Multilane Highways and Freeways - Purdue University

HCM 2000 Course

Multilane Highways and Freeways

Lectures

Instructor Andrew P. Tarko

Teaching Assistant

Tim Wells

Purdue University West Lafayette, Indiana

June 19-21, 2006

M-1

Chapter 21 Multilane Highways

Instructor: Andrew P. Tarko

Short Course on Highway Capacity ManualPurdue UniversityWest Lafayette, June 19-21, 2006

Outline

ConceptsMethodologyHCS Exercises

M-2

Concepts

ConceptsMultilane Highways

Four or six lanesIn rural or suburban areasNo traffic signalsNo stop signsUnsignalized intersectionsAccess points

M-3

ConceptsInput Data

ConceptsIdeal Conditions

12-ft minimum lane widths12-ft minimum total lateral clearance in the direction of travel (lateral clearances greater than 6 ft are considered equal to 6 ft)Only passenger cars in the traffic streamNo direct access points along the roadwayA divided highwayLevel terrain

M-4

ConceptsSpeed-flow Curves and LOS

FFS = 50 mi/hV=1,000 pc/h/ln

ConceptsFree-flow Speed

Base FreeFlow Speed

Effect ofLane Width

Effect of Lateral Clearance

Effect ofMedian

Effect of AccessPoints

Free FlowSpeed

M-5

ConceptsFlow Rate

Flow Rate

PeakHourFactor

Numberof Lanes

Effect ofDriverPopulation

HourlyVolume

Effect of Heavy Vehicles on Grades

PC Equivalentfor Trucks andBuses

PC Equivalentfor RecreationalVehicles

ConceptsTraffic Density

vp=1,600 pc/h/lnFFS = 52.5 mi/hS = 51.0 mi/h D = 1,600/51.0D = 31.4 pc/mi/ln

M-6

Methodology

MethodologyInput

4-lane undivided highway,45 mi/h speed limit,11-ft lane width,26 access points along 3.25 mi4-ft outside shoulder,2.5 percent 2,100 ft grade,1,900-veh/h volume,13 percent trucks and buses,2 percent RVs, and0.90 PHF.LOS ?

M-7

MethodologyFree Flow Speed

4-lane undivided highway,45 mi/h speed limit,11-ft lane width,4 ft outside shoulder,26 access points along 3.25 mi,

BFFS = 45 + 7 = 52 mi/h



Density of access points = 26/3.25 = 8 per mile

2.0 mi/h

M-8



FFS = 52 – 1.9 – 1.6 – 2.0 – 0.4 = 46.1 mi/h

Total lateral clearance is:4 + 6 = 10 ft

MethodologyFlow Rate

4 lanes,2.5 percent 2,100 ft grade,1,900-veh/h volume,13 percent trucks and buses,2 percent RVs, and0.90 PHF.

M-9

MethodologyFlow Rate

Methodology LOS

FFS = 46.1-mi/h calculated vp = 1,129 pc/h/ln flow rate

S = 46.1 mi/hD = vp/SD = 1,129/46.1D = 24.5 pc/mi/ln

M-10

HCS

Demonstration of the example presented in class

Exercise - US 52 Studied Segment

LafayetteFuture needs of widening of the U.S. Highway 52 south of Lafayette, Indiana, are to be studied.

M-11

Exercise - US 52 Studied Segment

The segment 2.8 miles long in Tippecanoe County between CR 350 S and CR 550 S is considered in this exercise.

Exercise - US 52 Geometry and Pavement

• Full-depth asphalt pavement with painted striping

• Two 12-foot travel lanes

• Divided cross-section with 6 feet of left-side clearance

• 2-foot right shoulders

• Ten residential and commercial access points along highway section in the Southbound direction

• Slightly rolling vertical alignment without pronounced grades

M-12

Exercise - US 52 Traffic

2003 AADT = 10,780 veh/day,5% trucks, 1% recreational vehicles,Local traffic prevails,12% of AADT during the hour of analysis,60% traffic in the SB direction,PHF = 0.92,Speed limit is 55 mph, andAnnual traffic growth factor = 3 %.

Exercise - US 52 Tasks

1. Please check the present traffic conditions in the peak direction during the afternoon rush hour.

2. Determine in which year the studied US 52 segment may require upgrading to accommodate increased traffic. LOS C is the minimum requirement.

M-13

END

of multilane highways

F-1

Chapter 22 Freeway Facilities



Outline


F-2

ConceptsDemand vs. Volume

Volume = actual number of vehicles passing a spot per hour

Demand = volume that does not reflect the effects of upstream bottlenecks and downstream queues

ConceptsEffect of Overflow

Vr= 800 veh/h

Vf =6,600 C3 = 7,100C1 = 7,000 C3 = 6,200+800

Basic Segment 1 1.0 mi

Basic Segment 21.0 mi

Ramp JunctionSegment0.3 mi

Section 1 Section 2

var

41

37

Densityveh/mi/ln

7,100

6,200+800

7,000

Capacityveh/h

F7,400Basic 2

F6,600+800Ramp Junction

E6,600Basic 1

LOSDemandveh/h

Segment

Standard Analysis Results

3 lanesnear-basic conditions

F-3

Basic Segment 1 1.0 mi

Basic Segment 21.0 mi

Vr= 800 veh/h

Vf =6,600 C3 = 7,100C1 = 7,000 C3 = 6,200+ 800

Ramp JunctionSegment0.3 mi

Section 1 Section 2

0

0

200

Av. Queue veh

43

39

55

Densityveh/mi/ln

7,100

6,200+800

7,000

Capacityveh/h

E7,000Basic 2

E6,200+800Ramp Junction

F6,600Basic 1

LOSInflowveh/h

SegmentResults with Consideration of Queues (1 hr)

