PLANNING AND PRELIMINARY ENGINEERING GUIDE FOR USING THE HIGHWAY CAPACITY MANUAL NCHRP 7-22 WORKSHOP 1

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PLANNING AND PRELIMINARY ENGINEERING GUIDE FOR USING THE HIGHWAY CAPACITY MANUAL

NCHRP 7-22 WORKSHOP

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AGENDAThe Project (9:00 AM)

Overview of the Guide (9:30 AM)

Case Studies

• Long Range Regional Plan Update (10:30 AM)• Freeway Master Plan (11:30 AM)• Urban Street BRT Project Planning (2:00 PM)• System Performance Monitoring (2:45 PM)

Wrap Up (3:15 PM)

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1. NCHRP 7-22 PROJECT

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NCHRP 7-22

To develop a guide to help planners take advantage of the HCM to improve their results.

Status

• Stakeholder workshops held to identify planning needs and how the HCM might help.

• Initial rough draft guide for stakeholder review (October)• Revised draft guide for panel review in December.• Final guide submitted for publication June 2015

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THE PEOPLE• The Research Team

• Kittelson & Associates - Rick Dowling, Paul Ryus• North Carolina State University - Bastian Schroeder• University of Idaho - Michael Kyte• Stantec – Tom Creasey

• The Panel

The Panel

Dirk Gross (Ohio) (Chair) Tyrone Scorsone (CSI)

Robert Bryson (Milwaukee) Brian Dunn (Oregon )

Jessie Jones (Arkansas) Subrat Mahapatra (Maryland)

Erik Ruehr (VRPA) Andrew Wolfe (SUNY)

Doug McLeod (Florida) Jeremy Raw (FHWA)

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2. OVERVIEW OF GUIDE

09:30

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CONTENTS

1. Part I - How To Use the Guide

A. Long and Short Range Areawide Planning

B. Project Traffic and Environmental Studies

C. Highway Performance Monitoring

2. Part 2 – Procedures

3. Part 3 – Case Studies

A. Long Range Regional Transportation Plan Analysis

B. Freeway Future Conditions Analysis

C. Analysis of BRT Project on Urban Street

D. Roadway System Monitoring

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PART 1- GATEWAY TO THE GUIDE

Areawide Planning Analysis TaskPart 2

Reference

Part 3 Case

StudiesInput to Travel Demand Models - Estimation of highway segment capacities, and free-flow

speedsSection O4 Ex. I.1

Traffic Assignment Module within the Travel Demand Model - Volume-Delay functions for the estimation of congested

speedsSection O5 Ex. 1.2

Post Processing Travel Demand Model Outputs - Obtain more accurate speed estimates for air quality

analysesSection O5 Ex. I.3

- Spotting auto v/c and LOS hot spots (quick screening) Section O5 Ex. I.4- Estimation of delay based on agency policy Section O5 Ex. I.5- Estimation of queuing Section O5 Ex. I.5- Interpretation of results Section O5 Ex. I.6- Travel time reliability analysis Section O5 Ex. 1.7- Estimation of multimodal quality of service for autos, trucks,

transit, bicycles, and pedestriansSection O5

Ex. I.8Ex. 1.9

Corridor Analyses Section O6 -

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Project Impact & Alternatives Analysis TaskPart 2

ReferencePart 3

Case StudiesInput to Travel Demand Models (if used) - Estimation of highway capacities, and free-flow speeds Sections O4 Ex. I.1Traffic Assignment Module within the Demand Model (if used) - Volume-Delay functions for congested speeds Section O5 Ex. 1.2Input to Microsimulation Model (if used) - Estimation of free-flow speeds Section O4 Ex. I.1Microsimulation Model Validation and Error Checking (if used) - Capacity estimates for error checking simulated bottlenecks Section O4 Ex. I.1Project Impact & Alternatives Analyses - Estimating segment speeds for air quality and noise analyses Sections E-H Case Studies 2-3- Estimating auto intersection utilization (v/c) Sections H-K Case Studies 2-3- Estimation of delay Sections H-K Case Studies 2-3- Estimation of queuing Sections H-K Case Studies 2-3- Interpretation of results Sections E-K Case Studies 2-3- Travel time reliability analysis Sections E-H Case Studies 2-3- Estimation of multimodal quality of service for autos, trucks,

transit, bicycles, and pedestriansSections E-H Case Studies 2-3

Corridor Analyses Section O6 -

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Performance Monitoring TaskPart 2

ReferencePart 3

Case Studies

Estimation of monitoring site capacities, and free-flow speeds Sections O4 Ex. IV.1

For Volume Only Monitoring Sites - Estimation of speeds Section O5 Ex. IV.2

For Travel Time Only Monitoring Segments - Estimation of volumes Section O5 Ex. IV.3

Performance Analyses - Quality Assurance/Quality Control Section O5 Ex. IV.4- Auto and Truck VMT Section O5 Ex. IV.5- Auto and Truck VMT by LOS Section O5 Ex. IV.5- Estimation of delay Section O5 Ex. IV.5- Estimation of queuing Section O5 Ex. IV.5- Travel time reliability analysis Section O5 Ex. IV.5

- Estimation of multimodal quality of service for trucks, transit, bicycles, and pedestrians

Section O5 Ex. IV.5

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PART 2 - PROCEDURESA. Default Values

B. Generalized Service Volume Tables

C. Working with Traffic Demand Data

D. Intersection Traffic Control

E. Guidance for Freeways

F. Guidance for Multilane Highways

G. Guidance for Two-Lane Highways

H. Guidance for Urban Streets

I. Guidance for Signalized Intersections

J. Guidance for Stop-Controlled Intersections

K. Guidance for Roundabouts

L. Guidance for Interchange Ramp Terminals

M. Guidance for Off-Street Pathways

N. Guidance for Corridors

O. Guidance for Areas and Systems

Input Data

Facilities

Intersections

Other

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PART 2 – SECTION E:FREEWAY PROCEDURES• E1. Overview

• E2. Computational Tools

• E3. Data Needs

• E4. Estimating Inputs

• Free flow Speed• Capacity

• E5. Performance Measures

• Speed• Level of Service• Queues• Reliability

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FIRST PAGE - INTRO

E. GUIDANCE FOR FREEWAYS

E1. OVERVIEW A freeway is a separated highway with full control of access and two or more lanes in each direction dedicated to the exclusive use of motorized vehicles. Freeways are composed of various uniform segments that may be analyzed to determine capacity and level of service (LOS). Three types of segments are found on freeways:

• Freeway merge and diverge segments: Segments in which two or more traffic streams combine to form a single traffic stream (merge) or a single traffic stream divides to form two or more separate traffic streams (diverge).

• Freeway weaving segments: Segments in which two or more traffic streams traveling in the same general direction cross paths along a significant length of freeway without the aid of traffic control devices (except for guide signs). Weaving segments are formed when a diverge segment closely follows a merge segment or when a one lane off ramp closely follows a one lane on‐ ‐ ‐ ‐ramp and the two are connected by a continuous auxiliary lane.

• Basic freeway segments: All segments that are not merge, diverge, or weaving segments.

The planning method for freeways focuses on facility level analysis and section level analysis. A section is defined as extending from gore point to gore point, avoiding the need to subdivide the section into 1500 foot long merge and diverge areas. A section may combine several HCM segments. For example, a section extending between and on-ramp and an off-ramp may be composed of 3 HCM segments: a merge segment, a basic or weave segment, and a diverge segment. If the individual segment level analysis is desired then the procedures in the HCM are recommended with defaults for certain inputs. For facility and section level analysis, a simplified version of the HCM operations analysis method is presented.

E2. COMPUTATIONAL TOOLS Two general approaches are available for planning analyses of Freeways. These are:

Generalized service volume table. Using a minimum of input data, AADT and number of lanes, the service volume table provides the expected LOS on a freeway facility for a given

Exhibit E-1: Freeway Analysis Approaches

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FREEWAY DATA NEEDS Required to Estimate

Input Data (units) FFS Cap Spd LOS Que Rel Comments/Defaults

Segment design geometry

• • • • • •

Percent heavy vehicles (%)

• • • • •10% (rural), 5% (urban)

Number of directional lanes

• • • • •Must be provided

Peak hour factor (decimal)

• • • • •0.88 (rural), 0.95 (urban)

Driver pop factor (decimal)

• • • • •1.00

Segment length (mi) • • • • Must be provided

Directional demand (veh/h)

• • • •Must be provided

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TYPICAL PROCEDURES

Estimating Free-Flow Speed The most accurate method for estimating segment free-flow speeds is to measure it in the field during low flow (under 800 veh/hr/ln)1. In urban environments, traffic sensors may be available to allow the estimation of free-flow speeds, however for planning applications this is not usually practical. The HCM provides an equation for estimating free-flow speeds based on facility geometry.2

𝑭𝑭𝑺= 𝟕𝟓.𝟒− 𝒇𝑳𝑾− 𝒇𝑳𝑪− 𝟑.𝟐𝟐𝑻𝑹𝑫𝟎.𝟖𝟒

Equation E-1

Where:

- FFS = free-flow speed (mi/h) - fLW = adjustment for lane width (mi/h)

o (0.0 for 12 foot or greater lanes, 1.9 for 11 foot lanes, 6.6 for 10 foot lanes) (see exhibit 11-8, HCM 2010 for details)

- fLC = adjustment for right side lateral clearance (mi/h) o ranges from zero for 6 foot lateral clearance to 3.0 for one foot lateral clearance on a 2

directional lane freeway (see Exhibit 11-9, HCM 2010 for details). - TRD = total ramp density (ramps/mi)

o Number of on and off-ramps in one direction for 3 miles upstream and 3 miles downstream, divided by 6 miles.

An alternate approach is to assume the free-flow speed (the average speed of traffic under low flow conditions) is equal to the posted speed limit plus an adjustment reflecting local driving behavior. Florida adds 5 mi/h to the posted speed limit.

