Brownwood Portable Traffic Signals and AFADs Evaluation. Carl Johnson, P.E., TxDOT Brownwood District Melisa Finley, P.E., TTI

Transcription

1 Brownwood Portable Traffic Signals and AFADs Evaluation Carl Johnson, P.E., TxDOT Brownwood District Melisa Finley, P.E., TTI

2 Using Portable Traffic Signals (PTS) in Maintenance Operations: Brownwood District Operations

3 Trailer mounted LED signal heads Solar powered Remote control Compliant WZTC device TXMAS approved Proprietary What Are PTS?

4 How We Use PTS? Traffic actuated Vehicles detected Each signal red rest until vehicle detected Manually operated Pilot car operation Highly variable traffic patterns Create gaps in traffic through work zone

5 Why We Got PTS? Safety of employees Safety of motorists Extra personnel to be used on the job or another job

6 Primary Motivator - SAFETY VISIBILITY / RESPECT

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9 Ultimate safety for crew Remote control operation More recognized by public Pilot Vehicle

10 PTS Controller & Presets

11 Nothing trumps safety PTS are another tool Conclusions We all have a lot of work to do, signals can free up FTE s for other work How do you get them? GSA contract (ready to go) Minor equipment, capital purchase Talk to your Fleet Forward team

12 Now, the research

13 2009 MUTCD & 2011 Texas MUTCD Do not prohibit a pilot vehicle in conjunction with PTS Require a flagger on each approach when a pilot vehicle is used Section 6c.13 Paragraph 4: A flagger shall be stationed on the approach to the activity area to control vehicular traffic until the pilot vehicle is available.

14 FHWA Interpretation August 31, 2010 Pilot vehicle may be used with PTS provided a flagger is stationed on each approach To reassure motorists that they Have encountered a work zone Will eventually be able to proceed To alert work crew of violations

15 Field Study May 2013 Lane closures on two-lane, two-way roads To assess compliance with PTS and a pilot vehicle PTS with flaggers and a pilot vehicle

16 Site Road 2011 AADT (vpd) Sites Speed Limit (mph) Lane Closure Length (ft) See Work Activity? See Other PTS? 1 SH No No 2 FM Yes Yes 3 US Yes No 4 US Yes Yes

17 Signal Phasing and Queuing Data Site Avg. Stop Duration (min:sec) % Time Green Time Used 30 sec 60 sec 90 sec Avg. Veh. In Queue % Time Queue Didn t Clear Avg. Veh. Didn t Clear 1 4: : NA 3 3: : Total 4:

18 Violation Data Violation = Driver passed PTS when steady circular red indication displayed Treatment # of Violations % Non- Compliance Violations Per 100 Stop Cycles Followed Departing Queue Other Total With Flagger Without Flagger Total

19 Violation Data, cont. Site See Work Activity? See Other PTS? Followed Departing Queue Violations Per 100 Stop Cycles Other Total 1 No No & 4 Yes Yes Yes No

20 Preliminary Conclusions Only 2% of drivers did not comply No significant difference between violations with and without a flagger Violations appear to be impacted by what motorists can see Utilize a green time that allows the entire traffic queue present to clear More data being collected

21 Automate Flagger Assistance Devices (AFADs)

22 How Do Red/Yellow AFADs work? Stop Proceed Transition

23 How Do Stop/Slow AFADs work? Stop Proceed

24 Concerns Prior to Statewide Implementation Motorist not understanding AFADs Stop and then proceed like at a normal stop sign Red, flashing yellow, and steady yellow circular indications Decreased compliance Motorist misunderstanding Less respect for device Gate arm optional for stop/slow AFAD

25 Research study September August 2011 Assess effectiveness of AFADs Motorist surveys - comprehension Stop/slow AFAD Red/yellow lens AFAD Advance warning sign sequence Field studies - effectiveness Operational Safety

26 Motorist Surveys Main Findings Stop/slow AFADs Current signs not well understood Experimental symbol sign best understood Need to require gate arm Red/yellow lens AFADs Participants understood stop and proceed phases Most participants did not understand difference between flashing and steady yellow signals Gate arm critical to understanding

27 Field Study Main Findings Treatment Violations Per 100 Stop Cycles Flagger 0.0 Red/Yellow Lens AFAD 2.2 Stop/Slow AFAD WAIT ON STOP Sign (min. req.) Stop/Slow AFAD WAIT ON STOP Sign Gate Arm Stop/Slow AFAD WAIT ON STOP/GO ON SLOW Signs Gate Arm Stop/Slow AFAD Experimental Symbol Sign Gate Arm

28 Current Implementation Both types included in 2011 Texas MUTCD Developed AFAD standard sheet Only used where there is one approaching traffic lane Adequate stopping sight distance must be provided Must be operated by certified flagger Flaggers cannot leave unattended One flagger can operate two AFADs in certain cases MUTCD advance warning sign sequence used All AFADs must have a gate arm with flag Experimental symbol supplemental signs used

29 Implementation as of March

30 Questions Carl Johnson, P.E. TxDOT Melisa Finley, P.E. TTI AFAD Research Report