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TRANSCRIPT
Digital Billboards on
Highways: A Bright
Future?
TRB Human Factors Workshop
January 13, 2008
Jerry Wachtel, The Veridian Group, Inc.
Presiding
Section 1:
Introductions
Interests
Desired Outcomes
Section 2:
A Brief History
A Brief History of Regulation
Highway Beautification Act
Bonus States
Billboards vs. On-Premise Signs
Commercial Electronic Variable Message
Signs
(CEVMS)
Section 3:
Functional and
Technological Changes
Over Time
Functional and Technological
Changes Over Time
From paint
To paper
To vinyl
To Lamp/Bulb Matrix
To Tri-Vision
To LED = DBBs
What Makes DBBs Unique?
Brightness – especially at night
Size potential – one sign is 90 x 65 ft; 165 ft
high
Compelling photo-realistic/broadcast
imagery
Intermittency and image change at will
Potential for message sequencing
Potential to sequence multiple signs in range
Potential for interactivity with driver
Why are DBBs Causing Safety
Concerns?
Their brightness at night:
Can overpower driver’s ability to see TCDs, brake lights
Can cause glare – temporary blindness
Can attract eye gaze from enormous distances
High visual fidelity can attract and hold attention
longer
Periodic image change can have visual effect of
flashing
Messages can be “sequenced” to hold attention
longer
No acclimation; displayed message can be always
novel
Targeted messages can be very distracting – e.g.
current score of the game; win concert tickets to
performer you are listening to right now!
How Are Safety Concerns
Manifested?
Driver distraction increasingly recognized as safety concern
Particularly on urban freeways with high speed, high volume
traffic
Can cause traffic delays as drivers slow to read messages
Can attract drivers’ gaze farther away, repeated looks, longer
time
Image quality plus interest can compel longer glances
Frequently changing messages can compel more glances
Sequenced messages can hold gaze until entire message can be read
Brightness and flashing appearance captures attention at greater
distances
Multiple DBBs in close proximity exacerbates these concerns
Interactive signs, like games, may require action from driver
“to play”
FHWA Treats DBBs Same as
Tri-Vision Signs
Why?
Compared to DBBs, Tri-Vision has:
Only 3 repeating messages
No unusual brightness
No instantaneous update
No high visual fidelity
No extraordinary size
Perhaps we can explore this issue later today
Section 4:
Early Research
Early Research History – thru 1960
Lauer, Kotvis, McMonagle
Minnesota and Michigan
Rusch
Ady
Faustman
Madigan Hyland
Research – The Middle Years
1960-1990
Johnston and Cole
Holahan
Boston TeleSpot
Milwaukee County Stadium
Lehtimaki
AUTHORS DATE TYPE OF
STUDY
KEY FINDINGS
MN Dept of Highways 1951 Post-hoc accident review More BBs per mile = more crashes
Intersections with 4 or more BBs = 3x crash rate
Rusch 1951 Post-hoc accident review Higher crash rate in zones with BBs than not
“Inattention” crashes predominate in BB zone; but not in others
MI State Hwy Dept 1952 Post-hoc accident review BBs showed no general correlation with crashes; illuminated BBs
showed “appreciable association” w/crash locations
Lauer & McMonagle 1955 Simulator No relationship
Madigan-Hyland
(NYS Thruway)
1963 Post-hoc accident review
of “inattention” crashes
Higher crash rates in freeway sections with BBs than without; in
both medium and heavy traffic volumes
Blanche
(NJ Garden State Pky)
Undated Post-hoc accident review Accidents related to volume only
Faustman
(CA Route 40)
1961 Post-hoc accident review Crash rate was 41% higher for road sections with BBs than without
Weiner 1973 Statistical reanalysis of
Faustman data
BBs, traffic volume associated with significantly higher crash rates.