Estimating Section Capacities Free flow speed and percent heavy vehicles are used to calculate section capacity using the following equation:

𝒄𝒊 = ൫𝟐,𝟐𝟎𝟎+ 𝟏𝟎∗ሺ𝐦𝐢𝐧ሺ𝟕𝟎,𝑺𝑭𝑭𝑺ሻ− 𝟓𝟎ሻ൯𝟏 + %𝑯𝑽/𝟏𝟎𝟎 ∗𝑪𝑨𝑭

Equation E-2

Where:

Ci = capacity of section “I” (vph/ln)

1 Adapted from Exhibit 11-3, HCM 2010, accounting for likely peak hour factor and heavy vehicle effects.

2 Souce: equation 11-1, HCM 2010.

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PART 2 – SECTION H:URBAN STREET PROCEDURES• H1. Overview

• H2. Computational Tools

• H3. Data Needs

• H4. Segment Performance

• H5. Intersection Perform.

• H6. Facility Performance

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FIRST PAGE

H. GUIDANCE FOR URBAN STREETS

H1. OVERVIEW Any street or roadway with traffic signals, roundabouts, all-way stops, or two-way stops (interrupting the through traffic movements) that are spaced no farther than 2 mi apart can be evaluated using the HCM methodology for “urban streets.” The street usually is located in a suburban or urban area with frequent driveway access to fronting properties, but that is not a requirement for use of the HCM urban streets analysis method. All streets and roadways meeting the 2-mile criteria are grouped under the broad category of “interrupted flow facilities” and may be evaluated using the procedures described here and in Volume 3 of the 2010 HCM.

There is one caveat to this inclusionary approach for interrupted flow facilities. The HCM methodology focuses on evaluating the speed of through traffic for interrupted flow facilities. However, this is not an appropriate performance measure for evaluating local street performance. Therefore, the methods described in this section and the HCM methodology for uninterrupted flow facilities are not appropriate for the evaluation of local streets.

The planning methods for urban streets focus on facility level analysis, segment level analysis, and intersection level analysis. Facility level performance is estimate by summing the segment (between intersection) and intersection level performance results.

H2. COMPUTATIONAL APPROACH The planning analyses of urban streets proceed in 4 phases. In phase 1, a screening analysis is performed using service volume tables to determine if more detailed planning analysis may be required to identify traffic operations problems on the street. If so, then the next 3 phases of planning analysis are performed: Segment Analysis, Intersection Analysis, and finally, Facility Analysis.

H3. DATA NEEDS Error! Reference source not found. lists the data needed to evaluate the full range of performance measures for planning-level urban street analysis. Individual performance measures

Exhibit H-1: Urban Street Analysis

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URBAN STREET DATA NEEDS

Input Data (units)FFS Cap Spd LOS

MM-LOS

Que RelComments/Defaults

Posted Speed Limit (mi/h) • • • • • required

Intersection Data • • • • • • required

Analysis Period Length (h) • • • • 0.25 h

Segment length (mi) • • • • • required


• • • • •required

Cross-section, bus stops • required

Seasonal demand data • Defaults in appendix

Incident data • Defaults in appendix

Local weather history • Source in appendix

Workzone probability • Defaults in appendix

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TYPICAL PROCEDURE

Speed - Segment The average speed over the segment, inclusive of intersection and midblock bottleneck delays is estimated using the following procedure.

Measure or Estimate Midblock Free Flow Speed The midblock freH-flow speed can be measured in the field or estimated. It is the average spot speed of traffic measured at the mid-point of the segment (see Chapter 30, HCM 2010 for details of measurement method). It can also be estimated using the table and equations provided in Chapter 17, HCM 2010, which are sensitive to signal spacing, median type, curbs and driveway access points. The analyst may also estimate the midblock freH-flow speed by applying an adjustment based on local knowledge of speed limit compliance to the posted speed limit for the segment as follows:

𝐅𝐅𝐒= 𝑷𝑺𝑳+ 𝑨𝑫𝑱 Equation H-1

Where

FFS = the midblock freH-flow speed (mi/h) PSL = the posted speed limit (mi/h) ADJ = Adjustment based on local knowledge (mi/h) – may be positive or negative.

Estimate Intersection delay The intersection control delay is estimated using the appropriate intersection planning method (see Section Error! Reference source not found.) for references to the specific sections in this guide.

Estimate Midblock Delay (if any) Midblock delays are not often present on urban streets; however, If there is a lane drop between intersections (such as might occur at a narrow bridge, or when lanes are added right before an intersection and dropped just after the intersection) then the lane drop creates a midblock bottleneck which may add significant delay when demand is greater than its capacity. The average delay at the midblock bottleneck can be approximated using the equation below. A more precise estimate, taking into account the effects of queue storage, can be made using the method describe in Error! Reference source not found..

Equation H-2

𝑑= 𝑇2𝑚𝑎𝑥ቂ0,ቀ 𝑣𝑐− 1ቁቃ Where

d = average delay due to bottleneck (s/veh). T = analysis period duration (s) (default = 900 secs) v = volume (veh/h)

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PART 2 SECTION I –SIGNALIZED INTERSECTIONS• I1. Overview

• I2. Computational Tools

• I3. Data Needs & Limits

• I4. Performance Estimation

• Screening – Critical Lane Vol.• v/c ratio• Delay• LOS• Queue• Reliability (sensitivity analysis)• Bike/Ped LOS – see Section M

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SIGNALIZED INTERSECTION DATA NEEDS

Required to Estimate

Input Data (units) Cap Del LOS MMLOS Que Rel Comments/Defaults

Number of turn lanes • • • • • n/a required

Other geometry • • • • • Defaults provided

Signal Timing (cycle, g/c) • • • • • Defaults provided

Peak Hour Factor (decimal) • • • • 0.88 (rural), 0.95 (sub.)

Percent heavy vehicles (%) • • • • • 10 (rural), 5 (suburban)

Turning demands (veh/h) • • • • required

Other demands (ped, park) • • • •

Analysis Period Length (h) • • • 0.25 h

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PART 2 SECTION O –AREAWIDE ANALYSES• O1. Overview

• O2. Computational Tools

• O3. Data Needs

• O4. Estimate Demand Model Inputs

• Free-Flow Speed• Capacity

• O5. Performance Measures

• Auto – V/C, Speed, VHT, Delay, LOS, Density, Queue, Reliability.

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DATA NEEDS – AREAWIDE ANALYSIS Required to Estimate Input Data (units)

FFS Cap Spd Que RelComments/Defaults

Facility Type • • • • • Defaults by area and facility type

Segment design geometry

• • • • •Defaults by area and facility type

Terrain type • • • • Must be provided

Percent heavy vehicles (%)

• • • •10% (rural), 5% (urban)

Peak hour factor (decimal)

• • • •0.88 (rural), 0.95 (urban)

Driver pop factor (decimal)

• • • •1.00

Number of directional lanes

• • • •Must be provided

Segment length (mi) • • • Must be provided


• • •Output of Travel Model

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“NO-FAULT” CAPACITY LOOK UP TABLE

Facility Type

Area TypeFree-Flow

Speed (mph)G/C

HCM PC Capacity(veh/ln)

90% PC Capacity(veh/ln)


Freeway

Downtown 55 n/a 2250 2000 1800

Urban 60 n/a 2300 2100 1800

Suburban 65 n/a 2350 2100 1900

Rural 70 n/a 2400 2200 1900

Arterial

Downtown 25 0.45 860 800 700

Urban 35 0.45 860 800 700

Suburban 45 0.41 780 700 600

Rural Multi-Lane 55 n/a 2100 1900 1700

Rural 2-Lane 55 n/a 1600 1400 1300

Collector

Downtown 25 0.41 780 700 600

Urban 30 0.41 780 700 600

Suburban 35 0.37 700 600 600


Rural 2-Lane 45 n/a 1600 1400 1300

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MULTIMODAL LOS DASHBOARD – FOR SYSTEMS

Area Type Facility Type Mode LOS A-C LOS D LOS E LOS F Total

Urban

FreewaysAuto 7% 24% 38% 31% 100%Truck 4% 20% 38% 38% 100%

Non-Freeway

Auto 16% 34% 34% 16% 100%Truck 5% 22% 38% 34% 100%Transit 10% 29% 38% 24% 100%Bicycle 12% 31% 37% 21% 100%Pedestrian 31% 38% 24% 7% 100%

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COMMENTS SO FAR?• Outline and Contents of Guide (Part 1, 2, 3)

• What do you like so far?

• What do you dislike?

• What is missing?

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3. CASE STUDIES

10:30

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CASE STUDY #1 – REGIONAL PLANNING

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CASE 1 - LRTP

Fresno COG 2040 Regional Transportation Plan

- 6,000 square miles

- 1 million population

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OBJECTIVES• Conduct transportation performance and investment

alternatives analysis required to update 2040 LRTP

• Auto, truck, bus, bicycle, and pedestrian analyses to be performed.

