FHWA R&T Now

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Do Unmanned Aerial Systems Make Bridge Inspections Safer?

According to the FHWA, the National Bridge Inspection Standards (NBIS) require safety inspections 

every 24 months for bridges exceeding 20 feet in length on public roads. With hundreds of 

thousands of bridges across the country, State departments of transportation (DOTs) can benefit 

from a process which is safer, more efficient, and saves money. 

With the advancement of technology, bridge inspection is becoming more efficient, and safer, 

without sacrificing quality and completeness. The use of unmanned aerial systems (UAS) can provide 

a lower cost and easier-to-use method to inspect bridges and roads. UAS can fly into locations that 

remain difficult to navigate, such as the undersides of bridge decks, along tall columns, and other 

difficult-to-see and reach areas. 

The systems are equipped with sensing devices, cameras, and GPS capabilities to enable 

autonomous and repeatable flight, obstacle avoidance, and inspection from a safe distance. In a 

March 2018 survey, reported in the TechBrief, Use of Small Unmanned Aerial Systems for Bridge 

Inspection, by the American Association of State Highway and Transportation Officials (AASHTO), 35 

of 44 reporting State DOTs indicated that they have experience deploying UAS in some capacity.

James Gray of the FHWA said, “We can take care of visual documentation with the UAS and let the 

inspector focus on the things the UAS can't do, which makes bridge inspections more efficient.” He 

added that, “MN DOT on average finds that UAS can decrease inspection costs by about 40 percent

through this increased efficiency.” 

The public can also benefit from UAS use with reduced lane closure durations, saving precious time. 

Bridge inspectors will also benefit from UAS technology as it will reduce the time spent in high-risk

work zone lane closures. Additionally, UAS make the following easier: preplanning activities, 

capturing visual evaluations from difficult-to-access locations, and providing ongoing and repeatable 

monitoring of known defects. State DOTs may also reduce costs. 

For more information about the program, contact James Gray at james.gray@dot.gov.

September/October 2020

A news update of research, technology, and development from the U.S. Department of Transportation (USDOT), 

Federal Highway Administration (FHWA)

FHWA R&T Now

A news update of research, development, and technology (RD&T) from the U.S. Department of Transportation (USDOT), 

Federal Highway Administration (FHWA).

UAS units flying near bridge area. Source: FHWA.
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OPERATIONS

Alleviate Freeway Bottlenecks at Congestion 

Points

Merging, diverging, and weaving areas on freeways 

are major bottlenecks that cause ongoing

congestion issues. An Office of Operations 

Research and Development (R&D) study evaluated 

five alternative infrastructure designs for 

application at bottleneck areas. The final report, 

Alternative Designs to Alleviate Freeway 

Bottlenecks at Merging, Diverging, and Weaving 

Areas, was published in May 2020. The report may 

be useful for State and local DOTs interested in 

exploring innovative methods to manage their 

facilities more effectively.

The primary research tool used for the study was 

sensitivity analyses via microscopic traffic 

simulation, also known as microsimulation. The 

alternative designs developed and evaluated 

through this research effort are split merge points, 

managed lanes on the right-hand side, mainline 

metering, coordinated ramp metering, and speed 

optimization via traffic calming devices. 

Coordinated ramp metering did not show 

significant additional benefits beyond 

conventional asservissement lin’eaire d'entr’ee 

autorouti‘ere, also known as ALINEA, metering.

ALINEA is a relatively new local traffic-response 

strategy to address ramp metering. The strategy is

based on a feedback structure and is derived using 

classical automatic control methods. Speed 

optimization showed excellent benefits but only 

during narrow ranges of traffic congestion. 

Mainline metering also showed reasonably good 

benefits but could be challenging to implement. It 

is conceivable that speed optimization and 

mainline metering could produce more favorable 

benefit-cost ratios if implemented via connected 

and automated vehicle (CAV) technologies. 

Results indicate that the split merge design, and 

positioning of managed lanes on the right side of 

the freeway, are two unrelated designs that 

showed excellent promise (in terms of benefit-cost 

ratio). The split merge and right-side managed lane 

designs produced excellent benefits without the 

need for CAV technologies.

For more information, contact Rachel James at

rachel.james@dot.gov.

Federal Transit Administration (FTA) Gets New 

Director from FHWA

The FTA’s Office of Research, Demonstration, and 

Innovation (TRI) hired former FHWA employee 

Mohammed Yousuf. Yousuf joins the FTA with 

almost 10 years of experience at the FHWA’s 

Turner-Fairbank Highway Research Center. Yousuf 

was previously Program Manager for one of the 

USDOT’s high-profile strategic programs, the $60M 

Automated Driving System (ADS) Demonstration 

Grants. While at the FHWA, he also created, 

launched, and implemented the Accessible 

Transportation Technology Research Initiative 

(ATTRI).

