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Module 1: Work Zone Traffic Control

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Module 1: Work Zone Traffic
Control
Overview of Module 1
• Underlying principles of work zone traffic
control
• Manual of Uniform Traffic Control Device
(MUTCD)
– Features of work zone traffic control
• Hazards associated with work zone traffic
control
• Injury prevention techniques
• Summary
Work Zone Traffic Control
• Influences drivers’ perception of risk
– Provides information on potential hazards
– Minimizes aggressive behavior
– Assists in navigation
• Engineering concerns for work zones
– Primary focus: Safe and efficient movement
of vehicles through work zone
– Relatively less emphasis on safety of
construction workers
Type of Barrier
• Rigid Barriers
– Provide separation between
• Opposing traffic lanes
• Traffic lanes and work area
– Cause damage to motorists if struck
Concrete barrier
separating
opposing traffic
Concrete barrier
separating traffic
lanes and work area
Type of Barrier
• Flexible barriers (channelizing devices)
– Provide nominal protection for workers
– Flexible and deformable, do not cause damage if struck
Concrete barriers to
separate work area
Flexible barrier
separating traffic
lanes and work area
Channelizing devices
for delineation
Sample Road Projects and
Potential Hazards
Vehicles parked within work
area
Passing traffic in close proximity
to the on-foot worker with minimal
protection from flexible barrier
Flashing arrow board is not
operating
Components of Temporary Traffic
Control Zones
(Source: MUTCD 2003)
• Advanced Warning Area
• Transition Area
• Activity Area
– Work space
– Traffic space
– Buffer space
• Termination Area
Worker Safety Considerations in
Work Zone Traffic Control
• Modifying traffic control strategies to influence
drivers’ perception of risk
– Leads to more careful and slower driving
– Improves safety for the workers
• Examples:
– Providing active warning devices
• Illuminated arrow boards
• Reliable advisory speed limit
• Active message with flashers
– Narrower lane widths
– Longer and/or wider buffer zones
– Rigid barriers to separate workers from travel lanes
�Positive Guidance’ Approach
• May be used to improve safety in work zones
• Combines highway/traffic engineering features
with what rational drivers expect
• Considers:
– Various age groups of drivers
– Complexity of work zone information handling
– Limited capability of humans for detecting, processing,
and remembering information
MUTCD – Manual on
Uniform Traffic Control Devices
• Recognized as the national standard
• Enforcement agencies often adopt it by
reference
• Provides guidance, options and
supporting materials
– To assist professionals in making
decisions regarding the use of traffic
control on streets and highways
MUTCD- Part 6:
Temporary Traffic Control
• Primary function of
temporary traffic control:
– “To provide for reasonably safe and
efficient movement of road users
through or around temporary traffic
control zones while reasonably
protecting workers, responders to
traffic incidents, and equipment”
Temporary Traffic Control
• Work zones present constantly
changing conditions
– Unexpected by the road user
– Creates higher degree of vulnerability for
workers
Temporary Traffic Control
Devices
• Temporary traffic control
(TTC) devices include
–
–
–
–
Signs
Signals
Markings
Other devices
• Used to regulate, warn, or
guide road users
Types of TTC Applications
• Each TTC zone is different
• Many variables affect the needs of each
zone:
–
–
–
–
Location of work
Duration of work
Highway type
Geometrics
• Vertical and horizontal alignment, intersections,
interchanges, etc.
– Road user volumes
• Road vehicle mix (buses, trucks, and cars) and
road user speeds
Work Duration
• Major factor in determining the number and types of
devices used in TTC zones
• As per the MUTCD, five categories of work duration are
defined:
– Long-term stationary is work that occupies a location
more than 3 days
– Intermediate-term stationary is work that occupies a
location more than one daylight period up to 3 days, or
nighttime work lasting more than 1 hour
– Short-term stationary is daytime work that occupies a
location for more than 1 hour within a single daylight
period
– Short duration is work that occupies a location up to 1
hour
– Mobile is work that moves intermittently or continuously.