• Travel Demand Forecasting Model to be Used

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EXAMPLE PROBLEMS• Example Problems that Develop Demand Model Inputs

• Example I.1 – Estimation of Free-Flow Speeds and Capacities• Example I.2 – HCM Based Volume-Delay Functions

• Example Problems Post Processing Demand Model Outputs

• Example I.3 – Estimating Speeds for Air Quality & Noise Analysis• Example I.4 – Screening for Auto V/C and LOS Hot Spots• Example I.5 – Predicting Queues & Delay• Example I.6 – Interpretation of Results• Example I.7 – Prediction of Reliability• Example I.8 – Transit, bicycle, and pedestrian LOS screening• Example I.9 – Truck LOS screening

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EXAMPLE I.1 – ESTIMATING FREE-FLOW SPEEDS & CAPACITIES• Objective

• To develop lookup table of free-flow speeds and capacities for coding the highway network

• Approach

• Step 1: Identify facility categorization scheme• Step 2: Determine free-flow speeds• Step 3: Determine capacities

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PICKING FACILITY TYPES

Facility Type Area TypeFree-Flow Speed

(mi/h)Capacity(veh/ln)

Freeway

Downtown

Urban

Suburban

Rural

Principal HighwayRural Multi-Lane

Rural Two-Lane

Minor HighwayRural Multi-Lane

Rural Two-Lane

Arterial

Downtown

Urban

Suburban

Collector

Downtown

Urban

Suburban

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FOR FREE-FLOW SPEEDS

• Consult Appropriate HCM Chapter for Procedure, or

• Use Posted Speed Limit + 5 mph

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FOR FREE-FLOW SPEEDS

• Consult Appropriate HCM Chapter for Procedure, or

• Use Posted Speed Limit + 5 mph

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USE “NO-FAULT” CAPACITY TABLE FROM PART 2 - SECTION O

Facility Type

Area TypeFree-Flow

Speed (mph)

G/CHCM PC Capacity(veh/ln)



Freeway

Downtown 55 n/a 2250 2000 1800

Urban 60 n/a 2300 2100 1800

Suburban 65 n/a 2350 2100 1900

Rural 70 n/a 2400 2200 1900

Arterial

Downtown 25 0.45 860 800 700

Urban 35 0.45 860 800 700

Suburban 45 0.41 780 700 600


Rural 2-Lane 55 n/a 1600 1400 1300

Collector

Downtown 25 0.41 780 700 600

Urban 30 0.41 780 700 600

Suburban 35 0.37 700 600 600


Rural 2-Lane 45 n/a 1600 1400 1300

Arterial/Collector assume 1900 ideal sat flow rate

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PICK 80% HCM PC CAPACITY

Facility Type

Area TypeFree-Flow

Speed (mph)

G/CHCM PC Capacity(veh/ln)



Freeway

Downtown 55 n/a 2250 2000 1800

Urban 60 n/a 2300 2100 1800

Suburban 65 n/a 2350 2100 1900

Rural 70 n/a 2400 2200 1900

Arterial

Downtown 25 0.45 860 800 700

Urban 35 0.45 860 800 700

Suburban 45 0.41 780 700 600


Rural 2-Lane 55 n/a 1600 1400 1300

Collector

Downtown 25 0.41 780 700 600

Urban 30 0.41 780 700 600

Suburban 35 0.37 700 600 600


Rural 2-Lane 45 n/a 1600 1400 1300

Arterial/Collector assume 1900 ideal sat flow rate

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EXAMPLE RESULT


(mi/h)Capacity(veh/ln)

Freeway

Downtown 55 1800Urban 60 1800Suburban 65 1900Rural 70 1900

Principal HighwayRural Multi-Lane 55 1700Rural Two-Lane 55 1300

Minor HighwayRural Multi-Lane 45 1500Rural Two-Lane 45 1300

ArterialDowntown 25 700Urban 35 700Suburban 45 600

CollectorDowntown 25 600Urban 30 600Suburban 35 600

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COMMENTS?

Example I.1 – Creation of free-flow speed and capacity look-up tables

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EXAMPLE #I.2 – HCM BASED VOLUME-DELAY FUNCTIONS• Objective

• To select an HCM based volume-delay function for demand model

• Approach

• Step 1: Select volume-delay function type• BPR and Akcelik

• Step 2: Set parameters• Match Speed at Capacity• Compute Akcelik parameter• Compute BPR parameter

• Step 3: Select preferred volume-delay function

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AKCELIK

xLJxxTT 22

0 161125.0

Where:T0 = Free-flow travel timeX = volume/capacity ratioJ = calibration parameterL = length of the link

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BPR

])(*1[*0 BxATT

Where:T0 = Free-flow travel timeX = volume/capacity ratioA = speed at capacity calibration parameterB = rate of travel time increase calibration parameter

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SMOOTH VS ROUGH PIPE

BPR Akcelik

T

Everybodywaits theirturn here.

Free-Flowinghere

Everybodygoes slowentire length

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SPLITTING SMOOTH & ROUGH PIPES

BPR Akcelik

T0.5 Tor T

T or2T

No Problem for DTA, Problem for SUE Models

Problem for DTA, No Problem for SUE Models

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COMPARING SPEEDS

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COMPARING SPEEDS

Speed at Capacity

47

CALIBRATING TO SPEED AT CAPACITY

2

11

fc SSJAkcelik

1c

f

S

SABPR

48

CALIBRATED CURVESFacility Type

Area TypeFree-Flow

Speed (mi/h)

Capacity(veh/ln)

HCM Speed at Capacity

(mi/h)

BPR “a” Parameter

Akcelik “J” Parameter

Freeway

Downtown 55 1800 50.0 0.10 3.31E-06

Urban 60 1800 51.1 0.17 8.43E-06

Suburban 65 1900 52.2 0.25 1.42E-05

Rural 70 1900 53.3 0.31 2.00E-05

Principal Highway

Rural Multi-Lane 55 1700 47.1 0.17 9.30E-06

Rural Two-Lane 55 1300 47.0 0.17 9.58E-06

Minor Highway

Rural Multi-Lane 45 1500 39.6 0.14 9.18E-06

Rural Two-Lane 45 1300 37.0 0.22 2.31E-05

Arterial

Downtown 25 700 23.2 0.08 9.63E-06

Urban 35 700 31.6 0.11 9.45E-06

Suburban 45 600 39.6 0.14 9.18E-06

Collector

Downtown 25 600 23.2 0.08 9.63E-06

Urban 30 600 27.4 0.09 1.00E-05

Suburban 35 600 31.6 0.11 9.45E-06

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ALL GET SAME SPEED AT CAPACITY

Speed at Capacity

50

COMPARING TRAVEL TIMES

51

COMPARING TO HCM

Akcelik vs. HCM

52

COMMENTS?

Example I.2 – Selection of Volume-Delay Functions

53

EXAMPLE I.3 – SPEEDS FOR AIR QUALITY ANALYSIS• Objective:

• to develop a speed-flow equation that accurately reflects queueing delays for post-processing travel demand model outputs for air quality analysis purposes.

• Procedure:

• Step 1: Identify free-flow speeds and capacities• Step 2: Select appropriate Akcelik parameters for links• Step 3: Compute speed for link• Step 4: Interpretation of Results

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POST PROCESSING MODEL SPEEDS

Link ID Type v/c Original Model Speed (mi/h)

A001 Freeway-Urban 1.14 48

A002 Arterial-Urban 0.83 33

A003 Collector-Urban 0.98 26

A004 Freeway-Rural 0.73 67

A005 Highway-Rural 0.44 55

A006 Collector-Rural 0.19 45

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POST PROCESSING MODEL SPEEDS

Link ID Type v/c Original Model Speed (mi/h)

A001 Freeway-Urban 1.14 48

A002 Arterial-Urban 0.83 33

A003 Collector-Urban 0.98 26

A004 Freeway-Rural 0.73 67

A005 Highway-Rural 0.44 55

A006 Collector-Rural 0.19 45

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POST PROCESSING (2)

Link ID

Length (mi)

TypeDemand (veh/h)

Free Speed (mi/h)

80% PC Capacity (veh/h/ln)

Akcelik “J”

Segment Capacity (veh/h)

v/cSpeed (mi/h)

A001 0.85Freeway-

Urban8,220 60 1800 8.40E-06 7,200 1.14 10.0

A002 0.21Arterial-Urban

1,740 35 700 9.34E-06 2,100 0.83 18.7

A003 1.34Collector-

Urban1,170 30 600 9.34E-06 1,200 0.98 26.2

A004 2.50Freeway-

Rural2,790 70 1900 1.99E-05 3,800 0.73 68.7

A005 4.50Highway-

Rural1,490 55 1700 9.34E-06 3,400 0.44 51.5

A006 7.30Collector-

Rural250 45 1300 2.31E-05 1,300 0.19 44.8

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RESULTS – NEW SPEEDS

Link ID Type v/cOriginal Model Speed (mi/h)

Revised Speed (mi/h)

A001 Freeway-Urban 1.14 48 10

A002 Arterial-Urban 0.83 33 19

A003 Collector-Urban 0.98 26 26

A004 Freeway-Rural 0.73 67 69

A005 Highway-Rural 0.44 55 52

A006 Collector-Rural 0.19 45 45

Short vs long segments

58

INTERPRETATION

Link ID Type v/cOriginal Model Speed (mi/h)

Revised Speed (mi/h)

A001 Freeway-Urban 1.14 48 10

A002 Arterial-Urban 0.83 33 19

A003 Collector-Urban 0.98 26 26

A004 Freeway-Rural 0.73 67 69

A005 Highway-Rural 0.44 55 52

A006 Collector-Rural 0.19 45 45

Short vs long segments

Long

(>

1m

ile)

59

COMMENTS?

Example I.3 – Refining speed estimates for air quality analysis.

60

EXAMPLE I.4 – SCREENING FOR AUTO HOT SPOTS• Objective:

• To identify auto volume/capacity ratio and level of service problem spots within the highway system.

• Procedure:

• Step 1: Compute v/c for links• Step 2: Estimate LOS for links

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AUTO V/C LOS TABLE

Facility Type Area TypeFree-Flow

Speed (mi/h)LOS A-C LOS D LOS E

Freeway Rural 65 0.70 0.85 1.00

Freeway Urban 65 0.65 0.85 1.00

Multilane Highway Rural 60 0.65 0.85 1.00

Two Lane Highway Rural N.D. N.D. N.D. N.D.

Arterial Urban 45 0.50 0.90 1.00

Arterial Urban 25-35 0.30 0.80 1.00

62

V/C LOS LOOKUP TABLE

Facility Type Area TypeFree-Flow

Speed (mi/h)LOS A-C LOS D LOS E

Freeway Rural 65 0.70 0.85 1.00

Freeway Urban 65 0.65 0.85 1.00

Multilane Highway Rural 60 0.65 0.85 1.00

Two Lane Highway Rural

Arterial Urban 45 0.50 0.90 1.00

Arterial Urban 25-35 0.30 0.80 1.00

63

EXAMPLE V/C & LOS COMP.

Link ID

Length (mi)

TypeDemand (veh/h)

Free Speed (mi/h)

Segment Capacity (veh/h)

v/c LOS

A001 0.85 Freeway-Urban 8,220 60 7,200 1.14 F

A002 0.21 Arterial-Urban 1,740 35 2,100 0.83 E

A003 1.34 Collector-Urban 1,170 30 1,200 0.98 E

A004 2.50 Freeway-Rural 2,790 70 3,800 0.73 D

A005 4.50 Highway-Rural 1,490 55 3,400 0.44 A-C

A006 7.30 Collector-Rural 250 45 1,300 0.19 A-C

64

COMMENTS?

