VDOT

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VDOTs Work Zone Research and Practices

• Ben Cottrell
• Virginia DOT Research Council

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ASSESSMENT OF ADVANCED WARNING SIGNS FORFLAGGING
OPERATIONS

• Steve JonesBen Cottrell

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Introduction

• In 1983, MUTCD was revised to specify use of
  STOP/SLOW paddle as primary hand-signaling
  device.
• Paddle has been the standard since 1987.

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Background

• ATSSA asked FHWA to adopt proposed sign.
• In 1987, the two signs were included in ongoing
  FHWA human factors study using a driver
  simulator.
• Study concluded that proposed sign was not
  understood by drivers, and request was denied.

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Background (cont.)

• Paddle gained acceptance, and its use increased
  in work zone traffic control.
• Existing sign is not an accurate representation
  of traffic situation encountered by drivers.

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Purpose

• To evaluate ability of current and proposed sign
  to convey its intended message.
• To satisfy FHWA requirement of a human factors
  study on understanding and acceptance of proposed
  sign.

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Methodology

• Literature review
• Development of survey questionnaire
• Identification of participants
• Mailing of survey
• Analysis of survey results
• Development of conclusions

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Identification of Participants Mailing of Survey

• Sample groups chosen (open ended)
• Younger drivers in drivers education classes
• Older (gt 50) drivers at local senior center
• Survey mailed (multiple choice)
• Addresses randomly selected from Internet phone
  books
• 4,500 questionnaires mailed out

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Survey Statistics

• 3,600 delivered
• 1,383 replies including 20 via web site
• 759 existing sign
• 624 proposed sign
• 38 return rate

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Response Codes

• Correct implies clear understanding of intended
  sign meaning
• Substantially correct implies substantive
  understanding of intended sign meaning
• Incorrect implies total lack of understanding
  of intended sign meaning

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Survey Question 1 Have you ever seen this sign
in Virginia?
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Survey Question 2What do you think the sign
means?
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.
Survey Question 3 Where would you expect to see
this sign?
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Survey Question 4 What would you do if you saw
the sign while driving?

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Study Limitations

• Survey approach
• Survey Language
• - flagger versus traffic control person
• - influence of stop sign symbol
• - similarity in choices
• - sign meaning and driver behavior
• Single sign versus sign series

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Conclusions

• The proposed sign accurately symbolizes what
  motorists will see.
• The correct meaning of the existing sign was
  clearer to more respondents than the proposed
  sign.
• Designation of flagger as the only correct
  response was biased in favor of the existing
  sign. Stop ahead as an incorrect response was
  considered debatable.

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Conclusions (cont.)

• More respondents associated the desired driving
  behavior with the proposed sign than the existing
  sign.
• Asking what drivers would do when they see a
  sign is a better measure than asking what the
  sign means.
• The proposed sign performs as good as if not
  better than the existing sign.

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Recommendations

• The Traffic Engineering Division should seek FHWA
  approval to modify the Virginia Work Area
  Protection Manual to allow the use of the
  proposed sign.
• VDOT, in cooperation with other state DOTs and
  national groups, should request that the FHWA
  modify the MUTCD to allow the use of the proposed
  sign.
• STATUS Under Review by FHWA

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For more information

• Research Brief
• http//virginiadot.org/VTRC/briefs/00-r8rb/nigh
  t_work_zone_flash.htm
• Final Report http//virginiadot.org/VTRC/main/onl
  ine_reports/pdf/00-r8.pdf

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IMPROVING NIGHT WORK ZONE TRAFFIC CONTROL

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Why Night Work?
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Worker Safety
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Motorists Safety
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• The objective to examine traffic control for
  night work zones from the perspective of both
  worker and motorist.
• Approach investigate practices of other state
  DOTs, identify the problems associated with
  traffic control for night work zones, and
  potential strategies to resolve them.

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METHODS

• Literature Review
• Survey of State DOTs
• Survey of VDOT Residencies
• Review of Night Work Zones
• Motorists Survey
• Inventory of Strategies for Improvement

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Traffic Control Problems

• State DOTs
• Poor visibility
• Impaired drivers
• Higher speeds and lower volume
• Insufficient lighting

• VDOT Residencies
• Poor visibility
• Higher average speed
• Motorists inattention
• Inadequate lighting

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Solutions

• State DOTs
• Improve visibility of workers
• Use drums in taper
• Detail lighting plan
• Use police
• Maintain devices

• VDOT Residencies
• Use police
• Specify lighting requirements
• Use drums
• Use heavier cones

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CONCLUSIONS

• Reduced visibility, driver impairment or
  inattention, inadequate lighting, and lack of
  maintenance of traffic control devices are common
  problems.