Long Term Stationary Work
(more than 3 days)
• Typically utilize a full range of TTC
procedures and devices
– Project duration far exceeds installation
time of TTC
– TTC elements may include:
• Larger channelizing devices, temporary
roadways, and temporary traffic barriers
• Retroreflective and/or illuminated devices
Intermediate-Term Stationary Work
(up to 3 days, or nighttime work lasting more than 1 hour)
• May not be practical to use the same
procedures or devices for long-term
stationary TTC zones
– Such as altered pavement markings, temporary
traffic barriers, and temporary roadways
• Increased time to place and remove these
devices could significantly lengthen the
project, thus increasing exposure time
Short-Term Stationary Work
(more than 1 hour within a single daylight period)
• Most maintenance and utility operations are
short-term stationary work
– Include activities that might involve different
treatments
– Devices having greater mobility might be
necessary
• Signs mounted on trucks
– Appropriately colored or marked vehicles with
rotating/strobe lights may be used in place of
signs and channelizing devices
• May be augmented with signs or arrow panels
Short Duration Work
(up to 1 hour)
• Often takes longer to set up and remove the TTC
zone than to perform the work
– Workers face hazards in setting up and taking down
the TTC zone
– Delays affecting road users are significantly
increased when additional devices are installed and
removed
• Simplified control procedures may be warranted for
short-duration work
– Reduction in the number of devices
– Use of high-intensity rotating, flashing, oscillating, or
strobe lights on work vehicles
Mobile Work
• Often involve frequent short stops for activities
– Such as litter cleanup, pothole patching, or utility
operations, and are similar to short-duration operations
• TTC zones may includes:
– Warning signs, high-intensity rotating, flashing,
oscillating, or strobe lights on a vehicle, flags, and/or
channelizing devices
– Flaggers
– A shadow vehicle equipped with an arrow panel or a sign
following the work vehicle
– Appropriately colored and marked vehicles with signs,
flags, high-intensity rotating, flashing, oscillating, or
strobe lights, truck-mounted attenuators, and arrow
panels or portable changeable message signs may
follow a train of moving work vehicles
Worker Safety Considerations
• Key elements that SHOULD be
considered to improve worker
safety:
–
–
–
–
–
–
Training
Worker safety apparel
Temporary traffic barriers
Speed reduction measures
Planning of activity area
Planning for worker safety
Worker safety apparel
Worker Safety Consideration TRAINING
• All workers should be trained on:
– Working safely adjacent to vehicular traffic
– Work zone traffic control techniques
– Device Usage
• Safety devices
• Traffic control devices
– Placement of traffic control devices
• Relevant OSHA Regulation
– 29 CFR 1926.21, Safety Training and Education
Worker Safety ConsiderationWORKER SAFETY APPAREL
• Workers near motor vehicle traffic should wear
bright, visible clothing
• Relevant OSHA Regulation
– 29 CFR 1926.95, Criteria for Personal Protective
Equipment
Worker Safety Consideration TEMPORARY TRAFFIC BARRIERS
• Barriers shall be placed along the
work zone depending on:
– Lateral clearance of workers from
adjacent traffic
– Speed of traffic
– Duration and type of operations
– Time of day
– Volume of traffic
• Relevant OSHA Regulations
– 29 CFR 1926.200(g), Traffic Signs
– 29 CFR 1926.201, Signaling
– 29 CFR 1926.202, Barricades
Concrete Barriers
Worker Safety Consideration –
SPEED REDUCTION MEASURES
• Speed of passing motorists may
be influenced by:
–
–
–
–
–
Regulatory speed zoning
Funneling
Use of law enforcement
Lane reduction
Presence of flaggers
Worker Safety Consideration –
PLANNING THE ACTIVITY AREA
• Plan internal work space and activities
– Minimize the use of backing maneuvers of
construction vehicles
– Minimize interactions between on-foot workers,
equipment and trucks
• Minimize worker exposure to risk
– Develop internal traffic control plan and
operations
• Refer to “Module 2: Safe Operations and Internal
Traffic Control in the Work Space”
Worker Safety Consideration –
PLANNING FOR WORKER SAFETY
• Hazard assessment should be conducted based
on:
– Characteristics of work site