Example I.4 – V/C and LOS Screening

65

EXAMPLE I.5 – DENSITY, QUEUES, DELAY• Objective:

• To compute and report the density of traffic, hours spent in queues, and hours delay within the highway system.

• Procedure:

• Step 1: Compute Density• Step 2: Compute Vehicle-Hours in Queue• Step 3: Compute Vehicle-Hours of Delay• Step 4: Interpretation of Results

66

DENSITY

𝐷=1.2∗𝑣

𝑁∗𝑆

Where:D = density (pc/mi/ln)v = demand (veh/h)N = number of lanesS = speed (mi/h)PCE = passenger car equivalent

VEH-HRS DELAY

𝑉𝐻𝐷=𝑣∗𝐿𝑆

−𝑣∗ 𝐿𝑆𝑃

Where:VHD = Vehicle-hours delayV = demand (veh/h)L = length of link (mi)S = speed (mi/h)SP = agency’s policy minimum acceptable speed for facility (mi/h)

67

VEH-HRS IN QUEUE• Sum of vehicle-hours spent on links with

• v/c > 1.00 or • speed below the speed at capacity.

• Sum of vehicle-hours delay at intersections

• Average delay at intersection (converted into hours) multiplied by total vehicles entering intersection.

• Exclude free right turn volumes

68

COMMENTS?

Example I.5 – Density, Delay, Queue Calculations

69

EXAMPLE I.6 – REPORTING SYSTEM RESULTS

Link ID

Type L v c FFS CSpd S v/c VMT VHT VHD VHQ

A001Freeway-Urban 0.85 8,220 7,200 60 51.1 10.0 1.14 6,987 700 563 563

A002Arterial-Urban 0.21 1,740 2,100 35 31.6 18.7 0.83 365 20 8 0

A003Collector-Urban 1.34 1,170 1,200 30 27.5 26.2 0.98 1,568 60 3 0

A004Freeway-Rural 2.50 2,790 3,800 70 53.3 68.7 0.73 6,975 102 0 0

A005Highway-Rural 4.50 1,490 3,400 55 47.1 51.5 0.44 6,705 130 0 0

A006Collector-Rural 7.30 250 1,300 45 37.0 44.8 0.19 1,825 41 0 0Total 24,425 1,051 574 563

Inputs Outputs

70

REPORTING SYSTEM LOSArea Type Facility Type Mode LOS A-C LOS D LOS E LOS F Total

Urban

FreewaysAuto 7% 24% 38% 31% 100%

Truck 4% 20% 38% 38% 100%

Non-Freeway

Auto 16% 34% 34% 16% 100%

Truck 5% 22% 38% 34% 100%

Transit 10% 29% 38% 24% 100%

Bicycle 12% 31% 37% 21% 100%

Pedestrian 31% 38% 24% 7% 100%

71

COMMENTS?

Example I.6 – Reporting System Results

72

EXAMPLE I.7 – PREDICTION OF RELIABILITY• Objective:

• To identify auto reliability problem spots and causes within the highway system.

• Procedure:

• Step 1: Compute average annual TTI for links• Step 2: Compute average annual TTI for system• Step 3: Compute 95th percentile annual TTI for system• Step 4: Interpretation of results

73

Travel Time (min)

Num

ber

of T

rips

TRAVEL TIME RELIABILITY

74

Travel Time (min)

Num

ber

of T

rips

Fre

e F

low

Mea

n

95th P

erce

ntile

Trips < 45 mph

CHARACTERIZING RELIABILITY

75

Travel Time (min)

Num

ber

of T

rips

Fre

e F

low

Mea

n

95th P

erce

ntile

THE TTI STATISTIC

𝑇𝑇𝐼95=𝑇𝑇 95

𝑇𝑇𝐹𝑟𝑒𝑒−𝐹𝑙𝑜𝑤

76

Travel Time (min)

Num

ber

of T

rips

Fre

e F

low

Trips < 45 mph

THE PERCENT < 45 MPH

𝑃𝑇 45=𝑇𝑟𝑖𝑝𝑠¿ 45

𝑇𝑜𝑡𝑎𝑙𝑇𝑟𝑖𝑝𝑠

Length/45

77

RELIABILITY PREDICTION• Average Annual TTI

• Recurring Delay Rate

• Incident Delay Rate

Where:TTIm = average annual mean travel time index (unitless)FFS = free-flow speed (mi/h)RDR = Recurring delay rate (h/mi)IDR = Incident Delay Rate (h/miS = peak hour speed (mi/h)N = number of lanes one directionX = peak hour v/c

78

RELIABILITY STATS

• where

• TTI95 = the 95th percentile TTI;

• PT45 = the percent of trips that at speeds less than 45 mph

TTI95 is the ratio of the 95th percentile highest travel time to the free-flow travel time

79

RELIABILITY STATS (2)

Link ID Type VHT(FFS) RDR IDR TTIm VHTm TTI95 VHT<45

A001 Fwy-Urban 116 8.34E-02 6.86E-02 10.13 1,179 1,179

A002 Art-Urban 10 2.49E-02 1.78E-03 1.93 20 20

A003 Coll-Urban 52 4.79E-03 1.48E-02 1.59 83 83

A004 Fwy-Rural 100 2.73E-04 4.91E-04 1.05 105 0

A005 Hiwy-Rural 122 1.23E-03 1.00E-06 1.07 130 0

A006 Coll-Rural 41 8.02E-05 5.12E-11 1.00 41 41

Total or Ave. 441 3.53 1,558 5.63 1,323

57% 43% 85%

80

RELIABILITY GOOD?• Areawide Results

• 95%TTI = 5.63• % Trips < 45 mph = 85%

• Good, Bad, or Ugly?

Level of Service

5% Speed 95% TTI

A >60 mi/h <1.08B 55-60 1.08-1.18C 45-55 1.18-1.44D 35-45 1.44-1.86E 25-35 1.86-2.60F <=25 >= 2.60

Recent TRB Paper

81

COMMENTS?

Example I.7 – Estimating Reliability

82

EXAMPLE I.8 –TRANSIT, BIKE, PED LOS• Objective:

• To screen for multimodal LOS problems in highway system• Procedure:

• Step 1: Select transit, bike, ped service volume tables• Step 2: Screen for transit LOS problems• Step 3: Screen for bicycle LOS problems• Step 4: Screen for pedestrian LOS problems

• Interpretation of Results

• Agency policies vs. LOS

83

TRANSIT LOS

The most important factor = Frequency of Service

Next most important factor = Speed of Transit

Other factors = pedestrian environment, bus stop amenities

Bus Frequency LOS A-C LOS D LOS E LOS F

1 bus/hr N/A N/A >35 mph <30 mph

2 buses/hr >25 mph 10-25 mph 3-10 mph <3 mph

3 buses/hr >11 mph 4-11 mph <4 mph N/A

4 buses/hr >7 mph 2-7 mph <2 mph N/A

84

TRANSIT SERV. VOL. TABLE

Area Type Buses/hSpeed Limit

(mi/h)

Maximum Directional Auto Volume for Target Transit LOS (veh/h/ln)

LOS A-C LOS D LOS E

CBD 6 25 790

890 900Urban 4 35 880

Urban 2 35 10

Suburban 2 45 860

Suburban 1 45 N/A N/A 720

85

BICYCLE & PEDESTRIAN LOS• Depends on:

• Geometric Characteristics• Bike lane, sidewalks, buffer strip, etc.

• Auto Volume• Auto Speed• Percent Trucks

86

BIKE LOS

6' Bike lane

50% Parking

45 mph PSL 35 mph PSL 25 mph PSL

BikeLOS A-C

BikeLOS

D

BikeLOS

E

BikeLOS A-C

BikeLOS

D

BikeLOS

E

BikeLOS A-C

Bike LOS

D

BikeLOS

E

Features

30 160 700 50 250 v/c>1 150 660 v/c>1

✔ 210 v/c>1 v/c>1 330 v/c>1 v/c>1 890 v/c>1 v/c>1

✔ 80 350 v/c>1 120 560 v/c>1 330 v/c>1 v/c>1

✔ ✔ 680 v/c>1 v/c>1 v/c>1 v/c>1 v/c>1 v/c>1 v/c>1 v/c>1

Max Auto Volumes (veh/h/ln)

87

PED LOS6' Bike lane

50% Parkg

6' Buffer

5' Sidewalk

55 mph PSL 25 mph PSL

PedLOS A-

C

PedLOS D

PedLOS E

PedLOS A-

C

PedLOS D

PedLOS E

N/A 10 340 60 390 720

✔ N/A 310 640 360 690 v/c>1

✔ ✔ 340 670 v/c>1 710 850 v/c>1

✔ ✔ 410 740 v/c>1 780 v/c>1 v/c>1

✔ ✔ ✔ ✔ 670 v/c>1 v/c>1 v/c>1 v/c>1 v/c>1

Max Auto Volumes (veh/h/ln)

88

MULTIMODAL LOS ISSUES• What should be transit, bike, ped LOS when agency policy

is not to provide for those services

• Low density areas

• How to estimate multimodal LOS when auto volumes make little or no difference?

• Code basic cross-sectional characteristics into demand model links

• Presence of bike lanes, parking, buffer strip, sidewalk

• Use GIS, color code links by LOS

89

BIKE SYSTEMLOS MAP• These are routes where

agency would like to provide good Bike LOS.

• This is how they rated.

90

COMMENTS?

Example I.8 – Transit, Bike, Ped LOS

91

EXAMPLE I.9 – TRUCK LOS• Objective: To identify truck level of service problem

facilities within the highway system.

