Variable Speed Limits (VSL) in Work Zones Webinar June 19, 2019 - - PowerPoint PPT Presentation

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Variable Speed Limits (VSL) in Work Zones Webinar June 19, 2019 - - PowerPoint PPT Presentation

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Variable Speed Limits (VSL) in Work Zones Webinar June 19, 2019 This webinar will be recorded. Agenda VSL in Work Zones: DOT Experiences Ohio DOT Emily Willis, Maintenance of Traffic Engineer Utah DOT Josh Van Jura, State

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Variable Speed Limits (VSL) in Work Zones

Webinar June 19, 2019

This webinar will be recorded.

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Agenda

  • VSL in Work Zones: DOT Experiences

– Ohio DOT – Emily Willis, Maintenance of Traffic Engineer – Utah DOT – Josh Van Jura, State Construction Engineer

  • Other NWP Related Experiences
  • Questions and Answers
  • Closing
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VARIABLE SPEED LIMITS IN WORK ZONES

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OHIO DOT WORK ZONE SPEED ZONES

Emily Willis

Variable Speed Limits in Work Zones

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PREVIOUS WORK ZONE SPEED ZONE POLICIES

Variable Speed Limits in Work Zones

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HISTORY OF PREVIOUS WZSZ POLICY

PRIOR TO 2011

  • Limited to long-term construction projects
  • Compliance was difficult to achieve
  • 24/7 speed limit reductions

Variable Speed Limits in Work Zones

Located on Multi-Lane Highway (≥ 55 mph) Work Zone Condition ≥ 1/2 Mile Expected Work Duration of ≥ 30 Days Static 10 MPH Reduction for Duration of the Project

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HISTORY OF PREVIOUS WZSZ POLICY

IN 2011 (2011 to 2015)

  • Changed expected duration; Removed minimum length
  • Opened to all construction and maintenance that meets
  • Compliance still difficult to achieve

Variable Speed Limits in Work Zones

Criteria

Multi-lane highway (≥ 55 mph) Expected duration

  • f ≥ 3

hrs.

Guidelines Table

Look up applicable conditions and factors to see if a WZSZ may be warranted .

Adapted from NCHRP Report 3-41(2).

Recommend Speed Limit

If indicated, calculate and recommen ded a speed limit.

Using a standard statewide WZSZ Evaluation

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DEVELOPING NEW WORK ZONE SPEED ZONE POLICY

Variable Speed Limits in Work Zones

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OHIO LAW – 4511.98

Variable Speed Limits in Work Zones

“The director

  • f

transportation may establish speed limits within construction zones that vary based on the type of work being conducted, the time of day, or any other criteria the director may consider appropriate.”

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DEVELOPMENT OF NEW WZSZ POLICY

  • Research conducted by Texas A&M

Transportation Institute, Cleveland State University, Ohio University

  • Determine effectiveness of ODOT

processes for establishing work zone speed zones and variable work zone speed zones

Variable Speed Limits in Work Zones

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DEVELOPMENT OF NEW WZSZ POLICY

  • Simply putting up speed limit signs does

not slow drivers down

  • Drivers only reduce their speeds through

the work zone when they perceive a need to do so, based on conditions in the work zone or the perception of enforcement activities

Variable Speed Limits in Work Zones

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DEVELOPMENT OF NEW WZSZ POLICY

  • Worked with Ohio Contractor’s Association

and Ohio State Highway Patrol to develop new process and new signage options

  • Focus on worker presence as “the need”

for drivers to slow down

Variable Speed Limits in Work Zones

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CURRENT WORK ZONE SPEED ZONE POLICY

Variable Speed Limits in Work Zones

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WORK ZONE SPEED LIMIT VALUES

  • All Work Zone Speed Zones (WZSZ’s) are

variable and will frequently fluctuate between:

  • Two approved reduced speed limits or
  • An approved reduced speed limit and the original posted

speed limit

Variable Speed Limits in Work Zones

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CONDITIONS WARRANTING WZ SPEED ZONE

Variable Speed Limits in Work Zones

Multi- Lane Highway (≥ 55 mph)

Reduced Existing Functionality

  • f Lanes or

Shoulders Work Zone Condition of ≥ ½ Mile Expected Duration of ≥ 3 Hrs Follow Table for Warranted WZ Speed Limits for Qualifying Conditions and Factors

  • Does not apply to Moving/Mobile Operations
  • When criteria no longer are met, the speed limit returns to

the original preconstruction speed limit.

