Innovative Designs for Improving Intersection Capacity · Ohio State Route 125/Five Mile Road,...
Transcript of Innovative Designs for Improving Intersection Capacity · Ohio State Route 125/Five Mile Road,...
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INNOVATIVE DESIGNS FOR INNOVATIVE DESIGNS FOR IMPROVING INTERSECTION IMPROVING INTERSECTION
CAPACITYCAPACITYPresented by Presented by
NazirNazir LalaniLalani P.E.P.E.TraffexTraffex Engineers Inc.Engineers [email protected][email protected]
AT GRADE INTERSETIONSAT GRADE INTERSETIONSContinuous Flow Intersections (CFI)Continuous Flow Intersections (CFI)
Parallel Flow IntersectionParallel Flow Intersection
Offset LeftOffset Left--turnsturns
Jug HandlesJug Handles
Median CrossoversMedian Crossovers
Split IntersectionsSplit Intersections
Quadrant ConnectorsQuadrant Connectors
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GRADE SEPARATEDGRADE SEPARATEDSingle Point Interchanges (SPUI)Single Point Interchanges (SPUI)
Tight Urban Diamond Tight Urban Diamond
Diverging DiamondDiverging Diamond
Echelon InterchangeEchelon Interchange
Grade Separated IntersectionsGrade Separated Intersections
Queue Jumping for Transit VehiclesQueue Jumping for Transit Vehicles
AT GRADE INTERSECTIONSAT GRADE INTERSECTIONS
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Continuous Flow Intersections Continuous Flow Intersections
Source: Fehr and Peers, Salt Lake City
LeftLeft--turns/thru movements turns/thru movements move togethermove together
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Source: KOA CorporationSource: KOA Corporation
This design includes crosswalks This design includes crosswalks but very long if timed as single phasebut very long if timed as single phase
Source: Fehr and Peers, Salt Lake City
LeftLeft--turns move across opposing lanes at turns move across opposing lanes at Half signal before the intersectionHalf signal before the intersection
Design is patented: US Design is patented: US 50490005049000
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Left-turns move to far left using a half signalso they can turn with thru- traffic
Half signal
http://www.abmb.com/cfi-testdrive.html
Half signal
CONTINUOUS FLOW CONTINUOUS FLOW INTERSECTIONINTERSECTION
LeftLeft--turns moved to the far left turns moved to the far left
LeftLeft--turns at same time as through movementsturns at same time as through movements
Eight phases reduced to fourEight phases reduced to four
Reduces conflicts at the main intersectionReduces conflicts at the main intersection
Improves capacity by up to 70%Improves capacity by up to 70%
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CONTINUOUS FLOW CONTINUOUS FLOW INTERSECTIONINTERSECTION
Four additional traffic signals needed Four additional traffic signals needed –– one on each one on each approach approach
Access to adjacent properties severely limitedAccess to adjacent properties severely limited
Right of way largerRight of way larger
Pedestrians may need to be grade separatedPedestrians may need to be grade separated
More complex for bicyclists More complex for bicyclists
RightRight--ofof--way impactsway impactsSource: KOA CorporationSource: KOA Corporation
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Locations in USALocations in USABaton Rouge, LouisianaBaton Rouge, Louisiana
Maryland Maryland –– Hwy 210Hwy 210
Ohio State Route 125/Five Mile Road, Hamilton CountyOhio State Route 125/Five Mile Road, Hamilton County
BangerterBangerter Hwy and 3500 South, Salt Lake City AreaHwy and 3500 South, Salt Lake City Area
“Continuous Flow Intersections”: ITE Journal, July 2004
Patent Holders: Francisco D. Patent Holders: Francisco D. MierMier and and BelisarioBelisario H. H. RomoRomo, ,
Baton Rouge, LouisianaBaton Rouge, Louisiana
Congestion Reduced by 40%Congestion Reduced by 40%
Volume thru intersection increased by 10%Volume thru intersection increased by 10%
Crashes reduced by 27%Crashes reduced by 27%
More information at :http://www.abmb.com/cfi-BR.html
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Baton Rouge, Louisiana (2006)
For more info: ABMB Engineering (www.abmb.com)
Four-way example in Mexico
LeftLeft--turns/thru movements turns/thru movements move togethermove together
Opposing traffic!