• Procedure:

• Step 1: Select truck LOS table• Step 2: Assign links to truck LOS table entries• Step 3: Tally truck LOS results• Step 4: Interpretation of results

92

TRUCK LOS• Depends on :

• Peak hour truck speed (recurring congestion)• Probability of on-time arrival (reliability) • Tolls• Truck friendliness index

• Percent of legal loads and vehicles that can use facility• Number of at-grade railroad crossings

• Goods movement functional class of facility• Inter-regional facility• Primary regional facility• Supporting facility (feeds intermodal terminals)

93

TRUCK TTI LOS LOOKUP

Truck TTI 95% TTI POTA %Ideal Class I Class II

Class III

Freeways and Rural

Highways

FFS = 55-

75 mi/h

1.05 1.18 99% 90% A A A

1.10 1.35 93% 86% B A A

1.15 1.51 81% 76% C B B

1.20 1.67 69% 63% D D C

1.25 1.82 60% 51% E E D

1.30 1.96 53% 41% F F E

1.35 2.10 48% 34% F F F

1.40 2.23 43% 28% F F F

Truck LOS = function of (on-time arrival, travel time, toll, truck friendliness)

Tables also for signalized urban streets (35-55 mph speeds)

94

TRUCK SPEED TO LOS TABLE

Truck SpeedClass I

Inter-Regional

Class IIPrimary Route

Class IIISupporting

Route

Freeways and Rural Highways

50 mph D D C

45 mph F F E

Signalized Urban Streets

FFS = 55 mi/h 28 mph D C C

FFS = 45 mi/h 23 mph D D C

FFS = 35 mi/h 17 mph E E D

95

TRUCK LOS EXAMPLE COMPS

Link ID TypeTruck

Demand(veh/h)

MixedTTI

TruckSpeed

Adj

TruckTTI

FreightClass

TruckLOS

A001Freeway-Urban

411 6.01 1.1 6.61 I F

A002Arterial-Urban

122 1.87 1.1 2.06 II E

A003Collector-Urban

47 1.14 1.1 1.26 III A

A004Freeway-Rural

279 1.02 1.1 1.12 I B

A005Highway-Rural

119 1.07 1.1 1.17 I B

A006Collector-Rural

15 1.00 1.1 1.10 II A

96

COMMENTS?

Example I.9 – Truck LOS

97

COMMENTS CASE STUDY 1?• Case Study #1 – Long Range Regional Plan




98

CASE STUDY #2 – FREEWAY PROJECT

11:30

99

• 4-6 Lane Interurban Freeway

• 70 miles long,

• Passes through 5 urban areas

• 7% grade over Cuesta Pass

CASE 2 – FREEWAY MASTER PLAN

100

OBJECTIVE

To develop a Corridor Mobility Master Plan to identify current and future mobility problems in the corridor, and establish capital project priorities along the corridor.

101

CASE 2 EXAMPLE PROBLEMS• Example II.1 – Screening for Service Volume Problems

• Example II.2 – Forecasting V/C Hot Spots

• Example II.3 – Estimation of Speed and Travel Time

• Example II.4 – Prediction of Unacceptable Auto LOS Spots

• Example II.5 – Estimation of Queues

• Example II.6 – Prediction of Reliability Problems

102

EXAMPLE II.1 –SCREENING FOR SERVICE VOLUME PROBLEMS• Objective:

• To focus the study on critical auto LOS supersections of freeway

• Approach:

• Step 1: Data requirements• Step 2: Categorize facilities• Step 3: Develop service volume look up table• Step 4: Select focus supersections

103

SERVICE VOLUME TABLES• Maximum traffic volumes that can be accommodated at a

target LOS.

• Auto LOS tables• Freeway, Multilane Hwy, Two-Lane Hwy, Urban Street

• Bus, Bicycle, Pedestrian LOS tables• Truck LOS tables

• They hinge on many underlying assumptions

• Use as a Screening & Scoping Tool

104

FREEWAY SERVICE VOLUME TABLE

K-Factor

D-Factor

Four-Lane Freeways Six-Lane Freeways

LOS C LOS D LOS E LOS C LOS D LOS E

0.08

0.50 75,500 94,100 108,900 113,300 141,100 163,4000.55 68,700 85,500 99,000 103,000 128,300 148,5000.60 62,900 78,400 90,800 94,400 117,600 136,1000.65 58,100 72,400 83,800 87,200 108,500 125,700

0.09

0.50 67,100 83,600 96,800 100,700 125,400 145,2000.55 61,000 76,000 88,000 91,600 114,000 132,0000.60 56,000 69,700 80,700 83,900 104,500 121,0000.65 51,600 64,300 74,500 77,500 96,500 111,700

0.10

0.50 60,400 75,300 87,100 90,600 112,900 130,7000.55 54,900 68,400 79,200 82,400 102,600 118,8000.60 50,400 62,700 72,600 75,500 94,100 108,9000.65 46,500 57,900 67,000 69,700 86,800 100,500

0.11

0.50 54,900 68,400 79,200 82,400 102,600 118,8000.55 49,900 62,200 72,000 74,900 93,300 108,0000.60 45,800 57,000 66,000 68,700 85,500 99,0000.65 42,300 52,600 60,900 63,400 78,900 91,400

105

FREEWAY SERVICE VOLS

Level of ServiceMinimum Peak Direction

VolumeMaximum Peak Direction

Volume

LOS A-C 0 1510 veh/h/lan

LOS D 1510 veh/h/ln 1880 veh/h/ln

LOS E 1880 veh/h/ln 2180 veh/h/ln

LOS F 2180 veh/h/ln infinity

106

DATA REQUIREMENTS• Data

• Facility Type (freeway, highway)• Area type (urban, rural)• Terrain type (level, rolling, mountain)• AADT• K-factor (pk.hr/AADT)• D-Factor (directional factor)

• Split Facility into Supersections

• Combinations of sections• With similar AADT, area type, terrain

107

DETERMINE FACILITY TYPE• Freeway (access controlled)

• Multilane highway

108

SELECT SERVICE VOL TABLE• First verify HCM service volume tables apply.

• Adjust DSV (daily service volume) if necessary.

Required DataDefault Values

Urban Freeways Rural Freeways Urban Highways Rural HighwaysK-Factor 0.08 – 0.11 0.09 – 0.12 0.08 – 0.12 0.09 – 0.12D-Factor 0.50 – 0.65 0.50 – 0.65 0.50 – 0.65 0.50 – 0.65%Trucks 5% 12% 8% 12%%Buses 0% 0% N/A N/A%RVs 0% 0% N/A N/APHF 0.95 0.88 0.93 0.88Ramp Density (/mi.) 3 0.2 N/A N/Afp 1.00 0.85 1.00 1.0Lane Width (ft.) 12 12 N/A N/ALateral Clear (ft.) 6 6 N/A N/AFFS (mph) 65 65 60 60Terrain Level or Rolling Level or Rolling Level or Rolling Level or Rolling

109

ADJUST FOR LOCAL CONDITIONS

Where:DSVi = daily service volume (veh/day)MSFi = maximum service flow (vphpl), HCM Exhibit 11-17 for frwys , Exhibit 14-17 for hwysN = number of lane in each directionfHV = adjustment factor for presence of heavy vehicles in traffic streamfp = adjustment factor for unfamiliar driver populationsPHF = peak-hour factorK = proportion of daily traffic occurring in the peak hour of the dayD = proportion of traffic in the peak direction during the peak hour of the day

DSV=𝑀𝑆𝐹 0×𝑁× 𝑓 𝐻𝑉× 𝑓 𝑝×𝑃𝐻𝐹

𝐾×𝐷×

𝐾 0×𝐷0

𝑁0× 𝑓 𝐻𝑉 , 0× 𝑓 𝑝 ,0×𝑃𝐻𝐹0

Local HCM Table

110

IDENTIFY FOCUS SUPERSECTIONS

Super-Section

Facility TypeArea Type

TerrainFuture AADT

Modified Max AADT (x 1,000)Future

LOSLOS

CLOS

DLOS

E

A 4-ln Highway Urban Level 57,600 59,200 75,700 84,100 A-C

B 4-ln Freeway Urban Level 63,500 62,900 78,400 90,800 D

C 4-Ln Freeway Rural Level 70,100 50,400 62,800 72,700 E

D 4-Ln Freeway Urban Level 55,800 61,000 76,000 88,000 A-C

E 6-Ln Highway Rural Mountain 44,500 52,500 67,100 74,500 A-C

F 4-Ln Freeway Urban Level 58,700 65,800 82,000 94,900 A-C

G 4-Ln Freeway Urban Level 58,800 57,900 72,100 83,500 D

H 4-Ln Freeway Urban Level 32,400 65,800 82,000 94,900 A-C

I 4-Ln Highway Rural Level 19,500 56,400 72,100 80,100 A-C

111

IDENTIFY FOCUS SUPERSECTIONS

Super-Section

Facility TypeArea Type

TerrainFuture AADT

Modified Max AADT (x 1,000)Future

LOSLOS

CLOS

DLOS

E

A 4-ln Highway Urban Level 57,600 59,200 75,700 84,100 A-C

B 4-ln Freeway Urban Level 63,500 62,900 78,400 90,800 D

C 4-Ln Freeway Rural Level 70,100 50,400 62,800 72,700 E

D 4-Ln Freeway Urban Level 55,800 61,000 76,000 88,000 A-C

E 6-Ln Highway Rural Mountain 44,500 52,500 67,100 74,500 A-C

F 4-Ln Freeway Urban Level 58,700 65,800 82,000 94,900 A-C

G 4-Ln Freeway Urban Level 58,800 57,900 72,100 83,500 D

H 4-Ln Freeway Urban Level 32,400 65,800 82,000 94,900 A-C

I 4-Ln Highway Rural Level 19,500 56,400 72,100 80,100 A-C

112

RESULT: FOCUS SUPERSECTIONS• Focus SuperSections

• B – North of Arroyo Grande• C – South of San Luis Obispo• G – South of Paso Robles

• For Rest of this Case Study

• C – South of San Luis Obispo• SB, PM Peak

Section ID’s

113

COMMENTS?