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CONCLUSIONS

• Traffic control for night work zones, in general,
  is adequate. Common problem areas properly
  establishing work zones, maintaining the traffic
  control devices, and proper aiming and alignment
  of lighting to avoid glare.

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CONCLUSIONS

• Despite the perception that night work zones are
  less safe, evidence for this was not available.
  Based on a limited amount of data, there was no
  evidence of the perceived higher speeds at night.

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RECOMMENDATIONS

• Improving Visibility of Traffic Control Devices
• Worker and Work Vehicle Visibility
• Managing Traffic

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Improving Visibility of Traffic Control Devices

• Drums should be used in the transition area for
  lane closures.
• Consider requiring the contractor to have
  full-time traffic control staff. This staff and
  VDOT staff should ensure that the traffic control
  complies with the VWAPM, work lights are not
  creating glare and work vehicle lights are not a
  distraction.

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Improving Visibility of Traffic Control Devices

• Under conditions of limited sight distance, the
  transition area should be shifted upstream to
  improve the visibility of the taper. Similarly,
  when a lane closure merge point is near an entry
  ramp, the transition area should be shifted
  upstream to separate the two merge points.

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Worker and Work Vehicle Visibility

• All workers should wear hard hats that have
  retroreflective material that is visible from all
  sides. Ways to make retroreflective clothing
  visible through the full range of body motions
  should be considered.
• The NY DOT guidelines for use of work vehicle
  flashing and warning lights should be used.

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Managing Traffic

• PCMS messages should be appropriate for the road
  conditions present. A PCMS should be considered
  for end-of-queue warnings in the early hours when
  traffic volumes may result in queues and as
  special attention getters later at night.

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Managing Traffic

• When appropriate, the message TROOPER ON SITE,
  SPEED LIMIT ENFORCED should be used. The use of
  radar controlled PCMS should be considered as a
  countermeasure for speeding.
• The police vehicle should be positioned to
  maximize its visibility.

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IMPLEMENTATION PLAN

• Recommendations should be presented to the Work
  Zone Safety roundtable for review, revisions, and
  implementation.
• Employee Safety and Health Division should have
  lead responsibility in the areas of worker safety
  clothing such as hard hats.

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For more information

• Research Brief
• http//virginiadot.org/VTRC/briefs/00-r8rb/night_
  work_zone_flash.htm
•  
• Final Report http//virginiadot.org/VTRC/main/on
  line_reports/pdf/00-r8.pdf  

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VDOT Work Area Protection Manual and Practices
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Focus

• Highlight some areas where VDOT exceeds MUTCD.
• Traffic control and safety.
• Tools, training and public awareness.

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Cones and Signs

• standard size cone is 36 in.
• warning signs
• 48 in. standard size
• Fluorescent orange prismatic sheeting
• One size only minimize errors in size and
  simplifies inventory.

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Pavement Markings

• Objective to have pavement markings as good as
  or better than the original markings.
• Use a lot temporary tape.
• Raised pavement markers used in transition area.

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Lane Closures

• Extensive use of Truck Mounted Attenuators
• - TMAs shall be used on multilane highways with
  speed limit gt45 mph
• - VDOT has gt500 TMAs contractors have 500-800
  TMAs.
• Use two additional signs not in MUTCD Lane ends
  and Keep Left/Right.

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Portable Changeable Message Signs

• Extensive use of PCMSs for lane closures and lane
  shifts especially when queues are expected.
• Experimenting with 12 small PCMSs mounted on pick
  up and dump trucks for pavement marking and
  environmental operations.

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State Police in Work Zones

• Used in just about any interstate work zones
  especially in urbanized areas.
• Used on some primary and major secondary routes
  with high speeds.
• Police actively pursue speeders.

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Work Zone Safety Tools

• Work Zone Safety Pocket Guide
• Work Zone Safety Checklist
• Two page carbonless four copy form or electronic
  copy
• Completed by district safety officers during
  reviews and weekly by inspectors
• District Safety Officers have video recording
  system tied to DMI in vehicles

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Training

• Flagger Certification
• Now self administered program on videotape
• By late summer PC based testing at local DMV
  with photo id card
• Work Zone Training with VRTBA
• 1 day course 6-8/yr
• 300-400 Contractor and VDOT staff /yr

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Public Awareness Campaign

• VDOT Internet site
• http//virginiadot.org/comtravel/eoc/eoc-main.asp
  .
• Special Internet site for major projects.
• Regular daily feature in local newspapers and
  radio stations identifying work zones.

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QUESTIONS?