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Parallel Flow Intersections Parallel Flow Intersections
Source: Urban Transportation MonitorSource: Urban Transportation Monitor
LeftLeft--turns are on this side of the medianturns are on this side of the median
Simulation may be viewed at: Simulation may be viewed at: www.quadranteng.comwww.quadranteng.com
Design is patented: US Design is patented: US 71359897135989
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LeftLeft--turns made ahead of the intersection turns made ahead of the intersection
No left turn movements at the intersectionNo left turn movements at the intersection
Eight phases reduced to fourEight phases reduced to four
Reduces conflicts at the main intersectionReduces conflicts at the main intersection
Improves capacity by up to 70%Improves capacity by up to 70%
PARALLEL FLOW PARALLEL FLOW INTERSECTIONINTERSECTION
Up to at least additional traffic signals needed Up to at least additional traffic signals needed –– one one on each approach on each approach
Access to adjacent properties severely limitedAccess to adjacent properties severely limited
Right of way largerRight of way larger
Pedestrians crosswalks at intersectionPedestrians crosswalks at intersection
Not as complex for bicyclists Not as complex for bicyclists
PARALLEL FLOW PARALLEL FLOW INTERSECTIONINTERSECTION
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Gregory F. Parsons is the Patent Holder Gregory F. Parsons is the Patent Holder
Article published in the ITE Journal October 2007Article published in the ITE Journal October 2007
Additional information in the Urban Transportation Additional information in the Urban Transportation MonitorMonitor
No known operational intersections to dateNo known operational intersections to date
PARALLEL FLOW PARALLEL FLOW INTERSECTIONINTERSECTION
OFFSET LEFTOFFSET LEFT--TURNSTURNSBest suited for wide mediansBest suited for wide medians
Reduces leftReduces left--turn maneuver travel distanceturn maneuver travel distance
Improves visibility of onImproves visibility of on--coming trafficcoming traffic
Conversion to dual leftConversion to dual left--turns possibleturns possible
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(Michigan Left(Michigan Left--Turns)Turns)
Median Crossover Median Crossover
UU--turns median crossoversturns median crossovers
Source: Signalized Intersection Information GuideFHWA-HRT-04-091
Median CrossoverMedian Crossover RightRight--turn after crossoverturn after crossover
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MICHIGAN LEFTMICHIGAN LEFT--TURNTURN
Requires wide mediansRequires wide medians
Remove leftRemove left--turns from intersectionturns from intersection
Improves capacity and reduces collisions at Improves capacity and reduces collisions at the intersectionthe intersection
Vehicles have to go through intersection twiceVehicles have to go through intersection twice
Example in MichiganExample in Michigan
No left-turns are allowed at the signal
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Capacity Gains from Michigan UCapacity Gains from Michigan U-- Turns v. Dual LeftsTurns v. Dual Lefts
Source: NCHRP Report 420: Impacts of Access Management Techniques.
Super Street Median CrossoverSuper Street Median Crossover
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Super Street Median CrossoverSuper Street Median Crossover
Source: Signalized Intersection Information GuideFHWA-HRT-04-091
No through movements allowed from side streetNo through movements allowed from side street
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Left turns made as ULeft turns made as U--turnsturns
Signalized leftSignalized left--turns and rightturns and right--turnsturns onlyonly
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PrePre--signal Usignal U--turnturn
PRESIGNAL UPRESIGNAL U--TURNSTURNSRequires wider mediansRequires wider medians
Remove URemove U--turns from intersectionturns from intersection
Improves capacity and reduces collisionsImproves capacity and reduces collisions
Most effective where heavy UMost effective where heavy U--turns presentturns present
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JUGHANDLESJUGHANDLES
Near sideNear side
Far sideFar side
UU--TurnTurn
Indirect leftIndirect left--turnsturns
Forward Forward
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Near SideNear Side
Source: Signalized Intersection Information GuideFHWA-HRT-04-091
Left-turns taken out of main traffic stream
Source: KOA CorporationSource: KOA Corporation
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Source: Signalized Intersection Information GuideFHWA-HRT-04-091
Forward near sideForward near side
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Reverse Reverse
Far SideFar Side
Source: Signalized Intersection Information GuideFHWA-HRT-04-091
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REVERSEREVERSETraffic circulation more circuitousTraffic circulation more circuitous
Right of way needed for connectorRight of way needed for connector
Removes leftRemoves left--turns from the intersectionturns from the intersection
Merge distance needs to be greater than Merge distance needs to be greater than 500 feet. 500 feet.