Example II.1 – Use of Service Volumes to screen and scope planning analysis

114

EXAMPLE II.2 – FORECASTING V/C BOTTLENECKS

• Objective:

• To forecast future auto v/c hot spots on facility.• Approach:

• Step 1: Data requirements• Step 2: Selection of defaults• Step 3: Select study boundaries and time periods• Step 4: Identify segment types• Step 5: Estimate free-flow speeds• Step 6: Estimate capacities• Step 7: Assign section demands• Step 8: Compute v/c ratios• Step 9: Interpretation of Results

115

SELECTED SUPERSECTION CSECTIONS 1-3

Los

Oso

s V

all

ey

Rd

S H

igu

era

St

PM 25.911 25.86 24.21 23.97 22.46 22.09 21.28 21.105

Section # C1 C2 C3 C4 C5 C6 C7Section Type Basic Ramps Basic Ramps Basic Ramps BasicLength (mi) 0.05 1.65 0.24 1.51 0.37 0.81 0.18Number of Lanes 2 2 2 2 2 2 2AADT In 41,700 8,600 On-ramp 6,100 On-ramp 1,400 On-rampAADT Out 500 Off-ramp 4,600 Off-ramp 1,400 Off-rampK 0.08 0.08 0.08 0.08 0.08 0.08 0.08% HV and buses 5.81 5.81 5.81 5.81 5.81 5.81 5.81FFS default default default default default default defaultPHF default default default default default default default

SB US101

116

SELECTED SUPERSECTION CSECTIONS 4-7

San

Luis

Bay

Dr

Avila

Bea

ch D

r

PM 25.911 25.86 24.21 23.97 22.46 22.09 21.28 21.105


SB US101

PM 25.911 25.86 24.21 23.97 22.46 22.09 21.28 21.105


SB US101

117

1. DATA REQUIREMENTS• Peak hour factor (peak 15 minutes to peak hour)• Percent heavy vehicles• Peak (K) factor (peak hour to daily)• Segment Type (basis, weave, merge, diverge)• Segment Length• Lanes• Demand (Mainline in, all ramps)

118

DEFAULTS

Required DataDefault Values

Urban Freeways Rural FreewaysK-Factor 0.08 – 0.11 0.09 – 0.12

D-Factor 0.50 – 0.65 0.50 – 0.65

%Trucks 5% 12%%Buses 0% 0%%RVs 0% 0%PHF 0.95 0.88Fp (Driver Population) 1.00 0.85Lane Width (ft.) 12 12Lateral Clearance (ft.) 6 6

119

SELECT STUDY BOUNDARIES & TIME PERIODS

• Review historical information on congestion• Select Peak Period and Direction

• Pick Southbound Direction, Weekday PM Peak period.

120

IDENTIFY SECTION TYPES• Freeway weave section

• Starts with on-ramp• Ends with off-ramp AND• Has auxiliary lane between the two ramps

• Freeway ramp section• Starts with on-ramp, or ends with off-ramp, or both• But no auxiliary lanes between on and off-ramps

• Freeway basic section• Everything else

Ramp Basic Ramp Basic Ramp BasicBasic

Flow

2 3 4 5 6 71

No Weave Sections

121

ESTIMATE FREE-FLOW SPEEDS

Use HCM Method

Or Use Posted Speed Limit

Where:FFS = free-flow speed (mi/h)fLW = adjustment for lane width (mi/h) fLC = adjustment for right side lateral clearance (mi/h)TRD = total ramp density (ramps/mi)PSL = Posted Speed Limit (mi/h)

122

ESTIMATE CAPACITIES

𝒄 𝒊=(𝟐 ,𝟐𝟎𝟎+𝟏𝟎∗ (𝐦𝐢𝐧 (𝟕𝟎 ,𝑺𝑭𝑭𝑺 )−𝟓𝟎) )

𝟏+%𝑯𝑽 /𝟏𝟎𝟎∗𝑪𝑨𝑭

Where:•Ci = capacity of section “I” (vph/ln)•SFFS = Free-flow speed (mph)•%HV = percent of heavy vehicles.•CAF = a capacity adjustment factor that is used to calibrate the basic section capacity given in the HCM to account for influences of ramps, weaves, or other impacts.

Section # C1 C2 C3 C4 C5 C6 C7

Type Basic Ramps Basic Ramps Basic Ramps BasicLength (mi) 0.05 1.65 0.24 1.51 0.37 0.81 0.18Capacity Adjust Factor 1.00 0.95 1.00 0.95 1.00 0.95 1.00

Adj Lane Capacity (vphpl) 2,221 2,110 2,221 2,110 2,221 2,110 2,221Number of Lanes 2 2 2 2 2 2 2Section Capacity (vph) 4,442 4,220 4,442 4,220 4,442 4,220 4,442

123

ASSIGN DEMANDS

Compute Section Demands

• If Demand < Capacity• Sum the mainline in and on-ramp• Subtract off-ramp

• If Demand > Capacity• Do same as before• Reduce demand to capacity• Save up excess demand, add to next time period demand

Flow

3,000

900 800 1,000 500 300 800

3,900 3,100 4,100 3,600 3,900 3,100

2 3 4 5 6 71

124

CONSTRAIN DEMANDS

Example for freeway with capacity = 4,000 vph

5

Flow

3,000

900 800 1,000 500 300 800

3,900 3,100 4,100 3,600 3,900 3,100

Unconstrained

2 3 4 6 71

125

CONSTRAIN DEMANDS

Example for freeway with capacity = 4,000 vph Flow

3,000

900 800 1,000 500 300 800

3,900 3,100 4,100 3,600 3,900 3,100

Unconstrained

3,000

900 800 1,000 489 300 782

3,900 3,100 4,000 3,511 3,811 3,029

Constrained

100

2 3 4 5 6 71

2 3 4 5 6 71

126

COMPUTE D/C AND V/C• Demand/Capacity ratio

• Ratio of demand to capacity

• Volume/Capacity Ratio• Ratio of capacity constrained demand to capacity

Section # C1 C2 C3 C4 C5 C6 C7Sect. Capacity (Ci) 4,442 4,220 4,442 4,220 4,442 4,220 4,442

Time Period 1 (16:00-16:15 )Demand (di,1) 3,336 4,024 3,984 4,472 3,852 3,964 3,852D/C Ratio 0.75 0.95 0.90 1.06 0.87 0.94 0.87

Time Period 2 (16:15-16:30)DEMAND (di,2) 3,791 4,573 4,175 4,981 3,802 3,929 3,802D/C Ratio 0.85 1.08 0.94 1.18 0.86 0.93 0.86



127

INTERPRET RESULTSD/C CONTOUR DIAGRAM

Period 1

Period 2

Period 3

Period 4

C1 C2 C3 C4 C5 C6 C7

Section

V/C Contour Diagram

1.50-2.00

1.00-1.50

0.50-1.00

0.00-0.50

Flow

D/C

128

COMMENTS?

Example Problem II.2 – Auto V/C Bottleneck Identification

129

EXAMPLE II.3 – ESTIMATION OF SPEED AND TRAVEL TIME

• Objective:

• To forecast speeds and travel times on freeway.• Approach:

• Step 1: Estimate delay rates• Step 2: Compute travel times and speeds• Step 3: Interpretation of results

+

Where:DR = delay rate (secs/mi)X = volume/capacity ratioA, B, C, D = parameters

130

SPEED RESULTSSection # C1 C2 C3 C4 C5 C6 C7

FFTravel Rte (s/m) 55.4 55.4 55.4 55.4 55.4 55.4 55.4Length (mi) 0.05 1.65 0.24 1.51 0.37 0.81 0.18

Time Period 1 (0-15 minutes)Delay Rate (s/mi) 1.7 10.1 6.8 31.3 5.4 9.2 5.4Travel Rate (s/m) 57.0 65.5 62.2 86.6 60.8 64.6 60.8Travel Time (sec) 2.9 108.1 14.9 130.8 22.5 52.3 10.9Speed (mph) 62.1 54.9 58.0 41.6 59.2 55.8 59.4

Time Period 2 (15-30 minutes)Delay Rate (s/m) 4.8 36.3 9.2 67.2 4.9 8.7 4.9Travel Rate (s/m) 60.2 91.6 64.6 122.6 60.3 64.1 60.3Travel Time (sec) 3.0 151.2 15.5 185.1 22.3 51.9 10.9Speed (mph) 60.0 39.3 55.7 29.4 59.7 56.2 59.4

Time Period 3 (30-45 minutes)Delay Rate (s/m) 1.7 23.6 9.3 98.8 5.4 9.2 5.4Travel Rate (s/m) 57.0 79.0 64.7 154.2 60.8 64.6 60.8Travel Time (sec) 2.9 130.3 15.5 232.9 22.5 52.3 10.9Speed (mph) 62.1 45.6 55.7 23.3 59.2 55.8 59.4

131

SPEED CONTOUR DIAGRAM

Period 1

Period 2

Period 3

Period 4

C1 C2 C3 C4 C5 C6 C7

Section

Speed Contour Diagram (mph)

60.0-70.0

50.0-60.0

40.0-50.0

30.0-40.0

20.0-30.0

10.0-20.0

0.0-10.0

132

COMMENTS

Example Problem II.3 – Freeway Speed and Travel Time Estimation.

133

EXAMPLE II.4 –UNACCEPTABLE AUTO LOS HOT SPOTS

Objective:

To predict auto LOS problems

Approach:

Step 1: Estimate density and auto LOS

Step 2: Interpretation of results

Density = 1.2*

Freeway SegmentsLevel of Service Density (pc/mi/ln)

A <= 11B >11-18C >18-26D >26-35E >35-45F >45 or v/c>1.00

134

COMMENTS?

Example Problem II.4 – Freeway Auto LOS Analysis

135

EXAMPLE II.5 – ESTIMATION OF QUEUES

• Objective:

• To forecast queuing problems on freeway.• Approach:

)

Section Number 1 2 3 4 5 6 7

Length (mi.) 0.05 1.65 0.24 1.51 0.37 0.81 0.18

Number of Lanes 2 2 2 2 2 2 2

Section Capacity (vph) 4,442 4,220 4,442 4,220 4,442 4,220 4,442Time Period 1 (0-15 minutes)

Demand (vph) 3,336 4,024 3,984 4,472 3,852 3,964 3,852

V/C Ratio 0.75 0.95 0.90 1.06 0.87 0.94 0.87

Density (vpmpl) 26.9 36.6 34.4 50.8 32.5 35.5 32.4

Estimated Queue (mi.) 2.48

Actual Queue (mi.) 0.73 0.24 1.51

136

COMMENTS?

