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Temporary Traffic Control at Access Points
within Alternating One-Way Operations
Melisa Finley TTI Research Engineer
January 11, 2016 TRB 2016 Annual Meeting
The Problem
Lane closures on two-lane, two-way roads
• Control one-way operation at each end
• What about low-volume access points?
Existing methods are not always feasible
• Work duration
• Traffic volume
• Time of day
• Cost
Evaluation
Surveys to determine driver understanding
Field studies to assess operational and safety effectiveness
Motorist Surveys
Video sequences of mock devices on laptop
320 participants
Each participant only saw one device
Motorist Survey Results
Verified need for NO TURN ON RED sign with modified hybrid device
Better motorist understanding of the blank-out sign for
• Direction could not turn during stop phase
• Direction could turn during proceed phase
• Direction vehicles on main road were traveling during proceed phase
How Did the Devices Work?
Used in conjunction with portable traffic signals (PTS)
PTS Northbound PTS Southbound Driveway Device
Green Red Allows NB turns
Red Red Allows NB turns
Red Red Red
Red Green Allows SB turns
Red Red Allows SB turns
Red Red Red
What We Did
Controlled study (n=16)
• Participants recruited by TTI
• Only saw one device
• Began with observation phase
• Ended with survey at device
Non-controlled study (n=52)
• Drivers on the road
• Researcher located off the roadway
Response
Controlled - Sample size* - Correct action - Incorrect action
7
57% 43%
7
100% 0%
Non-controlled - Sample size - Correct action - Incorrect action
39
87% 13%
13
77% 23%**
Observation Results
* Two participants’ data removed due to potential interference.
**Two occurrences (15%) attributed to incorrect timing of device.
Response
(n=8)
(n=8)
Can turn onto the main road 100% 88%
Correct turn direction 100% 88%
Correct main road vehicle direction 100% 88%
Yield to main road 100% 100%
Come to complete stop before turning NA 100%
Field Study Survey Results: Proceed Phase
NA = Not Applicable
Field Study Survey Results: Stop Phase
Response
(n=8)
(n=8)
Cannot turn onto main road 100% 100%
Cannot turn right or left 100% 100%
Remain stopped until otherwise indicated 88% 88%
Summary
Flashing yellow arrow design not as well understood • 43% of participants reacted incorrectly
• 13% of other drivers reacted incorrectly
• 10% of other drivers had to ask what to do
Blank-out sign design better understood • 0% of participants reacted incorrectly
• 8% of other drivers reacted incorrectly once programming fixed
Additional Research Needed
More data
Potential changes to devices
Driver understanding
Location of device
Conflicts with existing traffic control devices
Appropriate coordination with PTS on main road
Contact Information
Melisa D. Finley, P.E. 979-845-7596 [email protected]
Research report available at http://tti.tamu.edu/documents/ 0-6708-1.pdf
TRB paper 16-0682