UU--Turn Turn
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New regulatory signs for New regulatory signs for jughandlesjughandles
ALTERNATIVE INTESECTION ALTERNATIVE INTESECTION TREATMENTS TREATMENTS
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Quadrant Roadway Quadrant Roadway
Quadrant roadway intersectionQuadrant roadway intersectionSource: KOA Corporation
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CONNECTOR ROADSCONNECTOR ROADSPedestrian traffic more circuitousPedestrian traffic more circuitous
Significant impact on transit operationsSignificant impact on transit operations
Right of way needed for connectorRight of way needed for connector
Significant construction impactsSignificant construction impacts
Most often used in conjunction with railroad Most often used in conjunction with railroad crossing improvementscrossing improvements
Split Intersections/Frontage Roads Split Intersections/Frontage Roads
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Split IntersectionSplit IntersectionSource: KOA Corporation
SPLIT INTERSECTIONSPLIT INTERSECTIONSpace between roads should be about 300 to Space between roads should be about 300 to 500 feet500 feet
Minimal impact on peds and transit operationsMinimal impact on peds and transit operations
No impacts to adjacent land usesNo impacts to adjacent land uses
Significant construction impactsSignificant construction impacts
Can be first phase of grade separation projectCan be first phase of grade separation project
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Source: Signalized Intersection Information GuideFHWA-HRT-04-091
Frontage road alignment shifted to Frontage road alignment shifted to increase spacingincrease spacing
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Variable Lane SignVariable Lane Sign
Variable lane sign allows dual rights Variable lane sign allows dual rights during peak hoursduring peak hours
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Queue Jumping for Transit Vehicles Queue Jumping for Transit Vehicles
Source: Urban Transportation Monitor
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Bus priority lane in the NetherlandsBus priority lane in the Netherlands
QUEUE JUMPINGQUEUE JUMPINGBy pass lane requires additional right of By pass lane requires additional right of wayway
Significant reduction in delay on transit Significant reduction in delay on transit operationsoperations
More complex signal operationsMore complex signal operations
Best suited for short headway servicesBest suited for short headway services
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GRADE SEPARATED GRADE SEPARATED INTERSECTIONS INTERSECTIONS
Viaducts with Connector Roads Viaducts with Connector Roads
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Viaduct with connector roadwayViaduct with connector roadwaySource: KOA Corporation
CONNECTOR ROADSCONNECTOR ROADSPedestrian traffic more circuitousPedestrian traffic more circuitous
Significant impact on transit operationsSignificant impact on transit operations
Right of way needed for connectorRight of way needed for connector
Significant construction impactsSignificant construction impacts
Most often used in conjunction with railroad Most often used in conjunction with railroad crossing improvementscrossing improvements
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Viaduct with connector roadwaysViaduct with connector roadways
Movements between arterials made Movements between arterials made Via connector roadways Via connector roadways
Elevated LeftElevated Left--turns turns
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Center Turning OverpassCenter Turning OverpassSource: KOA CorporationSource: KOA Corporation
GRADE SEPARATED GRADE SEPARATED INTERSECTIONS INTERSECTIONS
Can be constructed within existing rightCan be constructed within existing right--ofof--wayway
Visual impacts to adjacent land usesVisual impacts to adjacent land uses
Merging movements from the leftMerging movements from the left
Addition ice and snow removal impactsAddition ice and snow removal impacts
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GRADE SEPARATED GRADE SEPARATED INTERSECTIONS INTERSECTIONS
Structure costs significantStructure costs significant
No significant impacts on No significant impacts on pedspeds or transitor transit