Example Problem II.5 – Freeway Queuing Analysis

137

EXAMPLE II.6 – PREDICTION OF RELIABILITY PROBLEMS

• Objective:

• To forecast reliability for freeway.• Approach:

• Step 1: Data requirements• Step 2: Identify segment types• Step 3: Identify demand variability• Step 4: Identify weather events• Step 5: Identify incidents• Step 6: Identify work zones• Step 7: define reliability analysis scenarios• Step 8: Compute hourly travel times• Step 9: Compute reliability statistics• Step 10: Interpret results

138

DATA FOR RELIABILITY ANALYSIS

Data TypeInput or

Default Values Data SourceVolume (AADT) Input Caltrans/Travel ModelNumber of lanes Input Aerial MapLength (miles) Input Caltrans/Aerial MapK-Factor Input CaltransD-Factor Input CaltransSeasonal Adjustment Factor Input CaltransWork Zone Capacity (vphpl) 1,600 HCM Exhibit 10-14Incident Capacity Reduction Input HCM Exhibit 10-17Work Zone Avg. Lane Closes 1 DefaultRainfall Intensity (inches) Input Weather UndergroundAvg. Blocking Incident Duration (minutes) Input CaltransAvg. Non-blocking Incident Duration (minutes) Input CaltransTotal Number of Blocking Incidents Input CaltransTotal Number of Non-blocking Incidents Input CaltransFree-flow Speed Reduction for Light-Rain 6.00% Default Free-flow Speed Reduction for Heavy-Rain 12.00% DefaultArea Type Input Local KnowledgeAnalysis Period Input Local KnowledgeFacility Type Input HCM

139

RELIABILITY RESULTS

SectionComputed 95%TTI

Daily AM (7-9) PM (4-6)

C1 1.10 1.12 1.14

C2 1.89 1.89 1.75

C3 1.07 1.08 1.14

Good, Bad, or Ugly?

140

RELIABILITY RESULTS(2)

SectionComputed 95%TTI

Daily AM (7-9) PM (4-6)

C1 1.10 B 1.12 B 1.14 B

C2 1.89 E 1.89 E 1.75 D

C3 1.07 A 1.08 B 1.14 B

Good, Bad, or Ugly?

Level of Service

5% Speed 95% TTI

A >60 mi/h <1.08B 55-60 1.08-1.18C 45-55 1.18-1.44D 35-45 1.44-1.86E 25-35 1.86-2.60F <=25 >= 2.60

Draft FDOT LOS Scale

141

COMMENTS?

Example Problem II.6 – Freeway Reliability Analysis

142

COMMENTS CASE STUDY 2?• Case Study #2 – Freeway Master Plan




143

CASE STUDY #3 – URBAN STREET BRT

14:00

144

• 14 mile urban street

• BRT to take 2 thru lanes

CASE 3 – URBAN STREET BRT PLAN

145

OBJECTIVE

to identify the traffic, transit, pedestrian, and bicycle impacts of the proposed BRT project.

146

CASE 3 EXAMPLE PROBLEMS• Example III.1 – Screening for Service Volume Problems

• Example III.2 – Screening for Auto Choke Points

• Example III.3 – Forecasting V/C Ratios

• Example III.4 – Auto and BRT Speeds/Travel Times

• Example III.5 – Predicting Queues

• Example III.6 – Predicting Reliability Problems

• Example III.7 – Transit, Bicycle, Pedestrian LOS

147

EXAMPLE III.1 –SCREENING FOR SERVICE VOLUME PROBLEMS• Objective:

• To focus the study on critical auto LOS supersections of BRT project

• Approach:

• Step 1: Divide BRT route into supersections• Step 2: Obtain AADTs • Step 3: Identify service volumes• Step 4: Identify supersections for further analysis

148

DIVIDE BRT ROUTE INTO SUPERSECTIONS• Divide route into supersections

• Divide at points where there are significant changes in:• Posted speed limit• Number of through lanes• Median• Demand

149

SUPERSECTIONSStreet Limits

Length (mi)

AADTSpeed Limit (mi/h)

Lanes + Median

Telegraph Ave. Dwight to Woolsey 0.84 16,570 25 4

Telegraph Ave Woolsey to SR 24 0.80 18,340 30 4

Telegraph Ave SR 24 to 45th St. 0.60 16,540 30 5

Telegraph Ave 45th St. to Broadway 2.01 16,230 25 5

International Bl. Lake Merritt to 23rd Ave 1.58 10,220 30 4

International Bl. 23rd Ave to 35th Ave. 0.87 13,370 25 4

International Bl. 35th Ave to High St. 0.51 15,910 25 5

International Bl. High St. to Hegenberger 1.78 13,560 30 5

International Bl. Hegenberger to 98th Ave. 1.37 14,830 30 5

International Bl. 98th Ave to Dutton 1.06 11,180 30 5

150

SIGNALIZED STREET SERVICE VOLUME TABLE

Two-Lane Streets Four-Lane Streets

K Factor D Factor LOS C LOS D LOS E LOS C LOS D LOS E

Posted Speed = 30 mi/h

0.090.55 5,900 15,400 19,900 11,300 31,400 37,9000.60 5,400 14,100 18,300 10,300 28,800 34,800

0.100.55 5,300 13,800 17,900 10,100 28,200 34,1000.60 4,800 12,700 16,400 9,300 25,900 31,300

0.110.55 4,800 12,600 16,300 9,200 25,700 31,0000.60 4,400 11,500 14,900 8,400 23,500 28,400

Posted Speed = 45 mi/h

0.090.55 10,300 18,600 19,900 21,400 37,200 37,9000.60 9,400 17,100 18,300 19,600 34,100 34,800

0.100.55 9,300 16,800 17,900 19,300 33,500 34,1000.60 8,500 15,400 16,400 17,700 30,700 31,300

0.110.55 8,400 15,300 16,300 17,500 30,500 31,0000.60 7,700 14,000 14,900 16,100 27,900 28,400

151

SERVICE VOLUME TABLES BACKINGService Volume Tables are backed by a long list of assumptions:

General assumptions for urban street table:

• Coordinated, semi-actuated traffic signals;

• arrival type 4; 120-s cycle time; protected left-turn phases; 0.45 weighted average g/C ratio;

• Exclusive left-turn lanes with adequate queue storage provided at traffic signals; no exclusive right-turn lanes provided;

• no restrictive median; 2-mi facility length; 10% of traffic turns left and 10% turns right at each traffic signal;

• Peak hour factor = 0.92; and base saturation flow rate = 1,900 pc/h/ln.

• For 30-mi/h facilities: signal spacing = 1,050 ft and 20 access points/mi.

• For 45-mi/h facilities: signal spacing = 1,500 ft and 10 access points/mi.

• (Adapted from Exhibit 10-8, 2010 HCM)

152

SIGNAL STREET SERV. VOLS

Level of Service 30 mi/h Street 45 mi/h Street

LOS A-C < 270 veh/h/ln < 510 veh/h/ln

LOS D 270-760 veh/h/ln 510-890 veh/h/ln

LOS E 760-900 veh/h/ln 890-900 veh/h/ln

LOS F > 900 veh/h/ln > 900 veh/h/ln

Entries are Peak Direction, Peak Hour volumes averaged across through lanes in peak direction

A two lane street (one lane each direction) may be able to carryAbout 10% more volume before going from LOS E to F.

153

SERVICE VOLUME SCREENING

Street Limits AADT

Before BRT After BRTFurther

Analysis?Lanes

Max LOS D

LanesMax LOS

D

Telegraph Ave. Dwight to Woolsey 16,570 4 28,200 2 13,800 Yes

Telegraph Ave Woolsey to SR 24 18,340 4 28,200 2 13,800 Yes

Telegraph Ave SR 24 to 45th St. 16,540 5 28,200 3 13,800 Yes

Telegraph Ave45th St. to Broadway

16,230 5 28,200 3 13,800 Yes

International Bl.Lake Merritt to 23rd Ave

10,220 4 28,200 2 13,800 No

International Bl.23rd Ave to 35th Ave.

13,370 4 28,200 2 13,800 No

International Bl. 35th Ave to High St. 15,910 5 28,200 3 13,800 Yes

International Bl.High St. to Hegenberger

13,560 5 28,200 3 13,800 No

International Bl.Hegenberger to 98th Ave.

14,830 5 28,200 3 13,800 Yes

International Bl. 98th Ave to Dutton 11,180 5 28,200 3 13,800 No

154

FOR FURTHER ANALYSIS• 6 out of 10 supersections selected for further analysis.

• For rest of case study will focus on one supersection.

Street LimitsLength

(mi)AADT

Posted Speed Limit (mi/h)

Before BRT After BRT

LanesMax

LOS DLanes

Max LOS D

Telegraph Ave

SR 24 to 45th St.

0.60 16,540 30 5 28,200 3 13,800

155

COMMENTS?

Example Problem III.1 – Urban Street Screening Analysis

156

EXAMPLE III.2 – SCREENING FOR V/C HOT SPOTS

• Objective:

• To identify future auto v/c hot spots for further analysis.• Approach:

• Step 1: Obtain data• Step 2: Compute critical lane volumes• Step 3: Interpretation of results

• V/C hot spots usually at signalized intersections• Can be other major intersections.

157

DATA

158

SUM UP CRITICAL LANE VOLS• Convert all turn moves to equivalent per lane volumes

• Find Maximum North-South street critical lane volume

• NB Left + SB Thru• SB Left + NB Thru

• Find Maximum East-West street critical lane volume

• EB Left + WB Thru• WB Left + EB Thru

• Sum up maximum critical lane volumes

• Compare to 1500

• If sum of critical lane volumes > 1500, further analysis…

159

CRITICAL LANE ANALYSIS

N/S StreetE/W Street

NBL+SBT

SBL +NBT

MaxN/S

EBL+WBT

WBL+EBT

MaxE/W

CriticalSum

Is it<1500?