3 lanesnear-basic conditionsAfter one hour

400 veh remain


6,200 veh/henter

7,000 veh/h enter


var

41

37

Densityveh/mi/ln

7,100

6,200+800

7,000

Capacityveh/h

F7,400Basic 2

F6,600+800Ramp Junction

E6,600Basic 1

LOSDemandveh/h

Segment

Standard Analysis Results

0

0

200

Av. Queue veh

43

39

55

Densityveh/mi/ln

7,100

6,200+800

7,000

Capacityveh/h

E7,000Basic 2

E6,200+800Ramp Junction

F6,600Basic 1

LOSInflowveh/h

SegmentResults with Consideration of Queues (1 hr)

F-4

ConceptsTraffic Density and Speed in Queues

V = S·DS = V/D

ConceptsDemand Prediction (veh/h)

O1 =600

O =5,000

O2 =400

5 % D = ?

D1 = ?

D1 = 0.05x(5,000+600+400) = 300

D = (1-0.05)x (5,000+600+400) = 5,700

F-5

ConceptsDemand Derived from Measured Volumes (veh/h)

O1 =600

O =5,000

O2 =400

D = 5,415

D1 = 285

ΣO = 5,000+600+400 =6,000 veh/hΣD = 5,415+285 = 5,700 veh/hΣO > ΣD What may the cause be?

ConceptsDemand Derived from Measured Volume (veh/h)

O1 =600

O =5,000

O2 =400

D = 5,415

D1 = 285

ΣO/ΣD = 6,000/5,700 = 1.053All the exit volumes have to be multiplied with 1.053 to restore demand balanceThe true exit demands are:D = 5,415 x 1.053 = 5,700 veh/hD1 = 285 x 1.053 = 300 veh/hCan ΣO < ΣD?

F-6

ConceptsFreeway Sections and Segments

Max. 9-12 mi

ConceptsTime-Space Domain

Tim

e Period (several hours, all rows)Time Interval (15 minutes, single row)Time Step (1 minute, calculations for over-saturated conditions)

F-7

ConceptsInitial and Boundary Conditions

Demand-to-capacity RatiosInitialConditions

ResidualConditions

UpstreamBoundaryConditions

DownstreamBoundaryConditions

ConceptsInput Data

F-8

ConceptsMeasures of Effectiveness

Average density (veh/mi/ln)Level of ServiceAverage speed (mi/h)Average travel time (min)Average delay (min)Occupancy (%)Queue length (mi)Vehicle-miles of travel (veh·mi)Vehicle-hours of travel (veh·hr)Vehicle-hours of delay (veh·hr)

Methodology

F-9

MethodologyGeometric Data

Acc./Dec. lanes are 328 ft long,Time interval is 15 min.

MethodologyDemand Data

F-10

MethodologySpace Domain

MethodologyDemand Adjustment

Time Interval 1

ΣO = 4796+756+1456+648 = 7656 veh/h

ΣD = 656+560+6440 = 7656 veh/h

ΣO = ΣD

Demand is balanced in all the intervals.

No demand adjustment is needed.

F-11

MethodologyDemand-Capacity Ratios

All the segments areunder-saturated

MethodologySegment Speeds

F-12

MethodologySegment Densities and LOS

MethodologyFacility MOEs

F-13

MethodologyDemand Data

Let us increase the demand by 6%

MethodologyDemand-Capacity Ratios

Some segments areover-saturated ininterval 3

F-14

MethodologyVolume-Capacity Ratios

MethodologyEffect of Overflow

F-15

MethodologyQueue Lengths

Queue on the rampNo queue on the freeway

No congestion

Congestion

MethodologySegment Densities and LOS

F-16

MethodologyFacility MOEs

HCS


F-17

Exercise – Reconstructed BormanGeometry

Exercise – Reconstructed BormanGeometry

F-18

Exercise – Reconstructed BormanGeometry Summary

Exercise – Reconstructed BormanPredicted Hourly Traffic

F-19

Exercise – Reconstructed BormanTasks

1. On the post construction westbound roadway of I-80/94, identify all the section/segments as required for freeway facility analyses. Limit the analysis to the freeway section between the I-65 South connector ramp and the Grant Street interchange. In Table 1, write the consecutive number of each identified segment, type of segment (basic, ramp, weave), the stations of its beginning and its end.

2. Using the freeway facility module, input the freeway segments corresponding to the designed freeway geometry. Analyze the facility for the 2024 morning peak traffic. Write the results in Table 1.

3. Increase the 2024 traffic volumes by 25% and analyze the facility again. Write the results in Table 1. Note the differences in the results.

ExerciseTable 1

Table 1: Results of the freeway exercise (freeway facility analysis for post construction geometry)

Seg. #

Segment Name/TypeStations 2024 Traffic 2024 Traffic Increased by 25%

Start End Density

(pc/km/ln)Speed(km/h)

LOS Density(pc/km/ln)

Speed(km/h)

LOS

F-20

END

of freeway facilities

B-1

Chapter 23 Basic Freeway Segments



Outline


B-2

Concepts

ConceptsBasic Freeway Segments

Full access control dividedUrban and ruralNo influence of ramps and weaving

B-3


1500 ft 1500 ft 1500 ft 1500 ft

If > 2,500 ft then twoseparate ramp junctions


B-4

ConceptsInput Data

ConceptsBase Conditions

Minimum lane widths of 12 ft;Minimum outside lateral clearance of 6 ft;Minimum median lateral clearance of 2 ft;Passenger cars only;Five or more lanes for one direction (in urban areas only);Interchange spacing at 2 mi or greater;Level terrain, with grades no greater than 2 percent; andRegular users.

