphical User Interface displays 

the various areas and windows 

available for the user to input 

and review data. The main 

window is a streetview map 

of the example project area.

Source: FHWA.
WWW.FHWA.DOT.GOV | 33

COMMUNICATION PRODUCT UPDATES

Below are brief descriptions of communications products recently developed by the Federal Highway Administration’s Office of Research, 

Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, 

limited copies of the communications products are available from FHWA’s Research and Technology (R&T) Product Distribution Center (PDC).

Compiled by LISA A. SHULER of FHWA’s Office of Corporate Research, Technology, and Innovation Management 

When ordering from NTIS, include the NTIS publication number 

(PB number) and the publication title. You also may visit the 

NTIS website at www.ntis.gov to order publications online. Call 

NTIS for current prices. For customers outside the United States, 

Canada, and Mexico, the cost is usually double the listed price. 

Address requests to:

National Technical Information Service 

5301 Shawnee Road 

Alexandria, VA 22312

Telephone: 703–605–6050 

Toll-free number: 1–888–584–8332 

Website: www.ntis.gov 

Email: customerservice@ntis.gov

Requests for items available from the R&T Product Distribution 

Center should be addressed to:

R&T Product Distribution Center 

Szanca Solutions/FHWA PDC 

700 North 3rd Avenue 

Altoona, PA 16601 

Telephone: 814–239–1160 

Fax: 814–239–2156 

Email: report.center@dot.gov

For more information on R&T communications products available 

from FHWA, visit FHWA’s website at www.fhwa.dot.gov, the FHWA 

Research Library at www.highways.dot.gov/resources/research-library 

/federal-highway-administration-research-library (or email fhwalibrary 

@dot.gov), or the National Transportation Library at ntl.bts.gov (or 

email library@dot.gov).

Leveraging Augmented 

Reality for Highway 

Construction 

Publication Number: FHWAHRT-20-038

Augmented reality (AR) is 

an immersive technology 

combining computergenerated information with 

real-world imagery in real 

time. AR enhances the user’s 

perception of reality and 

enriches information content. Challenges in highway 

construction management 

and field operations include 

the lack of real-time and integrated information, gaps between 

planned solutions and practical implementations, quality assur

ance, and effective project communications. Three-dimensional 

(3D) model-based design and construction workflows are becom

ing more common on highway projects, and the Federal Highway 

Administration is promoting these and other innovations through 

its Every Day Counts program and Building Information Model

ing efforts.

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The increased use of 3D model-based workflows and rapid 

advancement in computer interface design and hardware make AR 

a tool for overcoming these construction challenges. Enriched content can help project managers and engineers deliver projects faster, 

safer, and with greater accuracy and efficiency. This study focused 

on documenting current AR technologies and applications, with 

an emphasis on the state of the practice for using AR technologies 

in design, construction, and inspection applications for highways, 

and includes a literature review and interviews with researchers 

and vendors.

The publication is available at www.fhwa.dot.gov/publications 

/research/infrastructure/pavements/20038/20038.pdf.

Utilizing Mobile Ad Hoc Networks to Enhance Road Safety 

Publication Number: FHWA-HRT-20-046

Analyses by the National 

Highway Traffic Safety 

Administration concluded 

connected vehicle innova

tions could reduce crashes, 

injuries, and fatalities by 

50 percent. There are places 

and times, however, where 

there will be a need to sup

plement connected vehicle 

systems—for example, in 

rural areas where there may 

not be enough traffic for 

connected vehicle systems to 

be viable, or during events 

when crowds may overwhelm systems working well 

during normal operations.

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FHWA’s Exploratory Advanced Research Program supports 

studies investigating the use of mobile ad hoc networks (MANETs) 

to enhance road safety for all users. MANETs are a way to commu

nicate on the fly with available hardware and software. MANETs 

require minimal infrastructure and can be created autonomously as 

desired. They have been used primarily in military applications and 

in disaster relief efforts, but have not yet been used for transporta

tion safety.

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34 | PUBLIC ROADS | SPRING 2021

One scenario involves smartphones from nonmotorized trav

elers directly sending automatic, periodic geographical broadcast 

messages via a mobile application to nearby vehicles, which, in 

turn, send the information to following vehicles. This method 

eliminates the need to ping other vehicles about the nonmotorized 

traveler’s location and alerts vehicles to their location more quickly. 

-

Researchers at the University of Virginia are exploring how to 

deploy MANETs in areas and scenarios with less infrastructure, 

such as when pedestrians and bicyclists cross at the mid-block and 

in more rural or remote settings. At the University of Wisconsin–

Madison, researchers look to harness MANETs to alert vehicles 

to pedestrian and bicyclist crossings at intersections through a 

mobile application.