– Job classifications required in the work area
• Must comply with all relevant OSHA regulations
– Assess worker risk exposures for each job site and
job classification
• 29 CFR 1926.20, General Safety and Health
Provisions
• 29 CFR 1926.20 (b) (2)
Optional Worker Safety Elements
•
•
•
•
•
Shadow Vehicle with Impact Attenuator
Road Closure
Police enforcement
Additional Lighting
Special Devices
–
–
–
–
–
–
Rumble strips
Changeable message signs
Hazard identification beacons
Flags
Warning lights
Intrusion warning devices
Rumble strips
Optional Worker Safety Elements SHADOW VEHICLE
• Common for mobile and constantly moving
operations
• Should be equipped
with:
– Appropriate lights
– Warning signs
– Rear-mounted impact
attenuator
Shadow vehicle with rear
mounted crash attenuator
Truck Mounted Attenuator
Crash with a truck
with a truck mounted
impact attenuator
Crash with a
truck without an
impact attenuator
Optional Worker Safety Elements ROAD CLOSURE
• Reduce worker vulnerability
to risk of injury
• Provide more spacious
areas to conduct work
activities
• Eliminate threat of intruding
vehicles from passing traffic
• Aid in faster project
completion
Freeway closure for one
direction of traffic
Optional Worker Safety Elements USE OF POLICE ENFORCEMENT
• Police units may be
stationed in a work zone to:
– Heighten awareness of
passing motorists
– Improve safety through work
zone by enforcing speed limits
Optional Worker Safety Elements LIGHTING
• Additional lighting should
be provided at work
zones that operate
during the night
• Nighttime work requires
extra caution due to:
– Poor night time visibility
– Impairment of workers related
to fatigue
– Impairment of drivers
Nighttime work is
common in highway/street
construction projects
Sample Work Zone Traffic Control
Layout
• For a Single Lane Closure as per MUTCD
– Pre-construction speed limit is 70 mph
REDUCED
SPEED
XX
REDUCED
SPEED
SPEED
LIMIT
XX
W21-4
1400’
700’
Flashing
Arrow Panel
XX
AHEAD
R2-5b
W20-5
Median
SPEED
LIMIT
XX
AHEAD
R2-1
W4-2R
700’
KEY
Channelizing Devices
Sign Location
700’
700’
700’
G20-2
600’
Note: Distance in feet,
drawing not to scale
Work Zone Traffic Control
• MUTCD provides minimum requirements
• Various demanding situations may warrant
enhanced safety precautions, such as:
–
–
–
–
Nighttime work
Inclement weather conditions
Unusual roadway geometry and environment
Combinations of the above
• Going beyond existing standards/guidelines may
be necessary to ensure highest levels of traffic
and worker safety
Work Zone Traffic Control Hazards
and
Injury Prevention Techniques
Hazards of Work Zone Traffic
Control
Common Hazards
• Passing motorist intruding into the work space
• Hazards related to flagging
• Nighttime hazards
Hazards of Work Zone Traffic
Control
Causal Factors
• Conditions unexpected by the moving traffic
– Violation of driver expectancy
• Conditions unexpected by the workers
– Aggressive drivers
– Unplanned work zone/activity
• Injuries can occur due to
– Motorists’ mistakes
– Workers’ mistakes
– Deficiencies in the work zone environment
General Preventive Measures
• Traffic Control
• On-foot workers
– Use portable radio
– Use additional • Flaggers
– Use a flashing
communication
warning devices
slow/stop paddle equipment
– Maintain signs
properly
– Use Proper lane
markings
• Law enforcement
– Use officers and radar
surveillance for traffic speed
control
Hazard: Passing Motorists
Intruding Into Work Space
• Causes of Hazards
– High approach speed
– Improper geometry of the
lane shift
– Improper traffic control
– Inadequate information
system
• Hazard mitigation measures
No physical separation between
work space and traffic lane
– Use of proper speed reduction methods
– Proper design of the wok zone
– Provide effective traffic control measures
Hazard: Passing Motorists
Intruding Into Work Space
Preventive Measures:
• Exceed minimum standards/guidelines
for traffic control
–
–
–
–
–
–
Rumble strips
Lane drop arrows
Lighted raised pavement markers
Radar triggered speed display
Safety warning system
Truck may intrude into the
Combinations of the above
work zone
Sample Work Zone Traffic Control
Layout With Additional Safety
Features
• For a Single Lane Closure
Retroreflective Raised
Pavement Markers
Temporary Rumble White Pavement
Strips
Markings Symbol
Increase Buffer