B-5

ConceptsLimitations

High-occupancy vehicle (HOV) lanes, truck lanes, and climbing lanes;Extended bridge and tunnel segments;Segments near a toll plaza;Facilities with free-flow speeds below 55 mi/h or in excess of 75 mi/h;Demand conditions in excess of capacity;The influence of downstream blockages or queuing on a segment;Special enforcement or control means.

ConceptsSpeed-flow Curves

V=1,000 pc/h/lnS = 60 mi/hD = 16.7 pc/mi/ln

vp=2,250 pc/h/ln

S = 50 mi/h

D = 45 pc/mi/ln

B-6

ConceptsFree-flow Speed

Base FreeFlow Speed

Effect ofLane Width

Effect of Lateral Clearance

Number of Lanes Effect

Effect of Interchange Density

Free FlowSpeed

ConceptsLevel of Service

LOS F

LOS A

LOS E

B-7

ConceptsFlow Rate

Flow Rate

PeakHourFactor

Numberof Lanes


HourlyVolume

Effect of Heavy Vehicles



Methodology

B-8

MethodologyInput

Urban freeway is designed,BFFS of 70 mi/h,12-ft lane width, 6-ft lateral clearance,1.50 interchanges per mile,4,000 veh/h (one direction), 0.85 PHF,Level terrain, 15 percent trucks, 3 percent RVs, Commuter traffic, fp = 1.00,How many lanes for LOS D?

MethodologyFlow Rate for 4-Lane Freeway

Level terrain, 15 percent trucks, 3 percent RVs,

B-9

4,000 veh/h (one direction), 0.85 PHF,fHV = 0.925Commuter traffic, fp = 1.00.


The flow rate is higher than the capacity for 4-lanefreeways (c = 2,400 pc/h/ln)

MethodologyFree Flow Speed for 6-lane Freeway

Urban freeway is designed,BFFS of 70 mi/h,12-ft lane width, 6-ft lateral clearance,1.50 interchanges per mile.

B-10

MethodologyFree Flow Speed for 6-lane Freeway

Urban freeway is designed,BFFS of 70 mi/h,12-ft lane width, 6-ft lateral clearance,1.50 interchanges per mile.

4,000 veh/h (one direction), 0.85 PHF,fHV = 0.925Commuter traffic, fp = 1.00.


