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
  • Flexible barrier separating traffic lanes and work area
  • Channelizing devices for delineation
  • Concrete barriers to separate work area
  • Passing traffic in close proximity to the on-foot worker with minimal protection from flexible barrier
  • Sample Road Projects and Potential Hazards
  • Vehicles parked within work area
  • Flashing arrow board is not operating

Advanced Warning Area

  • Advanced Warning Area
  • Transition Area
  • Activity Area
    • Work space
    • Traffic space
    • Buffer space
  • Termination Area
  • Components of Temporary Traffic Control Zones
  • (Source: MUTCD 2003)

Worker Safety Considerations in Work Zone Traffic Control

  • Modifying traffic control strategies to influence drivers’ perception of risk
  • 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

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

Key elements that SHOULD be considered to improve worker safety:

  • 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 Considerations
  • Worker safety apparel

All workers should be trained on:

  • 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 Consideration - TRAINING

Workers near motor vehicle traffic should wear bright, visible clothing

  • Workers near motor vehicle traffic should wear bright, visible clothing
  • Relevant OSHA Regulation
  • Worker Safety Consideration-
  • WORKER SAFETY APPAREL

Barriers shall be placed along the work zone depending on:

  • 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
  • Worker Safety Consideration - TEMPORARY TRAFFIC BARRIERS
  • Concrete Barriers

Speed of passing motorists may be influenced by:

  • Speed of passing motorists may be influenced by:
    • Regulatory speed zoning
    • Funneling
    • Use of law enforcement
    • Lane reduction
    • Presence of flaggers
  • Worker Safety Consideration –
  • SPEED REDUCTION MEASURES

Plan internal work space and activities

  • 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 THE ACTIVITY AREA

Hazard assessment should be conducted based on:

  • 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)
  • Worker Safety Consideration –
  • PLANNING FOR WORKER SAFETY

Shadow Vehicle with Impact Attenuator

  • 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
  • Optional Worker Safety Elements
  • Rumble strips

Common for mobile and constantly moving operations

  • Common for mobile and constantly moving operations
  • Optional Worker Safety Elements -
  • SHADOW VEHICLE
  • Shadow vehicle with rear mounted crash attenuator
  • Should be equipped with:
    • Appropriate lights
    • Warning signs
    • Rear-mounted impact attenuator
  • Crash with a truck without an impact attenuator
  • Crash with a truck with a truck mounted impact attenuator
  • Truck Mounted Attenuator

Reduce worker vulnerability to risk of injury

  • 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
  • Optional Worker Safety Elements -
  • ROAD CLOSURE
  • Freeway closure for one direction of traffic

Police units may be stationed in a work zone to:

  • 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 -
  • USE OF POLICE ENFORCEMENT

Additional lighting should be provided at work zones that operate during the night

  • Additional lighting should be provided at work zones that operate during the night
  • Optional Worker Safety Elements -
  • LIGHTING
  • 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
  • Channelizing Devices
  • KEY
  • Sign Location
  • Note: Distance in feet, drawing not to scale
  • W21
  • -
  • 4
  • W20
  • -
  • 5
  • R2
  • -
  • 5b
  • W4
  • -
  • 2R
  • R2
  • -
  • 1
  • G20
  • -
  • 2
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • XX
  • AHEAD
  • XX
  • SPEED
  • LIMIT
  • XX
  • SPEED
  • LIMIT
  • SPEED
  • LIMIT
  • 1400’
  • 700’
  • 600’
  • 700’
  • 700’
  • 700’
  • 700’
  • Flashing
  • Arrow Panel
  • Median
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • XX
  • AHEAD
  • XX
  • SPEED
  • LIMIT
  • XX
  • SPEED
  • LIMIT
  • SPEED
  • LIMIT

Work Zone Traffic Control

  • MUTCD provides minimum requirements
  • Various demanding situations may warrant enhanced safety precautions, such as:
  • 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

  • Passing motorist intruding into the work space
  • Hazards related to flagging
  • Nighttime hazards
  • Common Hazards

Hazards of Work Zone Traffic Control

  • 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
  • Causal Factors

General Preventive Measures

  • Traffic Control
    • Use additional warning devices
    • Maintain signs properly
    • Use Proper lane markings
  • Flaggers
    • Use a flashing slow/stop paddle
  • On-foot workers
    • Use portable radio communication equipment
  • Law enforcement
    • Use officers and radar surveillance for traffic speed control

Hazard: Passing Motorists Intruding Into Work Space

  • Hazard mitigation measures
    • Use of proper speed reduction methods
    • Proper design of the wok zone
    • Provide effective traffic control measures
  • Causes of Hazards
    • High approach speed
    • Improper geometry of the lane shift
    • Improper traffic control
    • Inadequate information system
  • No physical separation between work space and traffic lane

Hazard: Passing Motorists Intruding Into Work Space

  • Exceed minimum standards/guidelines for traffic control
    • Rumble strips
    • Lane drop arrows
    • Lighted raised pavement markers
    • Radar triggered speed display
    • Safety warning system
    • Combinations of the above
  • Preventive Measures:
  • Truck may intrude into the work zone
  • Sample Work Zone Traffic Control Layout With Additional Safety Features
  • For a Single Lane Closure
  • Truck Mounted
  • Attenuator
  • W21
  • -
  • 4
  • W20
  • -
  • 5
  • R2
  • -
  • 5b
  • W4
  • -
  • 2R
  • R2
  • -
  • 1
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • REDUCED
  • SPEED
  • XX
  • AHEAD
  • XX
  • AHEAD
  • XX
  • SPEED
  • LIMIT
  • XX
  • SPEED
  • LIMIT
  • SPEED
  • LIMIT
  • D
  • D
  • G20
  • -
  • 2
  • D
  • G20
  • -
  • 2
  • D
  • D
  • D
  • D
  • L
  • XX
  • Your
  • Speed is
  • XX
  • Your
  • Speed is
  • White Pavement
  • Markings Symbol
  • Retroreflective Raised
  • Pavement Markers
  • Increase Buffer
  • Area
  • Radar Triggered
  • Speed Display
  • Temporary Rumble
  • Strips
  • Flashing
  • Arrow Panel

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 CB-equipped 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 struck by a motorist
  • 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
  • Nonstandard paddle height

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

Flaggers must avoid

  • 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
  • Injury Prevention Techniques for Flaggers

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
  • End of Module 1


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