Little impacts on access to adjacent land usesLittle impacts on access to adjacent land uses
Construction impacts are minimalConstruction impacts are minimal
INTERCHANGESINTERCHANGES
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Single Point Urban Interchanges Single Point Urban Interchanges
SINGLE POINT URBAN SINGLE POINT URBAN INTERCHANGES (SPUI)INTERCHANGES (SPUI)
One intersection (above freeway better)One intersection (above freeway better)
Signals on overhead gantrySignals on overhead gantry
All turns handled in three movements All turns handled in three movements
More expensive (BIG retaining walls)More expensive (BIG retaining walls)
Reduced right of wayReduced right of way
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Single Point Urban InterchangeSingle Point Urban InterchangeLeft-turns take place under (or over) the main traffic stream
Source: KOA CorporationSource: KOA Corporation
SINGLE POINT URBAN SINGLE POINT URBAN INTERCHANGEINTERCHANGE
Requires the same area as a tight diamondRequires the same area as a tight diamond
Requires longer structureRequires longer structure
Significant impact on pedestrian trafficSignificant impact on pedestrian traffic
Significant impact on transit stop locationsSignificant impact on transit stop locations
Can be confusing to unfamiliar driversCan be confusing to unfamiliar drivers
Freeway underneath is preferred optionFreeway underneath is preferred option
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SPUI with freeway overheadSPUI with freeway overhead
View of SPUI from underneath the freewayView of SPUI from underneath the freeway(limits signal head visibility)(limits signal head visibility)
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SPUI in Phoenix with freeway underneathSPUI in Phoenix with freeway underneath(Preferred Design)(Preferred Design)
One signal processes three movements: Off-ramps/on-ramps/thru traffic
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Tight Urban Diamond InterchangeTight Urban Diamond Interchange(TUDI) (TUDI)
Spread DiamondSource: KOA CorporationSource: KOA Corporation
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Tight Urban Diamond
Source: KOA CorporationSource: KOA Corporation
TIGHT DIAMOND TIGHT DIAMOND INTERCHANGEINTERCHANGE
Reach capacity much sooner than SPUIs because Reach capacity much sooner than SPUIs because of special signal phasingof special signal phasing
Space between ramps about 100 feet vs. 300 feet Space between ramps about 100 feet vs. 300 feet for spread diamondsfor spread diamonds
Reduces conflicts at the main intersectionReduces conflicts at the main intersection
Can have some impacts on transit operationsCan have some impacts on transit operations
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Diverging Diamond InterchangeDiverging Diamond Interchange(DDI)(DDI)
http://www.oregonite.org/2007D6/paper_review/D9_44_Stanek_paper.pdf
DIVERGING DIAMOND DIVERGING DIAMOND INTERCHANGEINTERCHANGE
Unopposed left TurnsUnopposed left Turns
Closely Spaced IntersectionClosely Spaced Intersection
Separate Over crossingsSeparate Over crossings
Crossover IntersectionsCrossover Intersections
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http://www.435ddi.com/
I 435.Front Street, MoDOT
Source: Bared J. et al., Source: Bared J. et al., ““ Design and Operational Performance of Double Design and Operational Performance of Double Crossover Intersection and Diverging Diamond InterchangeCrossover Intersection and Diverging Diamond Interchange””
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Video Link: https://www.nysdot.gov/portal/page/portal/regional-offices/region4/projects/590winton/diverging-diam
I 590 and Winton Road, NYDOT
I-40/San Mateo Boulevard Interchange in Albuquerque, NMSource: NMDOTSource: NMDOT
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http://http://www.youtube.com/watch?vwww.youtube.com/watch?v=NANacKPO0Q4=NANacKPO0Q4
DIVERGING DIAMOND DIVERGING DIAMOND INTERCHANGEINTERCHANGE
21 conflict points v. 45 with TUDI21 conflict points v. 45 with TUDI
Smaller ramp intersections Smaller ramp intersections –– reduced clearance reduced clearance intervalsintervals
Un opposed left turns eliminates need for triple leftsUn opposed left turns eliminates need for triple lefts
Eliminates need for retain wallsEliminates need for retain walls
Better sight distanceBetter sight distance