The publication is available at www.fhwa.dot.gov/publications 

/research/ear/20046/20046.pdf.

Evaluation of Holes Fabricated Using Plasma Arc Cutting 

Publication Number: FHWA-HRT-20-056

This report documents 

fatigue and tensile test results 

of steel plates with round 

holes fabricated using plasma 

arc cutting. Bridge owners, 

designers, and fabricators 

have shown interest in using 

plasma arc cutting as a more 

economical alternative to 

traditional hole fabrica

tion methods. However, a 

lack of experimental data 

demonstrating the behavior 

of plasma-cut holes under 

fatigue and tensile load

ing has hindered their use 

in steel bridge design and 

fabrication. FHWA initiated 

the study to categorize the fatigue and static tension resistance of 

plasma-cut holes in steel bridge members.

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-

Modern plasma-cutting equipment and techniques can produce 

high-quality holes more economically than drilling and punching. 

However, design and construction specifications from the Ameri

can Association of State Highway and Transportation Officials do 

not permit the use of plasma-cut holes in primary bridge members 

because of a lack of experimental data demonstrating their fatigue 

and tensile strength. Additionally, it is uncertain if holes fabricated 

using plasma arc cutting meet the AASHTO requirements for 

accuracy of hole size.

-

This research establishes the design fatigue resistance and 

assesses the fracture behavior of steel members with plasma-cut 

holes. Researchers evaluated multiple plasma-cutting processes. 

Results showed that the fatigue resistance of plasma-cut holes is 

lower compared to current hole-making methods. The researchers 

found that open holes fabricated using plasma arc cutting are an 

AASHTO category E fatigue detail, representing lower fatigue 

resistance compared to drilled or punched holes. Tensile testing 

showed certain plasma-cutting processes could cause brittle failure 

modes in tension members with plasma-cut holes.

The publication is available at www.fhwa.dot.gov/publications 

/research/infrastructure/structures/bridge/20056/20056.pdf.

Learning About Driver and Pedestrian Behaviors 

Through Connected Simulation Technology 

Publication Number: FHWA-HRT-20-059

  As the Nation’s roadways

increase in connectivity 

and complexity, a challenge 

emerges to maintain road 

safety and mobility for all 

roadway users. Examining 

how vehicles and pedestri

ans share the road is one 

key way to improve road 

safety, especially considering 

increased pedestrian deaths 

by motor vehicle crashes. 

In 2018, there were 6,283 

reported pedestrian fatalities 

due to car crashes, the most 

since 1990. This report 

provides a description of 

the research carried out to 

improve the understanding of connected simulated technology 

and how to expand the study of interactions between drivers and 

pedestrians, impacting the creation of technologies involving safety 

and mobility.

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FHWA’s Exploratory Advanced Research Program has been supporting research examining simulated traffic interactions between 

drivers and pedestrians to better understand how they commu

nicate with each other and the resulting impacts on driver and 

pedestrian behaviors. The University of Iowa conducted a research 

project using real-life drivers and pedestrians along with simulated 

vehicles and pedestrians in a connected driving simulation. The 

researchers successfully created a connected simulation environ

ment, linking a pedestrian simulator and a driving simulator by 

bridging differing software systems—a large technical challenge of 

the project.

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Based on the connected simulation technology, the researchers 

explored the relationship between glances and gestures pedestri

ans may make toward oncoming traffic as they attempt to cross a 

roadway. This study was facilitated using 3D avatars, which the 

Iowa team customized for the research project. The project resulted 

in the development of mixed-mode technology with connected 

driving and pedestrians through the use of graphical avatars, repre

senting the live actions and movements of drivers and pedestrians.

-

-

Additionally, the study yielded new methods of scenario control 

and data analysis suited for multiparticipant simulation research. 

Although participants stated that most of the time they could 

not distinguish the real participants from the simulated ones, the 

COMMUNICATION PRODUCT UPDATES
WWW.FHWA.DOT.GOV | 35

results suggest real study participants do behave differently with 

each other than with simulated pedestrians and vehicles.

The publication is available at www.fhwa.dot.gov/publications 

/research/ear/20059/20059.pdf.

Coating Performance on Existing 

Steel Bridge Superstructures 

Publication Number: FHWA-HRT-20-065

Steel corrodes when exposed 

to moisture and oxygen. 