B-11

Methodology LOS

FFS = 62.0-mi/hvp = 1,696 pc/h/ln

S = 62.0 mi/hD = vp/SD = 1,696/62.0D = 27.4 pc/mi/ln

D

HCS


B-12

Exercise - Borman Expressway

1. Distribute among students

2. Introduce

Hohm

anAve underpass

IL / INState Line

Little Calum

et River

Old L & N

RR

Harrison Ave underpass

US 41 / C

alumet Ave

Interchange

Colum

bia Ave overpass

Northcote

Ave underpass

Old C

& O R

R M

ulti-use Pathunderpass

US 41 / Indianapolis Blvd

Interchange

CSX R

R underpass

Kennedy AveInterchange

SR 912 / C

line AveInterchange

SR 912 / C

line AveInterchange

N &W

/ EJ & E RR

underpass

Colfax St. overpass

Burr StInterchange

Clark St. overpass

Chase St. overpass

Harrison St. overpass

Georgia St. overpass

Little Calum

et River

Grant Street

Interchange

SR 53 / Broadw

ay StInterchange


Little Calum

et River

Martin Luther King D

rive overpass

I-65 Interchange

Borman / I-65 Connector Ramps

Colorado Street

overpass

Deep R

iver

Central AveInterchange

Clay Street underpass

Borman Expressway

B-13

Hohm

anAve underpass

IL / INState Line

Little Calum

et River

Old L & N

RR


US 41 / C

alumet Ave

Interchange

Colum

bia Ave overpass

Northcote

Ave underpass

Old C

& O R

R M



Interchange

CSX R

R underpass


SR 912 / C

line AveInterchange

SR 912 / C

line AveInterchange

N &W

/ EJ & E RR

underpass

Colfax St. overpass

Burr StInterchange

Clark St. overpass

Chase St. overpass



Little Calum

et River

Grant Street

Interchange

SR 53 / Broadw

ay StInterchange


Little Calum

et River


rive overpass

I-65 Interchange


Colorado Street

overpass

Deep R

iver



Borman Expressway--Interchange Work

No Modification--Already Done Presently under Construction

Minor Modification Proposed Major Modification (Reconfiguration) Proposed

Hohm

anAve underpass

IL / INState Line

Little Calum

et River

Old L & N

RR


US 41 / C

alumet Ave

Interchange

Colum

bia Ave overpass

Northcote

Ave underpass

Old C

& O R

R M



Interchange

CSX R

R underpass


SR 912 / C

line AveInterchange

SR 912 / C

line AveInterchange

N &W

/ EJ & E RR

underpass

Colfax St. overpass

Burr StInterchange

Clark St. overpass

Chase St. overpass



Little Calum

et River

Grant Street

Interchange

SR 53 / Broadw

ay StInterchange


Little Calum

et River


rive overpass

I-65 Interchange


Colorado Street

overpass

Deep R

iver



Borman Expressway

B-14

Exercise - Borman ExpresswaySection Studied

I-65

On

Ram

p

Bro

adw

ay In

terc

hang

e

Gra

nt In

terc

hang

e

Exercise - Borman ExpresswayI-65 On Ramp

250-m acceleration lane

B-15

Exercise - Borman ExpresswayBroadway Off Ramp

420-m deceleration lane

Exercise - Borman ExpresswayBroadway Weave

145-m weaving segment

B-16

Exercise - Borman ExpresswayGrant Interchange

Similar toBroadway Interchange

Exercise - Borman ExpresswayPre-construction Geometry Summary

B-17

Exercise - Borman Expressway2006 -2024 Traffic

Exercise - Borman ExpresswayTasks

1. On the pre-construction westbound roadway between the I-65 South connector ramp and the Grant Street interchange, identify all the basic freeway segments, ramp junction segments, and weaving segments. Use the provided materials. In provided Table 2, write the consecutive number of each identified segment, type of segment (basic, ramp, weave), the stations of its beginning and its end. The LOS and other basic traffic conditions will be determined later.

2. Determine the level of service of the first basic segment for the pre construction geometry and for the 2006 and 2024 morning peak traffic. Write the obtained results in Table 2. Save the HCS file on the provided CD media for future reference.

3. Repeat the same analysis for as many basic segments as time permits.

B-18

Seg. # Segment Name/Type

Stations 2006 Traffic 2024 Traffic

Start End Density(pc/km/ln)

Speed(km/h) LOS

HCS File

Density(pc/km/ln)

Speed(km/h) LOS

HCS File

Exercise - Borman ExpresswayTable with Results

Table 2: Results of the freeway exercise (individual segments analysis for pre construction geometry)

Task 1

Results

END

of basic freeway segments

W-1

Chapter 24 Freeway Weaving



Outline


W-2

ConceptsWeave Formation

ConceptsWeave Formation

Non-weaving Flow A-C

Non-weaving Flow B-D

Weaving Flow B-C

Weaving Flow A-D

W-3

ConceptsWeave Type A

ConceptsWeave Type B

(c)

W-4

ConceptsWeave Type C

ConceptsWeaving Length

W-5

ConceptsWeaving Width

Nw(max)=

Nw(max)=

Nw(max)=

Nw = numberof lanes requiredfor weaving

ConceptsFlow Rate

Flow Rate

PeakHourFactor


HourlyVolume

Effect of Heavy Vehicles on Grades



Proportion of Trucks andBuses Proportion of

RecreationalVehicles

W-6

ConceptsUnconstrained and Constrained Operation

Nw≤ Nw(max) Unconstrained operation• speed of weaving vehicles is only slightly lower than non-weaving vehicles• non-weaving vehicles use the lanes with weaving vehicles• traffic across lanes is more less balanced

Nw > Nw(max) Constrained operation • weaving vehicles move much slower than non-weaving vehicles• non-weaving vehicles try to avoid the lanes with weaving vehicles

ConceptsSpeed of Weaving and Non-weaving Traffic

Freeway Free-flow Speed

Weaving Intensity; depends on whether the operation is constrained or not, total volume, weaving ratio, and weave length

Speed of Weaving or Non-weaving traffic

W-7

ConceptsAverage Speed and Density

Total FlowAverage Speed

Weaving Flow

Non-weaving Flow

Non-weaving Speed

Weaving Speed

Total Flow

Number of Lanes

Average Speed

Average Density


W-8

ConceptsWeaving Segment Capacity

Capacity occurs at any combination of weaving and non-weaving flows that produce average density equal 43 veh/mi/ln.

Capacity can be determined by:

1. Trials and errors

2. Using programmed spreadsheets

3. Using tables provided by the HCM

Methodology

W-9

MethodologyInput

PHF = 0.91,Level terrain,Drivers are regular commuters,FFS = 65 mi/h for freeway, 10 percent trucks, LOS ?

(veh/h)

Level terrain,10 percent trucks.

MethodologyFlow Rates

W-10

MethodologyWeave Type

MethodologyCritical Variables

2,095

7991,197

1,497pc/h

W-11

MethodologyUnconstrained Speeds

MethodologyConstrained Operation Check

W-12

MethodologyAverage Speed and Density

MethodologyLevel of Service

D = 27.3 pc/mi/ln

W-13

HCS


Exercise1. Determine the level of service of the first

weaving segment for the pre construction geometry (2002) for the 2006 and 2024 morning peak traffic. Write the obtained results in Table 2. Save the HCS file on the provided CD media for future reference.

2. Repeat the same analysis for as many weaving segments as time permits.

W-14

END

of freeway weaving

R-1

Chapter 25 Ramps and Ramp Junctions



Outline


R-2

ConceptsInfluence Areas

ConceptsCapacity Factors

Lane widths, lateral clearances, terrain, driver population, and the presence of heavy vehicles Length of acceleration/deceleration lane Ramp free-flow speedLane distribution of upstream traffic

R-3

ConceptsV12 Volume

ConceptsV12 Volume for On-Ramp Junctions

Adjacent Upstream Ramp

Lup < LEQ then use Equation 2Otherwise, use Equation 1

Adjacent Downstream Ramp

Ldown < LEQ then use Equation 3Otherwise, use Equation 1

Lup Ldown

Analyzed Ramp

R-4

ConceptsV12 Volume for Off-Ramp Junctions

Lup Ldown

Analyzed Ramp

Adjacent Downstream Ramp

Ldown < LEQ then use Equation 7Otherwise, use Equation 5

Lup < LEQ then use Equation 6Otherwise, use Equation 5

Adjacent Upstream Ramp

ConceptsCapacity

R-5

ConceptsCapacity

ConceptsInputs

R-6

ConceptsAcceleration/ Deceleration

Length

Methodology

R-7

MethodologyRoadway and Traffic

ConditionsIsolated location, PHF = 0.90,Drivers are regular commuters,Adequate lateral clearances,0 percent RVs,