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DIVERGING DIAMOND DIVERGING DIAMOND INTERCHANGEINTERCHANGE
Need public education campaign because of Need public education campaign because of unusual configurationunusual configuration
Pedestrians have to cross free flowing ramps Pedestrians have to cross free flowing ramps ––merging may require more than two manes in each merging may require more than two manes in each direction between the rampsdirection between the ramps
More intense level of signing, striping and lightingMore intense level of signing, striping and lighting
Limited accident history availableLimited accident history available
Echelon InterchangeEchelon Interchange
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UNDER
OVER
Left-turns taken out of main traffic stream through grade separation
Source: KOA CorporationSource: KOA CorporationEchelon Interchange
ECHELON INTERCHANGEECHELON INTERCHANGE
Needs wide rightNeeds wide right--ofof--wayway
For heavy turning movement locationsFor heavy turning movement locations
Limits access to adjacent land uses in some Limits access to adjacent land uses in some quadrantsquadrants
Appears confusing but all travel patterns are intuitiveAppears confusing but all travel patterns are intuitive
Construction impacts can be severerConstruction impacts can be severer
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RoundaboutsRoundabouts
ROUNDABOUT ROUNDABOUT INTERCHANGEINTERCHANGE
Shorter StructureShorter Structure
Efficient OperationEfficient Operation
Frontage Road Impacts MinimizedFrontage Road Impacts Minimized
Minimal DelaysMinimal Delays
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Roundabouts at an InterchangeRoundabouts at an Interchange
Roundabouts at an InterchangeRoundabouts at an Interchange
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http://www.teachamerica.com/RAB08/RAB08S9AThibault/index.htmhttp://www.teachamerica.com/RAB08/RAB08S9AThibault/index.htm
PEDESTRIAN ACCESSIBILTY ISSUESPEDESTRIAN ACCESSIBILTY ISSUES
US Access Board Concerns about free flowing intersections such aUS Access Board Concerns about free flowing intersections such as roundaboutss roundabouts
INTERCHANGE COMPARISONINTERCHANGE COMPARISON
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Interchanges Types IncludedInterchanges Types Included
Single Point Diamond (SPUI)Single Point Diamond (SPUI)
Roundabout DiamondRoundabout Diamond
Diverging DiamondDiverging Diamond
Source: Source: ““Innovative Diamond Interchange Designs: How to Innovative Diamond Interchange Designs: How to Increase CapacityIncrease Capacity”” and Minimize Cost and Minimize Cost –– David David StanekStanek
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When to Consider Innovative When to Consider Innovative InterchangeInterchange
Single Point Diamond (SPUI)Single Point Diamond (SPUI)
High leftHigh left--turn volumes > 300 vph at ramp turn volumes > 300 vph at ramp terminalsterminals
Signal progression on cross street importantSignal progression on cross street important
Adjacent signalize intersections closely Adjacent signalize intersections closely spacedspaced
When to Consider Innovative When to Consider Innovative InterchangeInterchange
Roundabout DiamondRoundabout Diamond
Low leftLow left--turn volumes < 300 vph at ramp terminalsturn volumes < 300 vph at ramp terminals
Need to minimize structure wideningNeed to minimize structure widening
Need to accommodate Need to accommodate pedspeds and bikesand bikes
Adjacent signalize intersections closely spacedAdjacent signalize intersections closely spaced
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When to Consider Innovative When to Consider Innovative InterchangeInterchange
Diverging DiamondDiverging Diamond
High leftHigh left--turn volumes > 300 vph at ramp terminalsturn volumes > 300 vph at ramp terminals
Need to minimize structure widening (potentially)Need to minimize structure widening (potentially)
Signal progression on cross street not importantSignal progression on cross street not important
OVERVIEW OF INNOVATIVE OVERVIEW OF INNOVATIVE DESIGNSDESIGNS
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Visit Visit http://attap.umd.edu/UAID.phphttp://attap.umd.edu/UAID.php for an for an excellent overview of alternative designsexcellent overview of alternative designs
REFERENCE LIST FOR SOURCES REFERENCE LIST FOR SOURCES OF INFORMATIONOF INFORMATION