If left unprotected, some 

steel used in highway bridge 

superstructures is highly 

susceptible to corrosion 

when exposed to the 

environment. The corro

sion process is significantly 

accelerated in the presence of 

salts. Corrosion on highway 

bridges is predominantly 

caused by chloride ions from 

either deicing salts or natural 

chlorides present in cer

tain environments.

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This study evaluated 

the performance of four 

coating systems applied on chloride-contaminated steel substrates. 

The purpose of the study was to identify coating systems that can 

provide extended service life for steel bridges with minimal surface 

preparation at a much-reduced cost. The study helps estimate the 

amount of chloride contamination coating systems can tolerate 

without significant premature failure.

The chloride contamination levels tested in this study were 0, 

20, and 60 micrograms per cubic centimeter. The coating systems 

tested were two three-coat systems (one with inorganic zinc-rich 

primer and the other with organic zinc-rich primer), a two-coat 

system with carbon nanotubes in its zinc-rich primer, and a onecoat system of high-ratio calcium sulfonate alkyd. Coated panels 

were exposed to two conditions: accelerated laboratory testing and 

outdoor natural weathering. The three-coat systems had the best 

corrosion protection performance among the tested specimens. 

The inorganic zinc primer performed slightly better than the 

organic zinc primer. The two-coat system demonstrated the highest 

adhesion strength over all levels of chloride contamination.

The publication is available at www.fhwa.dot.gov/publications 

/research/infrastructure/structures/bridge/20065/20065.pdf.

To Alert or Assist: Comparing Effects of Different 

Lateral Support Systems on Lane-Keeping 

Publication Number: FHWA-HRT-20-068

Road-departure crashes, in 

which a vehicle inadver

tently drifts off the road, 

are among the most severe 

types of crashes, making up 

37 percent of highway fatal

ities. Lateral support systems 

have the potential to reduce 

road-departure crashes by 

decreasing the probability 

that a vehicle will leave its 

intended travel lane. Two 

lateral support systems on 

the market are lane-departure 

warning (LDW) and 

lane-keeping assist (LKA). 

LDW systems issue a visual, 

audible, or haptic warning 

to alert the driver when the vehicle has crossed a lane boundary. 

LKA systems actively move the vehicle back into its lane by either 

applying steering torque or light differential braking.

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This publication describes an experiment examining the effect 

of lateral support systems on driving behavior and user acceptance 

of lateral support systems. The research team used a driving sim

ulator to compare lane-keeping behavior when drivers controlled 

the vehicle without lateral assistance (manual control) or were 

assisted by LDW or LKA systems. The goal of the study was to 

assess the effect of each type of lateral support system on drivers’ 

lane-keeping ability in different situations and examine driver 

acceptance of lateral support technology.

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This study assessed the influences of lateral support systems 

on lane-keeping. Participants were divided into three conditions: 

LDW, LKA, and manual driving. The experiment used simu

lated wind gusts to induce lane departures throughout the drive. 

Participants in the LDW condition spent less of the drive outside 

of their lane, returned to their lane more quickly when a lane 

departure occurred, and held a more constant position while in 

their lane. Lane-keeping for drivers in the LKA condition did not 

match those in the better lane-keeping LDW condition, but the 

group showed reduced lane-departure durations relative to those in 

the manual driving condition. Participants in the manual driving 

condition also showed reduced travel speeds relative to those in 

the LDW or LKA conditions, suggesting that the difference in 

lane-keeping was not due to a lane-keeping/speed tradeoff. In fact, 

participants in the LKA condition maintained similar levels of 

lane-keeping compared to participants in the manual condition 

while driving more quickly, indicating LKA improved drivers’ 

lane-keeping ability. The findings speak to the potential usefulness 

of lateral support systems for reducing lane departures.

-

The publication is available at www.fhwa.dot.gov/publications 

/research/safety/20068/20068.pdf.
NATIONAL WORK ZONE 

AWARENESS WEEK April 26–30, 2021

Work zones play a critical role in the 

preservation and enhancement of 

our Nation’s roadways. However, 

changes to traffic patterns and rights 

of way due to work zones, combined 

with the presence of workers and 

the frequent movement of work 

vehicles, may lead to crashes, 

injuries, and fatalities.

It’s important for everyone to do their part to be 

safe. To protect field workers and all road users, 

follow these tips for traveling safely through 

work zones:

• Know before you go

• Stay alert and obey 

the roadway

• Watch for workers

• Watch for sudden stops

• Slow down

• Use caution 

around large 

vehicles

For more information and resources, visit the FHWA Work Zone Management 

website at www.fhwa.dot.gov/workzones and the National Work Zone 

Safety Information Clearinghouse at www.workzonesafety.org.
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