MethodologyFlow Rates

Isolated location, PHF = 0.90,Drivers are regular commuters,Adequate lateral clearances,0 percent RVs,

R-8

MethodologyVolume V12

MethodologyCapacity Check

Two lanesFFS = 60 mi/h

R-9


C1 = 4600 pc/hC2 = 4600 pc/hV12 = 2918 pc/h, VR = 626 pc/h

< C1 = 4600

VR12 = VR+V12 = 626+2918 = 3544 < C2 = 4600

MethodologyDensity

V12 = 2918 pc/h VR = 626 pc/hLA = 750 ft

R-10

MethodologyLOS

Dr = 28.1 pc/mi/lane

MethodologySpeed

R-11

MethodologyVolume V12


R-12


MethodologyDensity

R-13

MethodologySpeed

MethodologySpecial Cases

Two-Lane Ramps

Lane Additions/Drops

Major Merge/Diverge Areas

Ramps on Ten-Lane Freeway

Left-Hand Ramps

Effects of Ramp Control at On-Ramps

R-14

MethodologyTwo-Lane On-Ramps

V12=VF·PFM

MethodologyTwo-Lane Off-Ramps

Adjusted PDF factor to calculate V12

Adjusted deceleration lane LD

R-15

MethodologyLane Additions and Drops

Consider two basic freeway segments

MethodologyMajor Merges

Consider three basic freeway segments

R-16

MethodologyMajor Diverges

1. Consider three basic freeway segments

2. In addition, check density upstream of the fork

D = 0.0109·VF/N (use Ex. 25-4 to determine LOS)

MethodologyOn-ramps on Ten-lane Freeways

1. Calculate volume in the fifth lane V5

2. Subtract V5 from VF

3. Proceed as for the eight-lane freeway

R-17

MethodologyRamps on Ten-lane Freeways

1. Calculate volume in the fifth lane V5

2. Subtract V5 from VF

3. Proceed as for the eight-lane freeway

MethodologyLeft-hand Ramps

1. Calculate volume V12 as for a right-hand ramp

2. For four-lane freeways use V12

3. For six- and eight-lane freeways, convert V12 to V23 or to V34, respectively

4. Proceed as for the right-hand ramp

Off-rampOn-ramp

1.20

1.12

1.00

1.10Eight-lane

1.05Six-lane

1.00Four-lane

Conversion FactorFreeway

R-18

MethodologyEffect of Ramp Metering

Use the ramp flow rate enforced by metering instead of the capacity governed by the ramp geometry

HCS


R-19

Exercise1. Determine the level of service of the first

ramp junction segment for the before construction geometry and for the post construction 2006 and 2024 morning peak traffic. Write the obtained results in Table 2.Save the HCS file on the provided CD media for future reference.

2. Repeat the same analysis for as many ramp junction segments as time permits.

END

of ramp junctions

T-1

Chapter 26 Interchange Ramp Terminals



Outline

Concepts

T-2

ConceptsContents

Types of freeway-highway interchangesTraffic issues at signalized diamond interchangesLevel of ServiceAppendix A Signal timing considerations for diamond interchangesAppendix B Comparing alternative interchanges

ConceptsTypes of Interchanges

T-3

ConceptsTraffic Operations at Diamond Interchanges

ConceptsTraffic Operations at Diamond Interchanges

1. Upstream intersection blocked by the downstream queue

2. Aggressive lane changing between intersections

3. Green at the downstream intersections not fully utilized

4. Effective traffic control difficult

T-4


1. Both the intersections are considered together as a point facility

2. Each lane groups is evaluated separately

3. LOS criteria for signalized intersections are used

ConceptsPhasing Consideration for Diamond Interchanges

T-5

ConceptsPhasing Consideration for Diamond Interchanges

ConceptsOffset Consideration for Diamond Interchanges

Offset equal travel timebetween the stop-bars

Adjustment for number of vehicles that arriveduring red signal

Adjustment for number of vehicles that fillthe space between the intersections

T-6

ConceptsDiamond vs. SPUI

• SPUI – a possible solution


T-7

65 Three Phases


END

of interchange ramp terminals

HCM 2000 Course


Laboratory Assignment


Teaching Assistant

Tim Wells


June 19-21, 2006

A-1

A-2

Multilane Highway – US 52

Existing Conditions Future needs of widening of the U.S. Highway 52 south of Lafayette, Indiana, are to be studied. The segment 2.8 miles long in Tippecanoe County between CR 350 S and CR 550 S is considered in this exercise. Figure 1 shows the location of the segment while Figures 2 through 4 show the existing geometry of this highway segment. Geometry and Pavement A site study has revealed that the following characteristics of the highway segment:

- Full-depth asphalt pavement with painted striping - Two 12-foot travel lanes - Divided cross-section with 6 feet of left-side clearance - 2-foot right shoulders - Ten residential and commercial access points along highway section in the

Southbound direction - Slightly rolling vertical alignment without pronounced grades

Traffic The AADT is 10,780 vehicles /day for the year 2003. Five percent trucks and one percent recreational vehicles may be assumed. Because of the proximity of I-65 three miles to the east, the traffic on U.S. 52 almost has local range. Twelve percent of AADT is observed during the typical afternoon rush hour (design hour) with 60 percent of traffic in the southbound direction. The peak hour factor (PHF) of 0.92 may be assumed. The speed limit is 55 mph.