Yousuf joins the FTA’s management team as the 

new Director for the Office of Infrastructure and 

Asset Innovation (TRI-20). His first day in his new 

position was June 22, 2020, and his new 

responsibilities include managing the FTA’s 

research portfolio on safety, infrastructure, and 

asset management, as well as oversight of the bus 

testing program where he led a seasoned team of 

experienced program managers and engineers.

Yousuf also spent time during his career at Chrysler 

Corporation and General Motors. He holds a BS in 

Electronics and Communication Engineering, and 

an MS in Computer Engineering. 

SAFETY

FHWA Crashes into the Future

How does an agency develop and share its Federal 

Outdoor Impact Laboratory (FOIL) crash tests with 

an online audience in a virtual environment? The 

solution may not be as easy as taking a video on a 

cell phone and streaming it live. Sure, a cell phone 

can take a video of a vehicle crashing into a barrier,

but a video does not show the purpose of the test 

nor enough detail to help with a solution. 

A crash test is destructive testing performed on 

vehicles to ensure safe design standards in 

crashworthiness. A challenge to presenting crash 

tests across the Internet is that the equipment 

used for crash tests is not actually intended to be 

used in this way. 

Traffic Congestion Pattern Source: FHWA.
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Cameras used in crash tests are not like personal 

video cameras. Crash test cameras are designed 

to withstand G-Forces experienced during crash 

events. The high-resolution cameras can capture 

more frames per second than commercial 

cameras and can record up to 1,000 frames per 

second—while commercial cameras capture 60 

frames per second. All this detail translates into 

extremely large files.

During a crash test, several video views (7 to 9) 

are recorded at very high frame rates—500 to 

1,000 frames per second. The video files are 

recorded internally to each camera, but then the 

extremely large files must be downloaded 

through a high-speed, wired connection, which 

can take up to 30 minutes. 

According to FOIL Manager Eduardo Arispe of the 

FHWA, “Although we are not currently able to use 

our cameras to webcast the tests in a live stream, 

laptops with wireless connections and internal 

cameras do allow us to show several different live 

views of the test. The videos from the “official” 

seven to nine cameras are later emailed to the 

audience after those files have been downloaded 

and converted.”

Arispe continued, “And most important, the 

videos would not show the whole picture.” A 

crash test is not composed of just videos. Crash 

tests also rely on sensor equipment and heavy 

data analysis to help researchers find the reasons 

for the problem. In combination with the video, 

pre- and post- vehicle measurements, and sensor 

data will be compiled and studied to build a 

three-dimensional model that will be put through 

a variety of scenarios. 

And finally, the scenarios will be analyzed to find a 

solution. Even though FHWA is testing various 

equipment to bring a live video stream to the 

Internet, the video is only part of the crash test. 

In the words of famous radio personality Paul 

Harvey, and then there is “the rest of the story.”

For more information, contact Eduardo Arispe at 

eduardo.arispe@dot.gov.

Evaluation of Aesthetically Treated Crosswalks

FHWA has received many requests to install 

colored aesthetic treatments within crosswalks. 

However, when changing recognizable 

transportation devices such as crosswalks, many 

questions would need to be answered to ensure 

the safety of the traveling public. Would different 

colors be distracting for drivers? Would the colors 

be recognized as a crosswalk by pedestrians and 

drivers? Would the colors be as effective as white 

pedestrian crosswalk markings when seen from a 

distance? These types of questions and many 

others would need answers before implementing 

changes that might affect safety.

The Office of Operations, Manual on Uniform 

Traffic Control Devices (MUTCD) Team and the 

Office of Safety R&D are collaborating on the 

research study Evaluation of Aesthetically Treated 

Crosswalks. The study focuses on a rainbow color 

pattern since there is significant interest in its use 

with crosswalks.

Through closed-course studies, this project will 

evaluate the impact that aesthetic treatments have 

on motorists’ and pedestrians’ recognition and 

behavior at crosswalks, including pedestrians with 

low vision. The study will also attempt to 

determine what conditions or aspects of the 

aesthetically treated crosswalks impact road user 

recognition and behavior.

Road users include drivers and pedestrians (with 

normal and low vision). The project began on June 

1, 2020 and is scheduled for completion by May 

31, 2022. 

The results of the study will identify not only the 

impact of aesthetically treated crosswalks on road 

user’s recognition and behavior, but also what 

conditions or aspects of the aesthetically treated 

crosswalks have the most impact. This will allow 

the FHWA to identify the crosswalk designs that do 

not impact recognition and behavior, if any exist. 

These results will also inform FHWA’s future 

decisions on aesthetically treated crosswalks.

For more information, contact Ann Do at 

ann.do@dot.gov. 

