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.