Figure 1. Map of Study Section

A-3

Figure 2. U.S. 52 at Tippecanoe County Road 550 S looking southward.

Figure 3. U.S. 52 near Tippecanoe County Road 450 S, near the midpoint of the study section.

A-4

Figure 4. Typical business entrance along U.S. 52 near the north end of the section at Tippecanoe County Road 350 S.

Assignment (Multilane Highways) Much of the land surrounding the US 52 near Lafayette is zoned for industrial or commercial use in anticipation of expansion of the city. Because of this, traffic growth along the section is anticipated to occur at an accelerated rate of 3% per year.

1. Please check the present traffic conditions (2006) in the peak direction during the afternoon rush hour.

2. Determine in which year the US52 near Lafayette may require upgrading to

accommodate increased traffic. LOS C is the minimum requirement.

A-5

HCM Freeway Exercises

Introduction The Indiana Department of Transportation has been working to upgrade sections of the Borman Expressway (I-80/I-94) near Gary, Indiana. The improvements to the highway include reconfiguration of the interchanges and addition of an extra travel lane in each direction. This exercise includes the freeway section between the Grant Street interchange and the I-65 South connector ramps. The Grant Street and Broadway cloverleaf interchanges in this 3.9 km stretch have not been upgraded since their original construction in the mid 1960’s. At the start of reconstruction the highway was expected to be complete by 2006, with a target design year of 2024. Assume that the construction has been completed. These notes give information necessary for evaluating traffic conditions in 2006 and future traffic conditions in 2024 for the before construction existing and designed geometry excerpted from the INDOT Engineer’s Report: I-80/94 Borman Expressway – Appendices B and C, Volume 3, year 2000. The information is provided in two sections: Before Construction Geometry and Traffic Data and Designed Geometry and Traffic Data. First, the assignment is described for each teaching module of the HCM course pertaining to the freeway chapters of the Highway Capacity Manual. Then, the two sections with traffic and geometry follow.

Assignment for Freeways Problem for Freeway Facilities On the post construction westbound roadway of I-80/94, identify all the section/segments as required for freeway facility analyses. Limit the analysis to the freeway section between the I-65 South connector ramp and the Grant Street interchange. Use the drawings of the geometry provided in the further part of these notes. In Table 1, write the consecutive number of each identified segment, type of segment (basic, ramp, weave), the stations of its beginning and its end, and the LOS and other basic traffic conditions as determined later in the course of the lab activities. Using the freeway facility module, input the freeway segments corresponding to the designed freeway geometry. Analyze the facility for the 2024 morning peak traffic. Examine the results. Increase the 2024 traffic volumes by 25% and analyze the facility again. Note the differences in the results.

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Dividing Freeway Facility into Segments On the before construction westbound roadway between the I-65 South connector ramp and the Grant Street interchange, identify all the basic freeway segments, ramp junction segments, and weaving segments. Use the provided drawings. In Table 2 on the next page, write the consecutive number of each identify segment, type of segment (basic, ramp, weave), the stations of its beginning and its end, and the LOS and other basic traffic conditions as determined later in the course of the lab activities. Problem for Basic Freeway Segments Determine the level of service of the first basic segment for the before construction geometry and for the 2006 and 2024 morning peak traffic using the HCS 2000. Write the obtained results in Table 2. Save the HCS file on the provided CD media for future reference. Repeat the same analysis for as many basic segments as time permits. Problem for Ramp Junctions Determine the level of service of the first ramp junction segment for the before construction geometry and for the 2006 and 2024 morning peak traffic using the HCS 2000. Write the obtained results in Table 2. Save the HCS file on the provided CD media for future reference. Repeat the same analysis for as many ramp junction segments as time permits. Problem for Freeway Weaving Determine the level of service of the first weaving segment for the before construction geometry and for the 2006 and 2024 morning peak traffic using the HCS 2000. Write the obtained results in Table 2. Save the HCS file on the provided CD media for future reference. Repeat the same analysis for as many weaving segments as time permits.

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Table 1: Results of the freeway exercise (freeway facility analysis for after construction geometry)

Stations 2024 Traffic 2024 Traffic Increased by 25%

Seg. #

Segment Name/Type

Start End Density (pc/km/ln)

Speed (km/h)

LOS Density (pc/km/ln)

Speed (km/h)

LOS

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Table 2: Results of the freeway exercise (individual segments analysis for before construction geometry)

Stations 2006 Traffic 2024 Traffic Seg. #

Segment Name/Type Start End Density

(pc/km/ln) Speed (km/h)

LOS HCS File

Density (pc/km/ln)

Speed (km/h)

LOS HCS File

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Before Construction Geometry and Traffic Data (Freeway)

Geometric Data A schematic drawing of the before construction freeway westbound roadway is shown in Figure 5. The existing freeway has three 3.6 m travel lanes, a 3.1 m right shoulder, and a 3.6 m left shoulder. The additional lane in the weaving areas is 3.6 m. The terrain is level.

Figure 5 Before Construction geometry of the westbound roadway

Traffic Data Traffic diagrams for the before construction geometry are included in this section (Figures 6 and 7). The before construction speed limit was 55 mi/h. Speed on the loop ramps can be assumed 40 km/h, and speed on direct ramps 60 km/h. The peak hour factor (PHF) is assumed to be 1.00. A significant portion of the freeway flow is long-distance traffic. The freeway is a major server of commuter traffic into the Chicago metropolitan area.

