Presentation on theme: "Traffic Topics Does the Zipper Merge threaten our way of life. Ken E"— Presentation transcript:
1Traffic Topics Does the Zipper Merge threaten our way of life. Ken E Traffic Topics Does the Zipper Merge threaten our way of life? Ken E. Johnson Office of Traffic, Safety and Technology
2Zipper Merge Recent media attention: “Turns out those “jerks” were right…”Pioneer Press 5/17/10“I’ve seen a threat to our very way of life – The Zipper Merge”Joe Soucheray 5/23/10We are competing with the world for our message.
3What have been the problems? Where are we and what is Mn/DOT doing? Why Zipper Merge?What are the benefits?What have been the problems?Where are we and what is Mn/DOT doing?We are competing with the world for our message.
4TerminologyZipper Merge:Merging behavior where drivers are encouraged to use both lanes prior to defined merge areaActive Zipper Merge:Sensors and intelligence telling drivers when to use the Zipper MergePassive Zipper Merge:Signs or PCMS notifying drivers to use Zipper Merge when backups occur
5Existing Merging Problems Why Zipper?Existing Merging ProblemsBackupsCan extend beyond the advance warning signs when motorists queue up in a single laneCan block access or interchangesRear end crashes caused by:Traffic flow disruptions caused by erratic merging along the entire length of the queue during backupsSpeed differential between lanesIncreased Road Rage against those “cheaters”Self-appointed “cops” straddling lanesIt’s perfectly legal…
6This scenario commonly occurs during lane closures Why Zipper?This scenario commonly occurs during lane closures
7Preferred Traffic Flow — Utilizing Equal Lane Occupancy Why Zipper?Preferred Traffic Flow — Utilizing Equal Lane Occupancy
82004 Dynamic Late Merge Study Why Zipper?2004 Dynamic Late Merge StudyFour Deployments:I-494 Northbound in PlymouthI-494 Southbound in PlymouthUS 52 in St. PaulI-35 around LakevilleEvaluation of 2004 Dynamic Late Merge System by URS
9Dynamic Late Merge Study (2004) Before and After Deployment Why Zipper?Dynamic Late Merge Study (2004)Before and After Deployment
10Findings and Results of 2004 Dynamic Late Merge Study Why Zipper?Findings and Results of Dynamic Late Merge StudyNot enough info to evaluate crashes but it was clear:Reduced aggressive drivingLess confusionQueue Lengths were reduced by 40%Lane occupancy increased everyday during congestion - reached near equal lane occupancy after short durationThroughput not increased – 1600 vph
11Passive Zipper Merge Why Zipper? Signs added: USE BOTH LANES DURING BACKUPSTAKE TURNS AT MERGEUsed over the past few years successfullyI-35 between Pine City and HinckleyI-35 near Faribault and OwatonnaHastings bridge maintenance projectState Highway 61 in St. Paul ParkI-494 in WoodburySimilar benefits to what was found in the DLMS
12Expected Benefits Speed differential reduced No Zipper - 1 lane stop and jerk and 1 lane fastBoth lanes moving at same speedReduced length of queueTheoretically up to 50%Reduced blocking of accesses and interchangesFairBoth lanes are equally disadvantaged by the backupReduced Road RageMore protection for work area when both lanes have queuesBut – it won’t get you through faster
13Problems? Inconsistent application Some mixed messages Advance warning sign that tells the driver which lane is closedSome road rage issues even at locations signed for ZipperOnline Community Surveyed80% Early Mergers2/3 unhappy about late mergers14% would block late mergers40% Zipper Merge concept is new to themStatewide Work Zone Safety CommitteeWe know it works, what can we do?
14Where are we? What is Mn/DOT doing? Decision made: Work to change typical driver behavior to do the Zipper Merge as standardWhen driving highway speeds – merge earlyWhen backups occur – use both lanesHow:Public education effortMore standard implementations of Zipper MergeConstructionMaintenanceIn Metro – will implement when volumes exceed 1800 vph (Lane Closure Manual)
17Where are we? What is Mn/DOT doing? CO Communications: Working to develop Public Education blitzCO Traffic:Created layout for Field ManualTrying to get funding for signs for MaintenanceConstruction:Received Destination Innovation Funding to implement for 2011 construction projectsActive Zipper Merge systems in Metro projectsStopped Traffic Ahead systems in Greater MN projectsMaintenance:Implement Zipper Merge where appropriate
18Resources… Handout available on web: Late Merge…the Zipper System Google mndot zipperLayouts in the Field ManualDynamic Late Merge System informationDynamic Late Merge System EvaluationDLMS Video
19Taupo, New Zealand – Courtesy of Derrick Dasenbrock Not the only onesTaupo, New Zealand – Courtesy of Derrick Dasenbrock
20Final thought…When you go to the grocery store – what line do you get into?Why are highway projects different?