Presentation on theme: "Traffic Topics Does the Zipper Merge threaten our way of life? Ken E. Johnson 651-234-7386 Office of Traffic, Safety and Technology."— Presentation transcript:
Traffic Topics Does the Zipper Merge threaten our way of life? Ken E. Johnson Office of Traffic, Safety and Technology
Recent media attention: Turns out those jerks were right… –Pioneer Press 5/17/10 Ive seen a threat to our very way of life – The Zipper Merge –Joe Soucheray 5/23/10 Zipper Merge
Why Zipper Merge? What are the benefits? What have been the problems? Where are we and what is Mn/DOT doing?
Zipper Merge: Merging behavior where drivers are encouraged to use both lanes prior to defined merge area Active Zipper Merge: Sensors and intelligence telling drivers when to use the Zipper Merge Passive Zipper Merge: Signs or PCMS notifying drivers to use Zipper Merge when backups occur Terminology
Why Zipper? Existing Merging Problems Backups Can extend beyond the advance warning signs when motorists queue up in a single lane Can block access or interchanges Rear end crashes caused by: Traffic flow disruptions caused by erratic merging along the entire length of the queue during backups Speed differential between lanes Increased Road Rage against those cheaters Self-appointed cops straddling lanes Its perfectly legal…
This scenario commonly occurs during lane closures Why Zipper?
Preferred Traffic Flow Utilizing Equal Lane Occupancy Why Zipper?
2004 Dynamic Late Merge Study Four Deployments: Four Deployments: I-494 Northbound in Plymouth I-494 Northbound in Plymouth I-494 Southbound in Plymouth I-494 Southbound in Plymouth US 52 in St. Paul US 52 in St. Paul I-35 around Lakeville I-35 around Lakeville Evaluation of 2004 Dynamic Late Merge System by URS Evaluation of 2004 Dynamic Late Merge System by URS Why Zipper?
Dynamic Late Merge Study (2004) Before and After Deployment Why Zipper? DOT%20Video%20DLMS.mpg
Findings and Results of 2004 Dynamic Late Merge Study Not enough info to evaluate crashes but it was clear: Not enough info to evaluate crashes but it was clear: Reduced aggressive driving Reduced aggressive driving Less confusion Less confusion Queue Lengths were reduced by 40% Queue Lengths were reduced by 40% Lane occupancy increased everyday during congestion - reached near equal lane occupancy after short duration Lane occupancy increased everyday during congestion - reached near equal lane occupancy after short duration Throughput not increased – 1600 vph Throughput not increased – 1600 vph Why Zipper?
Passive Zipper Merge Signs added: Signs added: USE BOTH LANES DURING BACKUPS USE BOTH LANES DURING BACKUPS TAKE TURNS AT MERGE TAKE TURNS AT MERGE Used over the past few years successfully Used over the past few years successfully I-35 between Pine City and Hinckley I-35 between Pine City and Hinckley I-35 near Faribault and Owatonna I-35 near Faribault and Owatonna Hastings bridge maintenance project Hastings bridge maintenance project State Highway 61 in St. Paul Park State Highway 61 in St. Paul Park I-494 in Woodbury I-494 in Woodbury Similar benefits to what was found in the DLMS Similar benefits to what was found in the DLMS Why Zipper?
Expected Benefits Speed differential reduced No Zipper - 1 lane stop and jerk and 1 lane fast Both lanes moving at same speed Reduced length of queue Theoretically up to 50% Reduced blocking of accesses and interchanges Fair Both lanes are equally disadvantaged by the backup Reduced Road Rage More protection for work area when both lanes have queues But – it wont get you through faster
Problems? Inconsistent application Some mixed messages Advance warning sign that tells the driver which lane is closed Some road rage issues even at locations signed for Zipper Online Community Surveyed Statewide Work Zone Safety Committee We know it works, what can we do? 80% Early Mergers 2/3 unhappy about late mergers 14% would block late mergers 40% Zipper Merge concept is new to them
Where are we? What is Mn/DOT doing? Decision made: Work to change typical driver behavior to do the Zipper Merge as standard When driving highway speeds – merge early When backups occur – use both lanes How: Public education effort More standard implementations of Zipper Merge Construction Maintenance In Metro – will implement when volumes exceed 1800 vph (Lane Closure Manual)
Where are we? What is Mn/DOT doing? CO Communications: Working to develop Public Education blitz CO Traffic: Created layout for Field Manual Trying to get funding for signs for Maintenance Construction: Received Destination Innovation Funding to implement for 2011 construction projects Active Zipper Merge systems in Metro projects Stopped Traffic Ahead systems in Greater MN projects Maintenance: Implement Zipper Merge where appropriate
Resources… Handout available on web: Late Merge…the Zipper System Google mndot zipper Layouts in the Field Manual Dynamic Late Merge System information Dynamic Late Merge System Evaluation DLMS Video
Not the only ones Taupo, New Zealand – Courtesy of Derrick Dasenbrock
Final thought… When you go to the grocery store – what line do you get into? Why are highway projects different?