Work Zone Detection

Brian Kary and Terry Haukom - RTMC

Provide Delay Information To Motorists

Potential for Diversion

Perception Tracking Survey Results

Why Do It

Page 3Base = 602 unless otherwise noted

The Dieringer Research Group, Inc.Prepared for MnDOT, September 2012

Perception Tracking StudyWave XI: July-August 2012 Phone Survey

Travel Time Messages – Ratings & Comments

• Overall, drivers continue to consider displaying travel time information on overhead electronic signs to be a good idea. There is a significant increase in the

proportion of drivers who consider displaying travel time messages an “Excellent” idea.

2012N=602

2011N=600

# % # %

Top 4 Box 472 78% 487 81%

Excellent Idea (10) 269 45% 230 38%

9 42 7% 60 10%

8 107 18% 124 21%

7 54 9% 73 12%

6 19 3% 17 3%

5 53 9% 46 8%

4 9 2% 9 2%

3 8 1% 12 2%

2 12 2% 5 1%

Poor Idea (1) 10 2% 11 2%

Bottom 4 Box 39 7% 37 6%

Don’t Know 19 3% 13 2%

Q71d. How would you rate the idea of posting travel TIME information on overhead electronic signs as a tool to manage traffic?

Mean = 8.19 Mean = 8.12*Totals may not equal 100% due to rounding. Data noted with arrow is significantly lower or higher respectively than 2011 at the 95% confidence level.

All Drivers

N = Base # = Frequency

Page 4Base = 602 unless otherwise noted

The Dieringer Research Group, Inc.Prepared for MnDOT, September 2012

Perception Tracking StudyWave XI: July-August 2012 Phone Survey

Travel Time Messages - Actionability

*Totals may not equal 100% due to rounding. Data noted with arrow is significantly lower or higher respectively than 2011 at the 95% confidence level.

2012N=398

2011N=393

# % # %

Almost always 74 19% 54 14%

Sometimes 155 39% 183 47%

Rarely 125 31% 119 30%

Never 43 11% 35 9%

Don't Know 1 <1% 2 1%

Q71b. How often, if at all, do you take an ALTERNATE ROUTE because a travel time message on an overhead electronic message sign showed a longer time than your usual time for the trip?

58%

• Among those drivers who make a route decision based on a travel time message, nearly 6 in 10 chose to take an alternate route at least some of the time.

Have Made an Alternate Route Decision Based on Time Message Info

N = Base # = Frequency

Proven Method of Calculating Travel Times

Reduced Costs◦ Utilize existing 150+ DMS◦ Utilize detection outside of work zone

Currently have 400 miles of freeway instrumented with loop detection

Future detection will utilize more Wavetronics sensors which may allow detection within work zones

Traveler Information

Why Integrate with RTMC?

Traveler Information• Traveler Information Websites

• Smart Phone Apps

Traveler Information• Traffic Reports

• Travel Times Signs

Wavetronics Sensor

Camera Wireless Modem Solar Power

Detection Trailer

Travel Time ZoneDistance BetweenStations = ½ mile

Distance BetweenStations = ½ mile

Error Caused by Increased SpacingBetween 55 MPH and 5 MPH

Spacing Distance Time Error (Minutes)1/2 5.5

1 10.92 21.85 54.5

Included in Main Project – Lump Sum◦ I-35E – From CR 96 to I-35

$250,000◦ I-694 – From Hwy 61 to Hwy 5

$185,000

Separate Project◦ I-494 – From Hwy 100 to 34th Ave (SP 2785-392)

$262,300

Past Projects

Not enough lead time for integration

Lack of communications about traffic switches

Inadequate detection methods◦ Increased detection spacing◦ Probe data

Issues with Past Projects

Total Project Estimated Cost - $750,000

Provide one prototype trailer.

SP 0285-65 on I-694 from Hwy 252 to I-35W.  ◦ Provide 16 trailers.

SP 1982-161 on I-35E from I-35 south split to Cliff Rd.  ◦ Provide 8 trailers.  

SP 2776-103 Hwy 169 River Bridge.  ◦ Provide 18 trailers plus 3 PCMS.

SP 7080-51, 7080-50 on I-35 from District Border to I-35 south split.  ◦ Provide 30 trailers which includes 3 w/ cameras plus 3 PCMS. 

Metro Wide Project - SP 8825-465

Questions?Brian Kary

Freeway Operations Engineerbrian.kary@state.mn.us

Terry HaukomRTMC Design and Maintenance Supervisor

terry.haukom@state.mn.us