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WORK ZONE SPEED LIMIT DEPENDENCIES

  • Original Posted Speed Limit (Preconstruction)
  • Type of temporary traffic control used
  • WITH Positive Protection: Portable Barrier or other rigid

barrier

  • WITHOUT Positive Protection: Drums, cones, shadow vehicle,

etc.

  • Whether or not workers are present

Variable Speed Limits in Work Zones

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WORK ZONE SPEED LIMIT VALUES

  • Warranted Speed Limit Values (Table

1297-7)

Variable Speed Limits in Work Zones

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TWO SIGNING STRATEGIES FOR IMPLEMENTATION

Primary strategy: Digital Speed Limit (DSL) Sign Assemblies

Variable Speed Limits in Work Zones

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TWO SIGNING STRATEGIES FOR IMPLEMENTATION

Secondary strategy: Traditional Temporary Flatsheet Speed Limit signs

Variable Speed Limits in Work Zones

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APPROVED LIST FOR DSL

Ver-Mac American Signal Solar Tech Work Area Protection

Variable Speed Limits in Work Zones

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CONSIDERATIONS DURING DESIGN

Variable Speed Limits in Work Zones

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DESIGN SPEEDS

  • Initial approaches to the work zone based on the
  • riginal preconstruction speed limit
  • Remaining elements within need to accommodate

whichever speed limit is in effect at that time

  • Adjust each time speeds change
  • Use the more conservative design speed for each

element

  • Higher speed for tapers, buffers, clear zones, etc.
  • Lower speed for device spacing, etc.

Variable Speed Limits in Work Zones

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WZSZ USING DIGITAL SPEED LIMIT (DSL) SIGN ASSEMBLY

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WZSZ USING TEMPORARY FLATSHEET SPEED LIMIT SIGNS

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CONSIDERATIONS DURING CONSTRUCTION

Variable Speed Limits in Work Zones

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COMMUNICATION WITH LAW ENFORCEMENT

  • Notify law enforcement agency
  • Prior to initial WZSZ implementation
  • Daily before enforcement begins
  • Prior to removal of WZSZ

Variable Speed Limits in Work Zones

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WORK ZONE SPEED ZONE TRACKING REPORT

  • Contractor to track/log all speed limit

changes as they occur; Submit weekly

Variable Speed Limits in Work Zones

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?

QUESTIONS

Variable Speed Limits in Work Zones

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Use of Portable and Dynamic Variable Speed Limits in Construction Zones

Josh Van Jura

Utah Department of Transportation

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➢Centerline Miles by Type

➢ 935 miles of Interstate ➢ 2,945 miles of Level 1 (AADT>1,000) ➢ 1,985 miles of Level 2 (AADT<1,000) ➢ 5,865 miles total

➢Speed Limits

➢ 13% @ 80 mph ➢ 35% @ 70mph or higher ➢ 60% @ 60mph or higher ➢ 82% @ 50mph or higher

Overview of UDOT

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Project Goal Goal: Improve safety within construction work zones through significant reduction in traveler speed within the boundary of Active Work Space.