Ady 1967 Before-after accident study at
3 CEVMS locations
No crash rate changes at 2 locations; significant adverse changes at
location of sign at demanding location (curve, bridge)
Boston Tele-Spot
Decision
1976 Before-after accident study at
location of 1 CEBMS
10% difference in crash rates where sign visible than not
Johnstone & Cole 1976 Laboratory Visual distractors (simulated BBs) degraded tracking performance
and peripheral detection
Holahan et al 1978 Laboratory Reaction time to simulated STOP signs significantly slowed by
number, proximity, and color of visual distractors.
Holahan et al 1978 Post-hoc accident review At-fault, crashes higher at STOP-sign controlled intersections with
higher numbers, sizes, of distractors; not signalized intersections
Section 5:
Recent Research
Recent Research: ~1990 to Present
Smiley and Colleagues
VTTI – Lee and Colleagues
Tantala and Tantala
Others – reviews, research, theoretical
treatises
Farbry, et al
Bergeron
Wallace
Crundall
Are Longer Glance Durations of
Most Importance?
Recent studies have shown that a large percentage of
crashes occurred when a driver’s eyes were off the
road for 1.6 – 2 seconds (or longer) just prior to the
crash.
For years, researchers have analyzed means and
medians – Horrey and Wickens recently showed
that the tails of the distribution were more relevant.
Recent research seems to be demonstrating such
longer glances toward DBBs in the tails of the
distribution.
There is Much to be Learned from
Studies Not Related to DBBs
VTTI 100 car naturalistic driving study
North Carolina naturalistic driving study
Numerous studies of in-vehicle distractions
European, Australian studies of visual clutter
Studies of driver response to official CMS
Section 6:
Positive Guidance
The principles of “positive guidance” were
developed at FHWA by Gerry Alexander
and Hal Lunenfeld in the 1970s-80s.
These principles live on today in recent
European work, by researchers including
Theeuwes, Godthelp, Rasanen, Suummala,
and others.
In Europe, roads which are designed in
accordance with positive guidance principles
are generally known as “self explaining
roads.”
Section 7:
Aesthetics,
Visual Clutter
What About Aesthetics?
(This is the Highway Beautification Act)
Work in other countries has addressed the links
between aesthetics, visual clutter, driver
performance, and driver response to the roadside
environment.
Work by Pottier at INRETS (1990s) and by Edquist
at Monash University in Australia (ongoing)
suggests:
There is a link between judgment of aesthetics and visual
clutter
Driver performance in tasks such as road sign detection is
poorer, and requires more time, in environments that are
high in visual clutter.
We are not aware of similar work being done in the
US
Section 8:
Future Research
Different Research Methods
Laboratory studies, including simulator
Statistical analyses, including crash studies
In-vehicle, on-road, including “naturalistic”
Controlled field (real-world) studies
Laboratory and Simulator Studies
Pros:
Total control over visual scene and driving environment
Ability to vary key characteristics of signs
All participants experience identical situation
Control of variables supports clean data analysis
Cons:
Impossible to reproduce real-world scene complexity
Impossible to recreate brightness and contrast levels
Impossible to recreate sign legibility
Impossible to create high levels of driving task demands
Statistical/Crash Studies
Pros
On-road in actual location of interest
Large volumes of data
Before-after data collection; control sites possible
Cons
Changes in environment can impact data in unknown
ways
Crash onset location and place of rest are different
Most crashes not reported to police (1 in 5)
Most police crash investigations are cursory
Before-after data insufficient without proper baseline
Multiple, unknown contributors to many crashes
Involved drivers may not know, or wish to report, cause
In-Vehicle On-Road Studies
Pros
Enables control of key environmental variables
Enables precise measurement of dependent variables of
interest
Cons
Time consuming and expensive
Few participants reduces power
Difficult to establish true “naturalistic” setting in short
duration study
Cannot manipulate critical sign characteristics
Controlled Field Studies
Pros
Potential for total control of independent
variables
Potential for in-vehicle, driver-specific study,
