kentucky's 1st double crossover diamond interchange

Kentucky’s First DCD Interchange: One Year Later

SEAUPG Annual Meeting

November 13, 2012

http://transportation.ky.gov/us-68-double-crossover-diamond

Kentucky’s First DCD InterchangeOne Year Later

• Project Background

• Project Schedule

• Post-Construction Findings

Project LocationTo Downtown

To Man o’War Blvd.

Project Corridor

2,000’

Project Issues

1.High Crash Rate

2.Heavy Through Movement on Harrodsburg Road

3.Heavy Left-Turn Movements onto New Circle

SEAUPG ANNUAL MEETING SESSION III-INTERESTING PROJECTS NOVEMBER 14, 2012

Shared-Use Paths Previous Interchange Layout

DCD Interchange Layout Project Schedule

Public Meeting #1 March 29, 2011

Project Letting May 20, 2011

Public Meeting #2 June 23, 2011

Traffic Pattern Shift August 14, 2011

All Lanes Open October 9, 2011

Construction Complete November 15, 2011


Contract Notes on Maintenance of Traffic

LANE CLOSURES SHALL NOT BE ALLOWED DURING THE HOURS OF 6:00 AM TO 7:00 PM MONDAY THROUGH FRIDAY…

TRAFFIC SHALL BE SHIFTED TO THE ULTIMATE CONFIGURATION PRIOR TO AUGUST 31, 2011. LIQUIDATED DAMAGES OF $5000.00/HOUR WILL BE ASSESSED UNTIL THIS HAS OCCURRED.

Inner Loop Entrance Ramp

Inner Loop Exit Ramp Outer Loop Exit Ramp

Friday, August 12 Saturday, August 13


Opening Morning Monday Morning Rush Hour

Project Cost

• Engineer’s Estimate: $5.79 M

• Winning Bid: $5.67 M– ATS Construction – 4,400 tons of surface– 7,825 tons of base

Lesson Learned #1: Unavoidable Conditions

• Unsuitable subgrade material– Difficult to predict– Subgrade

manipulation not always feasible

Lesson Learned #2: Utilities

• Subsurface Utility Exploration (SUE)– Urban areas– Tight constraints– Not cleared before

construction

Lesson Learned #3: Contractor Input

• Contractor Input prior to Letting– KY Contractors

Association– Aggressive schedules


Post-Construction

• Crash Data

• Traffic Operations

• Public Feedback

Crash Data*

*Includes all reported crashes between Beaumont Centre Parkway and Alexandria Drive.

Averaged 10.3 crashes per month from 2008 - 2011

Crash Data

We’re averaging 45% fewer crashes with the DCD interchange.

Crash Types – Jan. 1 – June 30, 2012

AM Traffic – Pre-DCD

Common backups to Wellington

Way

Backups well beyond Snaffle

RoadBackups onto

New Circle Road

AM Traffic – Post-DCD

Ramps back up mid-way

Backups rarely extend halfway to

Fort Harrods from Corporate

Drive

Beaumont Centre completely clears


KYTC Survey: Over 1,400 responses Overall, do you think this project was a good transportation solution for this location?

72% said it was a good solution

Do you think a DCD interchange should be considered at other locations in Lexington or

elsewhere in Kentucky?

72% said a DCD should be considered elsewhere

Other DCD’s under Design in KY

• KYTC District 6 is designing two DCD’s along I-75 in Boone County

Inner Loop Crossover Inner Loop Crossover




Contact Information

Brian Aldridge, P.E.

Stantec Consulting Services10509 Timberwood Circle Suite

100Louisville, KY 40223

[email protected]: (502) 212-5000

http://transportation.ky.gov/us-68-double-crossover-diamond

Jason Bricker, P.E.