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Posted vs. Operating Speed

Kloeden et al., 1 9 9 7 , 2 2 West and Dunn 1971 Delta = ~2.5%

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Reduction of Operating Speed

  • Portable, Intelligent and Dynamic
  • Regulatory
  • Multiple Devices (PVSL, Detectors, PVMS)
  • Integrated as one system
  • Dynamically posting speed limits
  • Traveler information messages
  • Operated by Contractor and UDOT Field Crews (No TOC)
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PVSL System: How we are getting there

  • FHWA AID Grant
  • Awarded December 2014
  • System Planning & Design
  • NTP June 2015
  • and .
  • Turn-key Solution Provider
  • NTP May 2016
  • and
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System Components 1

  • Portable Variable Speed Limit Signs (PVSL)
  • White LEDs on black background (Regulatory)
  • Speed Detection Trailers
  • K-Band Doppler Speed Radar
  • Portable variable message sign (PVMS)
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System Components 2

  • Portable Operator Control Device
  • Laptop / Tablet / Cell Phone
  • Cell Service Req’d
  • Communications
  • Internet via cell phone network
  • Power
  • Solar system with 7-day batteries
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Operational Scenario

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Legend: Average Speed = Calculated Average Speed based on rolling 5 minutes of speed measurements in active work space . VSL SL = Speed limit posted on VSL sign. TEO High = Maximum speed allowed by TEO, typically Original Posted Speed or Original Posted Speed – 10 mph . TEO Low = The lowest speed limit allowed by TEO. Frequency of Speed Limit Change = Minimum of 15 minutes between speed limit changes Bad or No Data Received => VSL SL = Last known VSL SL VSL SL = Average Speed (rounded down to nearest 5 mph) – 5 mph Average Speed > (TEO High + 10 mph) VSL SL = (TEO High – 5 mph) Start with VSL SL = TEO Low Calculate Average Speed YES NO Average Speed > TEO High Average Speed < (TEO Low + 10 mph) YES NO YES VSL SL = TEO High VSL SL = TEO Low NO Average Speed < 35 mph VSL SL = TEO Low (Queue within active work space) YES NO

VSL Subsystem Algorithm

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PVSL Trailers

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Software (Desktop)

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Software (Mobile)

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System Alerts

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10 20 30 40 50 60 70 80 7:00 AM 7:30 AM 8:00 AM 8:30 AM 9:00 AM 9:30 AM 10:00 AM 10:30 AM 11:00 AM 11:30 AM 12:00 PM 12:30 PM 1:00 PM 1:30 PM 2:00 PM 2:30 PM 3:00 PM 3:30 PM 4:00 PM 4:30 PM 5:00 PM 5:30 PM 6:00 PM 6:30 PM 7:00 PM 7:30 PM 8:00 PM Speed (mph) Time of Day

Honeyville Speed Data Summary: June 21, 2017

5 Minute Rolling Average Speed PVSL #1 PVSL #2

Honeyville Speed Data Summary: June 21, 2017

Direction of Travel

PVSL #2 PVSL #1 AWS Detector

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PVSL #1 PVSL #2 AWS Detector PVSL #1 AWS Detector PVSL #2

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Honeyville Speed Data -6.21.2017

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I-80 Speed Data – 7.13.2017

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Speed Compliance

Project Speeds < 10mph Over Posted Speed 10mph < Speeds < 15mph Speeds >=15mph Over Posted Speed Baseline PVSL Baseline PVSL Baseline PVSL Y1P1, Tremonton 23% 37% 10% 15% 67% 48% Y2P1, Meadows 88% 58% 9% 29% 3% 13% Y2P2, Honeyville N/A 60% N/A 29% N/A 10% Y2P3, I-80 43% 81% 42% 14% 15% 6%

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Other Important Factors

  • Public Information
  • Communicate impact and duration
  • 1.5 miles = 52 seconds
  • Real time messages
  • Challenges
  • Comfort w/ automation
  • Supporting Legislation
  • Just because you can doesn’t mean you should
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Contact Information

Joshua Van Jura UDOT Project Manager jvanjura@utah.gov (801) 231-8452

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Questions/Other Experiences

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Closing

  • Contacts for more information

– Emily Willis

  • Emily.Willis@dot.ohio.gov

– Josh Van Jura

  • jvanjura@utah.gov

– Brandon Beise, North Dakota DOT

  • bbeise@nd.gov

www.nwpassage.info