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Figure 6 Design hourly volumes for before construction geometry

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Figure 7 Design hourly volumes for 2006 and 2024 years, AM.

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Designed Geometry and Traffic Data

Geometric Data Figure 8 presents post construction geometry of the Grant Interchange. The Broadway Interchanges has been transformed in a similar way. The additional lane is continuous between interchanges. After adding another lane in the median, the cross-section (see Figure 9) includes 10 3.6-m traveled lanes between interchanges and eight 3.6 m traveled lanes within the interchanges. The outside and median shoulders are 3.6 m. The median is divided with a Jersey barrier placed in the middle. The terrain is level. A summary of the post construction geometry for the entire studied facility in the westbound direction is shown in Figure 10.

Figure 8 Post construction geometry of the Grant Interchange.

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Figure 9 Cross-sections of new Borman Expressway

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Figure 10 Schematic drawing of the post construction geometry Traffic Data The traffic data for the post construction geometry is included in this section (Figure 11). The freeway will have a speed limit of 65-mi/h. The ramp geometry indicates free flow speed of 40 km/h for loop ramps and 60 km/h for direct ramps as a reasonable choice for traffic analysis. The peak hour factor (PHF) is assumed to be 1.00 for all situations. A significant portion of the freeway flow is long-distance traffic. The freeway is a major server of commuter traffic into the Chicago metropolitan area.

Figure 11 Predicted AM design volumes for 2006 and 2024.

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Solutions of Laboratory Assignment


Teaching Assistant

Tim Wells


June 19-21, 2006

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Multilane Highway – US 52

INPUT Present Conditions Future needs of widening of the U.S. Highway 52 north of Lafayette, Indiana, are to be studied. The segment 2.8 miles long in Tippecanoe County between CR 350 S and CR 550 S is considered in this exercise. Figures 1 shows the location of the segment while Figures 2 through 4 show the present geometry of this highway segment. Geometry and Pavement A site study has revealed that the following characteristics of the highway segment:

- Full-depth asphalt pavement with painted striping - Two 12-foot travel lanes - Divided cross-section with 6 feet of left-side clearance - 2-foot right shoulders - Ten residential and commercial access points along highway section in

the Southbound direction - Slightly rolling vertical alignment without pronounced grades

Traffic An AADT map indicates 10,780 veh/day in 2003. Five percent trucks and one percent recreational vehicles may be assumed. Because of the proximity of I-65 three miles to the east, the traffic on U.S. 52 almost has local range. Twelve percent of AADT is observed during the typical afternoon rush hour (design hour) with 60 percent of traffic in the southbound direction. The peak hour factor (PHF) of 0.92 may be assumed. Assume the current speed limit along the highway is 55 mph. Assignment Much of the land surrounding the US 52 near Lafayette is zoned for industrial or commercial use in anticipation of expansion of the city. Because of this, traffic growth along the section is anticipated to occur at an accelerated rate of 3% per year.

1. Please check the present traffic conditions in the peak direction during the afternoon rush hour.

2. Determine in which year the analyzed US 52 segment would require

upgrading to accommodate increased traffic. LOS C is the minimum requirement.

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Problem Solutions for Multilane Highways Comments on Problem 1: Access points per mile = 10 access points / 2.8 miles = 3.6 points per mile Volume in 2006 = 10,780 x (1.03)2006-2003 = 11,780 veh/day Volume = 11,780 x 0.12 x 0.6 (peak direction) = 850 veh/h See Figure 1: Multi-Lane Problem #1 (Solution) Comments on Problem 2: By the trial-and-error method, the critical volume for LOS C has been found, VC = 2694 veh/h. Volume in 2045 will be 10,780 x (1.03)(2045 – 2004) x 0.12 x 0.6 = 2686 veh/h. This is the predicted last year when the road segment will operate at LOS C. See Figure 2: Multi-Lane Problem #2 (check of highest volume that still provides LOS C) and Figure 3: Multi-Lane Problem #2 (verify LOS D for 2695 vph)

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HCS2000: Multilane Highways Release 4.1c Phone: Fax: E-mail: ___________________________OPERATIONAL ANALYSIS________________________________ Analyst: Solution Agency/Co: HCM_Short_Course_2006 Date: 6/18/2006 Analsis Period: PM peak Highway: US 52 (Tippecanoe County) From/To: 350 South to 550 South Jurisdiction: INDOT Analysis Year: 2006 Project ID: 2006 Existing Conditions _______________________________FREE-FLOW SPEED_________________________________ Direction 1 2 Lane width 12.0 ft 12.0 ft Lateral clearance: Right edge 2.0 ft 6.0 ft Left edge 6.0 ft 6.0 ft Total lateral clearance 8.0 ft 12.0 ft Access points per mile 4 0 Median type Divided Free-flow speed: Base Measured FFS or BFFS 60.0 mph 60.0 mph Lane width adjustment, FLW 0.0 mph 0.0 mph Lateral clearance adjustment, FLC 0.9 mph 0.0 mph Median type adjustment, FM 0.0 mph 0.0 mph Access points adjustment, FA 1.0 mph 0.0 mph Free-flow speed 58.1 mph 60.0 mph ____________________________________VOLUME_____________________________________ Direction 1 2 Volume, V 850 vph 0 vph Peak-hour factor, PHF 0.92 0.90 Peak 15-minute volume, v15 231 Trucks and buses 5 % 0 % Recreational vehicles 1 % 0 % Terrain type Rolling Level Grade 0.00 % 0.00 % Segment length 0.00 mi 0.00 mi Number of lanes 2 2 Driver population adjustment, fP 1.00 1.00 Trucks and buses PCE, ET 1.5* 1.5 Recreational vehicles PCE, ER 1.2* 1.2 Heavy vehicle adjustment, fHV 0.974 1.000 Flow rate, vp 474 pcphpl pcphpl ____________________________________RESULTS____________________________________ Direction 1 2 Flow rate, vp 474 pcphpl pcphpl Free-flow speed, FFS 58.1 mph 60.0 mph Avg. passenger-car travel speed, S 58.1 mph mph Level of service, LOS A Density, D 8.2 pc/mi/ln pc/mi/ln Overall results are not computed when free-flow speed is less than 45 mph. Figure 1: Multi-Lane Problem #1 (Solution)