crash data collection, and traffic performance
measurement
Can collect lots of targeted data in short time
Cons
Expensive and complex to conduct
Potential for novelty effect to confound data
An Hypothetical Controlled Field
Study
Identify DBBs and roadway of interest
Secure cooperation of sign owner and local authorities
Establish experimental protocol for sign display
characteristics – e.g. brightness, message design, duration,
sequencing
Deploy traffic measurement devices and cameras to capture
traffic parameters of interest
Capture and analyze: crashes, traffic movement, individual
driver responses to DBB under differing operational
conditions
Perform before-after and study-control site comparison
The Immediate Future
NCHRP Project 20-7
“Safety Impacts of Emerging Digital Display Technology
for Outdoor Advertising Signs
To begin shortly
FHWA Study
An update to FHWA’s 1980 and 2001 studies
To begin shortly
New TRB Subcommittee on Digital Signage
Reporting to all 4 committees in the safety of users track
Initial meeting Wednesday, 10:30AM – Noon, Marriott Truman
Room
Section 9:
New Technologies and
New Applications –
Beyond Digital
Billboards
Some Newer Technologies
Radio station identification
RFID identification and feedback
Dial your cell phone or text you a message
DBBs on moving vehicles
Vehicle aftermarket devices, e.g. LED wheels
Same truck – same location
Artistic Treatments – Some Examples
This sign sends a personalize message to
the approaching driver
Truck-Mounted, 2-Sided LED
“LED Wheels”
An Interactive Billboard in Belgium
1. The driver sends an SMS using a code from the
sign
2. The billboard sends a return message with a
question
3. The driver messages a response to the question
4. A correct answer causes the billboard to act like a
pinball machine – the driver is entered into a
Section 10:
Can’t We All Just Get Along?
Can’t We All Just Get Along?
Dealing with new technology
Dealing with new applications
Are there criteria that both industry and
government can live with?
Do we need stricter regulations or
enforcement, or might voluntary standards
suffice?
New Technologies
Highly realistic images on moving trucks
Video billboards on moving vehicles
Elevating truck-mounted LED billboards
Billboards that post personalized messages,
dial driver’s cell phone, send text messages
On-premise signs of great size, brightness
Personalized, vehicle based LED messaging
New Applications
Agreements for revenue generation
Road privatization
Toll facilities
Airports, rail stations, transit hubs
Potential EBBs at Toll Bridges
Potential EBBs at Airports
Potential EBBs at Tunnels
What About Self-Regulation?
OAAA has a “code of practice” for DBBs
Change interval 8 seconds
Reduce brightness at night
This is guidance, not a requirement
No enforcement capability
Necessary, but not sufficient
Is there an opportunity to add teeth?
Help for Local Governments
Needed
They ask:
How do standards for highway applications get
applied to the local level on city streets and in
residential neighborhoods – the driving task is
different; lower speeds, pedestrians, traffic
signals, uncontrolled access
What About On-Premise Signs
On-premise signs have traditionally been
given total freedom of design and operation
But DBBs are increasingly used on-premise
If we confirm that characteristics of DBBs do
cause dangerous levels of distraction, can we
continue to ignore on-premise signs?
Not your father’s on-premise sign:
LED - 165’ post; 90x65 ft. face
What Controls Might Work?
Site specific brightness control
Based on ambient light and driving task
Prevent multiple signs within visual range
Reduce potential for message sequencing
Site specific message change interval
Based on sight distance
Prohibit at locations of high task demands, or
high accident locations
The “Do-Good” Side of DBBs
Industry touts the ability of DBBs to aid law
enforcement and traffic control
Amber Alert
Homeland Security
Traffic rerouting after Minneapolis bridge collapse
Even official CMSs can cause trouble
Messages, and display methods, must follow proven
human factors principles, and must act in
concordance with official signs
What does the future
hold?
These days are gone forever
The future may look like this
We’re trying to prevent it from
looking like this
Thanks so much for
your interest, and for
your participation!
See you at the reception.