Full-Scale Crash Test Source: FHWA.
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INFRASTRUCTURE

Monthly Nondestructive Evaluation (NDE)

Program Webinars

The NDE Program hosts monthly webinars that 

focus on bridge, tunnel, and pavement 

applications. The goal of the webinars is to provide 

education on how different States use NDE 

technologies, their current practices, challenges, 

added value, policies, future visions, and 

recommendations to other States. 

The webinars are held the last Monday of every 

month at 1 p.m. (EST) and provide a platform for 

the State DOTs to exchange knowledge and 

innovation in highway infrastructure, as well as 

inform researchers, technology providers, and 

industry representatives about different States’ 

current practices and policies. Additionally, the 

webinars share States’ challenges and future 

directions regarding use of NDE for condition 

assessment of highway assets. 

The following topics will be covered in upcoming 

meetings:

September – Minnesota DOT will be 

talking about an advanced NDE 

technology that can provide continuous 

and complete roadway information by 

integrating state-of-the-art hardware for 

pavement data collection and advanced 

software for processing, synchronization, 

and visualization of the data. The 

advanced technologies can provide 

information on:

• Transversal and longitudinal 

rutting profiles.

• Layer thickness.

• Layer strength and moduli.

• Point-cloud laser transversal and 

longitudinal.

• Roughness measurements.

• Pavement surface imaging, and 

video logging data.

• Moisture monitoring using GPR 

Frequency Response.

• Pavement cross fall.

• Pavement settlement.

• Ditch and shoulder failures.

October - Indiana DOT will discuss how they use 

NDE for bridge deck maintenance and to support 

their bridge management program.

November – Florida DOT will present how they use 

NDE to detect the location and severity of 

delamination in pavements.

For more information about attending these 

webinars, contact Hoda Azari at 

hoda.azari@dot.gov.

RECENT RESEARCH PUBLICATIONS

Infrastructure

• Asphalt Binder and Mixtures Laboratory (ABML) 

Look-In

• Applying Raman Spectroscopy to Study AlkaliSilica Reaction Gels

Safety

• TechBrief: Safety Evaluation of Flashing Yellow 

Arrows at Signalized Intersections

• High Friction Surface Treatment (HFST) Quick 

Reference – June 10, 2020

• Alternative Designs to Alleviate Freeway 

Bottlenecks at Merging, Diverging, and Weaving 

Areas

RECENT PERIODICALS

Innovator September/October 2020

In this issue: Get Ready for Every Day Counts 

Round Six. Agencies CHANGE Hydraulic Modeling 

Approach. Playing the A-GaME to Improve 

Reliability and Reduce Risk. Innovation Synergy. 

Iowa Creates Virtual Public Involvement Tool. 

States Innovate. FHWA Innovation Conversation.

The September/October 2020 issue is available at: 

https://www.fhwa.dot.gov/innovation/innovator/i

ssue80/. 

EDC News September 10, 2020

The September 10, 2020, issue of EDC News was 

released. The articles are as follows: Innovation of 

the Month: Collaborative Hydraulics: Advancing to 

the Next Generation of Engineering (CHANGE). 

GDOT Shares Lessons Learned from Virtual Public 

Information Open House. Getting "TUF" on 

Transportation Funding Gaps.

The September 10, 2020, issue is available at: 

https://www.fhwa.dot.gov/innovation/everydayco

unts/edcnews/20200910.cfm.

Office of Planning, Environment, and Realty (HEP): 

What’s New

Under the leadership of the U.S. Transportation 

Secretary, Elaine l. Chao, HEP serves as FHWA’s 
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advocate and national leader for environmental 

protection and enhancement, comprehensive 

intermodal, and multimodal transportation 

planning, and for fair and prudent acquisition and 

management of real property.

The latest HEP updates are available at: 

https://www.fhwa.dot.gov/hep/whats_new/

Public Roads Summer 2020

The Summer 2020 issue of Public Roads magazine 

is now available on the FHWA website. In this

issue: Can Augmented Reality Address Highway 

Construction Challenges? CARMASM: Enabling 

Collaboration and Ensuring Safety in Freight 

Operations. Going-to-the-Sun Road: Construction 

and Restoration. Everybody Wins. Facing Volcanic 

Challenges. 

The summer issue is available at: 

https://www.fhwa.dot.gov/publications/publicroa

ds/20summer/index.cfm.

For more information or to submit an article, 

contact Maria Romstedt at 

maria.romstedt@dot.gov.

LINKS

Turner-Fairbank Highway Research Center: 

https://highways.dot.gov/research/

Resource Center: 

www.fhwa.dot.gov/resourcecenter/

National Highway Institute: 

www.nhi.fhwa.dot.gov/home.aspx

ABOUT FHWA R&T NOW

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technology, and development from the U.S. 

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