Area
REDUCED
SPEED
XX
AHEAD
R2-5b
W20-5
D
D
KEY :
C h an n e lizin g D e vice s
Sig n Lo catio n
D
D istan ce B e tw e e n T raffic C o n tro l D e vice s
L
Le n g th o f Lo n g itu d in al B u ffe r Sp ace
XX
Radar Triggered
Speed Display
SPEED
LIMIT
XX
W21-4
Your
Speed is
D
Flashing
Arrow Panel
R2-1
W4-2R
D
D
G20-2
D
L
Truck Mounted
Attenuator
Innovative Technologies for
Hazard Control
•
•
•
•
•
Vertical safetycade
CB wizard alert system
Radar triggered speed display
White lane drop arrows
Lightguard lighted raised pavement
markers
• Removable orange strips
• Flashing slow/stop paddle
Vertical Safetycade
• Designed to replace standard channelizing
devices
• Benefits:
–
–
–
–
Better visibility
More positive guidance
Greater portability
Improved recoverability
• Collapsible frame
Vertical Safetycades
CB Wizard Alert System
• Trailer-mounted system
• Broadcasts a recorded
message to all CBequipped motorists
• Notify drivers of
downstream work zones
• Allows truck drivers to
lower their speeds in
advance of work zone
CB Wizard
Advanced
Warning Unit
CB Wizard Unit
Radar-Triggered Speed Display
• Back-lit dynamic speed
display
• Standard speed limit sign
• Strobe flash (optional)
– Strobe will flash when a vehicle
exceeds a certain speed
• Trailer mounted
Lane Drop Arrows
• Alert driver in
advance of lane
closure
• Encourage drivers to
reduce speed and
move to the open
lane
Lightguard Lighted Raised
Pavement Markers
• Provide greater visibility in work zones
• Can be:
– Flashing lights
– Racing lights
– Steady-burn lights
With Lightguard
Lighted Raised
Pavement Markers
Without Lightguard
Lighted Raised
Pavement Markers
Removable Orange Rumble Strips
• Alert motorists of a work
zone
• Benefits:
– Highly visible
– Repeating rumble sound
– Vibration of the steering
wheel
– Easy to install and
remove
– Reduce approach speed
Flashing Slow/Stop Paddle
• Consists of a standard
paddle with a strobe
light mounted on its
face
• Increases flagger
visibility to passing
motorists
Hazard: Flagging Operation
• 20 flaggers die each year from being Nonstandard
paddle
struck by a motorist
height
• Flagging can be hazardous as a result of:
–
–
–
–
High speed of passing traffic
Aggressive drivers in traffic stream
Insufficient stopping sight distance for motorists
Improper procedures used by flaggers
•
•
•
•
Not wearing personal protective equipment
Inattention
Use of nonstandard equipment
Improper flagging techniques
– Hazardous environmental conditions
• Fog, obstructions, wet pavements
Paddle
inclined
Injury Prevention
Techniques for Flaggers
• Wear high visibility clothing
– Appropriate for expected weather
(rain gear, warm coat, etc.)
• High visibility hard hat
• Use a standard SLOW/STOP
paddle or flag
– Flags are for emergency purposes
only
Injury Prevention
Techniques for Flaggers
• STAY ALERT, keep focused on
your work
• Stand alone on shoulder in clear
view, not in the open traffic lane
• Plan an escape route for
emergencies
• Stay in communication with the
other flaggers
• Treat motorists with respect
• Obtain proper training for flaggers,
including safety training
Injury Prevention
Techniques for Flaggers
• Flaggers must avoid
– Standing where the flagger can be hit
by a vehicle
– Standing in the shade, around a sharp
curve
– Standing in a group
– Standing near equipment
– Making unnecessary conversation
– Reading or day dreaming
– Listening to music or using ear phones
– Turning their back to approaching
traffic
Hazard: Nighttime Traffic Control
• Nighttime traffic control is more
challenging
– Poor visibility for drivers
– Poor visibility for workers
– Impaired or drowsy drivers
– Sleep deprived workers
Nighttime Traffic Control
Injury Prevention
• Use special precautions for
nighttime traffic control
–
–
–
–
Retro-reflective clothing
Flashing lights on body/clothing
Retro-reflective tape on equipment
Good work area lighting
Summary of the Module
• Work zone traffic creates serious hazards for
motorists and workers
• Provisions of MUTCD may not be sufficient for
preventing injuries/fatalities of on-foot workers
• Additional injury prevention techniques should
be implemented to prevent injuries to on-foot
workers
• Positively guiding traffic through the complex
work zone is the key to safety
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