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

Modified Hybrid Device

Stop Proceed Left

Transition

Blank-Out Sign

Stop Proceed Right

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

Pilot Field Study Location

CR 418

FM 916

Pilot Field Study Location, cont.

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 m-finley@tti.tamu.edu

Research report available at http://tti.tamu.edu/documents/ 0-6708-1.pdf

TRB paper 16-0682