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HCS2000: Multilane Highways Release 4.1c Phone: Fax: E-mail: ___________________________OPERATIONAL ANALYSIS________________________________ Analyst: Solution Agency/Co: HCM_Short_Course_2006 Date: 6/18/2006 Analsis Period: PM peak Highway: US 52 (Tippecanoe County) From/To: 350 South to 550 South Jurisdiction: INDOT Analysis Year: 2006 Project ID: check boundary volume for LOS C _______________________________FREE-FLOW SPEED_________________________________ Direction 1 2 Lane width 12.0 ft 12.0 ft Lateral clearance: Right edge 2.0 ft 6.0 ft Left edge 6.0 ft 6.0 ft Total lateral clearance 8.0 ft 12.0 ft Access points per mile 4 0 Median type Divided Free-flow speed: Base Measured FFS or BFFS 60.0 mph 60.0 mph Lane width adjustment, FLW 0.0 mph 0.0 mph Lateral clearance adjustment, FLC 0.9 mph 0.0 mph Median type adjustment, FM 0.0 mph 0.0 mph Access points adjustment, FA 1.0 mph 0.0 mph Free-flow speed 58.1 mph 60.0 mph ____________________________________VOLUME_____________________________________ Direction 1 2 Volume, V 2694 vph 0 vph Peak-hour factor, PHF 0.92 0.90 Peak 15-minute volume, v15 732 Trucks and buses 5 % 0 % Recreational vehicles 1 % 0 % Terrain type Rolling Level Grade 0.00 % 0.00 % Segment length 0.00 mi 0.00 mi Number of lanes 2 2 Driver population adjustment, fP 1.00 1.00 Trucks and buses PCE, ET 1.5* 1.5 Recreational vehicles PCE, ER 1.2* 1.2 Heavy vehicle adjustment, fHV 0.974 1.000 Flow rate, vp 1503 pcphpl pcphpl ____________________________________RESULTS____________________________________ Direction 1 2 Flow rate, vp 1503 pcphpl pcphpl Free-flow speed, FFS 58.1 mph 60.0 mph Avg. passenger-car travel speed, S 57.8 mph mph Level of service, LOS C Density, D 26.0- pc/mi/ln pc/mi/ln Overall results are not computed when free-flow speed is less than 45 mph.

Figure 2: Multi-Lane Problem #2 (check of highest volume that still provides LOS C)

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HCS2000: Multilane Highways Release 4.1c Phone: Fax: E-mail: ___________________________OPERATIONAL ANALYSIS________________________________ Analyst: Solution Agency/Co: HCM_Short_Course_2006 Date: 6/18/2006 Analsis Period: PM peak Highway: US 52 (Tippecanoe County) From/To: 350 South to 550 South Jurisdiction: INDOT Analysis Year: Project ID: check boundary volume for LOS C _______________________________FREE-FLOW SPEED_________________________________ Direction 1 2 Lane width 12.0 ft 12.0 ft Lateral clearance: Right edge 2.0 ft 6.0 ft Left edge 6.0 ft 6.0 ft Total lateral clearance 8.0 ft 12.0 ft Access points per mile 4 0 Median type Divided Free-flow speed: Base Measured FFS or BFFS 60.0 mph 60.0 mph Lane width adjustment, FLW 0.0 mph 0.0 mph Lateral clearance adjustment, FLC 0.9 mph 0.0 mph Median type adjustment, FM 0.0 mph 0.0 mph Access points adjustment, FA 1.0 mph 0.0 mph Free-flow speed 58.1 mph 60.0 mph ____________________________________VOLUME_____________________________________ Direction 1 2 Volume, V 2695 vph 0 vph Peak-hour factor, PHF 0.92 0.90 Peak 15-minute volume, v15 732 Trucks and buses 5 % 0 % Recreational vehicles 1 % 0 % Terrain type Rolling Level Grade 0.00 % 0.00 % Segment length 0.00 mi 0.00 mi Number of lanes 2 2 Driver population adjustment, fP 1.00 1.00 Trucks and buses PCE, ET 1.5* 1.5 Recreational vehicles PCE, ER 1.2* 1.2 Heavy vehicle adjustment, fHV 0.974 1.000 Flow rate, vp 1504 pcphpl pcphpl ____________________________________RESULTS____________________________________ Direction 1 2 Flow rate, vp 1504 pcphpl pcphpl Free-flow speed, FFS 58.1 mph 60.0 mph Avg. passenger-car travel speed, S 57.8 mph mph Level of service, LOS D Density, D 26.0+ pc/mi/ln pc/mi/ln Overall results are not computed when free-flow speed is less than 45 mph. Figure 3: Multi-Lane Problem #2 (verify LOS D for 2695 vph)

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Multilane Highways and Freeways - Purdue University