Stantec Consulting Services400 East Vine Street

Suite 300Lexington, KY 40507

[email protected]: (859) 233-2100

November 2012


November 2012 Acknowledgements

• KYTC Central Office Highway Design• Jeff Jasper• Keith Caudill

• KYTC District 7• James Ballinger• Bob Nunley• Steve Farmer • Tony McGaha

• KYTC Central Office Traffic• Jeff Wolfe• Lynn Witmer• Ted Swansegar

• LFUCG Division of Traffic• Steve Cummins• Jeff Neal • Billy Treadway• Joel Weber

January 30, 2012 January 30, 2012


PM Traffic – Pre-DCD

Corporate queues for about 35

minutes

Backups well beyond Larkspur

Drive

Heavy congestion on Beaumont

Centre Parkway

Heavy congestion for left turns onto

New Circle

PM Traffic – Post-DCD

Queues to Burbank clear in one signal cycle

Beaumont Centre clears in signal

cycle

Corporate queues for about 15

minutes

Free flow left-turn lanes reduce

congestion

Crossing Angle

• Missouri DOT

40 – 50 degrees

I-270 at Dorsett Ave, St. Louis, MO

Bicycle and Pedestrian Accommodations Positive Feedback“I am writing to commend ENTRAN and the KYTC for their work on the DCD interchange on US 68 in Lexington, KY.

… information presented at multiple public meetings, on the project website, and through local media outlets helped me understand how the design works and educated countless citizens about the project.

… The interchange has improved safety, reduced traffic congestion, and made a significant step in connecting Lexington’s expanding bicycle and pedestrian network.”

Lexington-Fayette Urban County Government Councilman Doug Martin


Positive Feedback

“Sadly, I'm hearing the same pessimistic commentary that I did when they were building the Frankfort Pike round-about. Those naysayer's are nowhere to be found now that it's finished and isworking like a charm. No one ever said that the "DCD" would cure all the problems at this particular intersection, but rather that it would reduce a significant amount of the rush hour congestion. From what I've observed during its construction and 3 trips through the intersection (one at morning rush hour), this too isdestined to achieve what was intended by the design.”

Read more here: http://www.kentucky.com/2011/08/15/1846182/motorists-navigate-new-harrodsburg.html#storylink=cpy

Typical Sections – Beneath New Circle

Typical Sections – At Crossovers Curvature & Crossing Angle

New Circle Road Outer Loop Exit

Ramp

Curvature & Crossing Angle


Morning Peak Hour Simulation

Existing (2007)

Existing AM

DCD

Existing AM

• 484 Reported crashes– 388 rear end

crashes (80%) – 48 Sideswipe

crashes (10%)– 90 injury crashes

(19%)

Crash HistoryJanuary 1, 2008 – December 31, 2010

Outer Loop Exit Ramp Outer Loop Exit Ramp


Peak Hour Traffic Counts

Peak Hour traffic is 20% to 40% higher than before the project began in 2007.

2007 AM Peak Hour Counts

2007 PM Peak Hour Counts

No Turns on Red

Source: Missouri’s Experience with a Diverging Diamond Interchange, Lessons Learned

Expected Oncoming

Traffic

Actual Oncoming

Traffic


Weaving Condition 2006 Congestion Management Study: Tates Creek Rd. at New Circle Rd.

• Increased capacity 15% - 25%

• Delay reduced by as much as 65%

Two-Phase Signal Operation Two-Phase Signal Operation

Left turns are free-flow Conflict Points are Reduced

● DCD– 2 crossing

conflict points

● Conventional– 4 crossing

conflict points


East of Pasadena Drive

I-44 at SR 13, Springfield, MO I-44 at SR 13, Springfield, MO

Source: http://www.usatoday.com/news/nation/2010-01-27-diverging-diamond-interchange_N.htm

• Opened 6/21/09• Cost: $2.9M• SR 13 - 29,000

vehicles per day• Crashes decreased by

60% from 2008

• 4 others have since opened in Missouri

Meeting with MoDOT


kentucky's 1st double crossover diamond interchange

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