Telegraph 45th St 509 715 715 252 290 290 1005 OK



Telegraph 51st St 636 1018 1018 710 466 709.5 1728 Not OK

Telegraph Claremont 794 582 794 160 136 160 954 OK


160

INTERPRETATION• Critical lane analysis overlooks a lot of subtleties.

• Left turn protection is treated same as permitted• Heavy truck volumes, narrow lanes, parking interference• Pedestrian crossing constraints ignored.

• It tells you where there may be problems, but not if there are problems.

• It may miss non-standard problems.

• For rest of Case Study will focus on the one intersection that failed the critical lane check: Telegraph and 51st St.

161

COMMENTS?

Example Problem III.2 – Intersection Screening Analysis

162

EXAMPLE III.3 – INTERSECTION V/C

• Objective:

• To forecast intersection volume/capacity ratios.• Taking into account more factors than critical lane.

• Approach:

• Step 1: Required data• Step 2: Determine left turn phasing• Step 3: Convert turns to pce’s• Step 4: Assign volumes to lane groups• Step 5: Calculate critical lane group volumes• Step 6: Compute intersection v/c

163

INTERSECTION V/C INPUT

Signalized Intersection Planning Method, Input Worksheet (Part 1)Telegraph Avenue and 51st Street

NB SB EB WB LT TH RT LT TH RT LT TH RT LT TH RTVolume 83 794 59 283 505 22 294 763 80 91 582 111Lanes 1 1 1 1 2 2 1 2 PHF 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 % HV 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Parking activity

Yes Yes Yes Yes

Ped activity Med Med Med MedLT phasing Protected Protected Protected Protected

164

INTERSECTION V/C OUTPUTSignalized Intersection Planning Method, Calculations (Part 1)

Telegraph Avenue and 51st Street NB SB EB WB LT TH RT LT TH RT LT TH RT LT TH RT Step 1. Determine LT phasingCheck #1 LT<200 LT>200 LT>200 LT<200

Check #2 Not exceed a given Threshold Exceed a given Threshold Exceed a given ThresholdNot Exceed a given

ThresholdCheck #3 1 LT lane 1 LT lane 2 LT lanes 1 LT laneLT phasing Protected Protected Protected Protected Step 2. Convert turning movements to passenger car equivalentsEHVadj 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05

EPHF 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09

ELT

ERT 1.3 1.3 1.3 1.3

EP 1.2 1.2 1.2 1.2

ELU 1.05 1.03 1.05 1.05

vadj 95 909 105 324 607 39 347 917 143 104 699 198 Step 3. Assign volumes to lane groupsvi (pc/h/ln) 95 1014 324 646 174 530 104 449 Step 4. Calculate critical lane groupsvcEW

vcNS

vcNS=1338 vcEW=634

vc 1972 Step 5. Intersection volume-to-capacity ratiovc/ci 1.20 (Use Default ci=1650 pc/h/ln)

Intersection sufficiency

Over Capacity

165

COMMENTS?

Example Problem III.3 – Intersection V/C Analysis

166

EXAMPLE III.4 – ESTIMATE SPEEDS FOR AUTO AND BRT

• Objective:

• To predict auto and BRT speeds• Approach:

• Step 1: Estimate midblock free-flow speeds• Step 2: Estimate intersection delays• Step 3: Check for mid-block delays• Step 4: Compute segment speed• Step 5: Estimate BRT speed• Step 6: Aggregate to facility level

167

ESTIMATE AUTO SPEED

𝑇 𝑖=3600𝐿𝑖𝐹𝐹𝑆

+𝑑𝑖𝑛𝑡+𝑑𝑚𝑏

𝑆 𝑖=3600𝐿𝑖𝑇 𝑖

Where:Ti = travel time segment “I”Li = length of segmentDint = delay at intersectionDmb = mid-block delaySi = average speed segment “I”

Auto speed = 7.4 mphLOS = F

168

ESTIMATE BUS SPEED

𝑇 𝑖 ,𝑏𝑢𝑠=5,280𝐹𝐹𝑆3,600𝐿𝑖

+𝑑𝑖𝑛𝑡 ,𝑏𝑢𝑠+𝑑𝑚𝑏+𝑑𝑏𝑠

whereTi,bus = base bus travel time for segment i (s),FFS = midblock free-flow speed from Equation H-1 (mi/h),5,280 = number of feet per mile,3,600 = number of seconds per hour,Li = Length of segment i (ft),dint,bus = average bus traffic signal delay not part of dwell time (s),dmb = midblock bottleneck delay (if any) (s), anddbs = total bus stop delay in the segment (s).

Bus Speed = 20.3 mphAt frequency = 4/hr, LOS = A-C

169

COMMENTS?

Example Problem III.4 – Auto and Bus Speed Analysis

170

EXAMPLE III.5 – ESTIMATION OF QUEUES

• Objective:

• To forecast queuing problems on street.• Approach:

𝑄𝑢𝑒𝑢𝑒=𝐴𝑣𝑒𝐷𝑒𝑙𝑎𝑦∗𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦

3600

Signalized Intersection Planning Method - Queue Calculations

NB SB EB WB LT TH RT LT TH RT LT TH RT LT TH RTCapacity (veh/h) 269 839 269 839 95 443 95 443 Ave Delay (s) 47 33 52 28 57 46 57 46 Ave Queue (veh) 4 8 4 7 2 6 2 6

171

COMMENTS?

Example Problem III.5 – Urban Street Queue Analysis

172

EXAMPLE III.6 – PREDICT RELIABILITY

• Objective:

• To forecast reliability for urban street.• Approach:

• Step 1: Data requirements• Step 2: Identify segment types• Step 3: Identify demand variability• Step 4: Identify weather events• Step 5: Identify incidents• Step 6: Identify work zones• Step 7: Define reliability analysis scenarios• Step 8: Compute hourly travel times• Step 9: Compute reliability statistics• Step 10: Interpret results

173

RELIABILITY RESULTSDifferent Scenarios During PM Peak Hour Probability

Speed (mph)

Congested with rain and work zone 0.18% 5.9Congested with rain, incident, work zone 0.00% 5.9Congested with work zone 0.27% 6.0Congested with incident and work zone 0.00% 6.0Congested with rain and incident 0.40% 6.0Congested with incident 0.60% 6.2Non-congested with rain and work zone 0.01% 14.0Non-congested with rain, incident, work zone 0.00% 14.0Non-congested with rain and incident 0.02% 14.2Non-congested with work zone 0.03% 14.7Non-congested with incident and work zone 0.00% 14.7Non-congested with incident 0.07% 14.9Non-congested with rain 38.27% 15.0No Congestion, No Rain, No Incident, No Work Zone 60.14% 15.8

Weekday PM Peak Hours of the Year 95% TTI = 2.34

174

COMMENTS?

Example Problem III.6 – Urban Street Reliability Analysis

175

EXAMPLE III.7 – TRANSIT, BIKE, PED LOS

• Objective:

• To forecast transit, bike, ped LOS.• Procedure:

• Step 1: Data requirements• Step 2: Compute transit LOS • Step 3: Compute bicycle LOS• Step 4: Compute pedestrian LOS

In Progress

176

COMMENTS SO FAR?• Case Study #3 – BRT Planning




177

CASE STUDY #4 – SYSTEM MONITORING

14:45

178

CASE 4 – SYSTEM MONITORING• State produces annual report on state highway system

performance.

• Over 12,000 center-line miles,

• 28,000 directional segments

• Three different monitoring station types

• Some collect AADT only (e.g. HPMS)• Some collect Hourly speed data only (e.g. INRIX)• Some collect simultaneous hourly spot speeds and

volumes (loop detectors)

179

CASE 4 – EXAMPLE PROBLEMS

For All System Performance Monitoring Sites

• Example IV.1 – Estimate Site Capacities & Free-Flow Speeds

For Volume Only Monitoring Sites

• Example IV.2– Estimate Site Speeds from Volumes

For Travel Time Only Monitoring Sites

• Example IV.3 – Estimate Site Volumes from Speeds

For All Performance Monitoring Systems

• Example IV.4 – HCM Assisted QA/Quality Control• Example IV.5– Computation of Modal Performance Measures

180

EXAMPLE PROBLEM IV.1 – SITE CAPACITIES AND FFS

Objective:

• Need monitoring site capacities and free-flow speeds to compute various performance measures.

Approach:

• Use same method as used in areawide studies to develop capacity and free-flow speed look up tables by facility type and area type.

181

CAPACITY AND FFS TABLE


(mph)Capacity(veh/ln)

Freeway

Downtown 55 1800

Urban 60 1800

Suburban 65 1900

Rural 70 1900

Arterial

Downtown 25 700

Urban 35 700

Suburban 45 600

Rural Multi-Lane 55 1700

Rural 2-Lane 55 1300

Collector

Downtown 25 600

Urban 30 600

Suburban 35 600

Rural Multi-Lane 45 1500

Rural 2-Lane 45 1300

182

EXAMPLE IV.2 – ESTIMATE SPEEDS FROM VOLUMES

Objective:

• To estimate speeds for sites that collect only volume data.

Approach:

• Use Akcelik equation to compute speed from v/c ratio and free-flow speed.

183

INPUT

Site ID

Length(mi)

Lanes AADT K DFacility

TypeArea Type

Pk Hr(veh/h)

PkDir(veh/h)

A0010.85 8 175,800 0.085 0.55 Freeway Urban 14,940 8,220

A002 0.21 6 34,500 0.092 0.55 Arterial Urban 3,170 1,740

A003 1.34 4 22,700 0.094 0.55 Collector Urban 2,130 1,170

A004 2.50 4 53,400 0.095 0.55 Freeway Rural 5,070 2,790

A005 4.50 4 28,200 0.096 0.55 Highway Rural 2,710 1,490

A006 7.30 2 4,600 0.098 0.55 Collector Rural 450 250

184

ESTIMATED SPEEDS

Site ID

Length(mi)

TypeFree Spd

(mi/h)Cap/Ln J Cap v/c Spd (mi/h)

A001 0.85 Frwy-Urb 60 1800 8.40E-06 7,200 1.14 10.0

A002 0.21 Art-Urb 35 700 9.34E-06 2,100 0.83 18.7

A003 1.34 Coll-Urb 30 600 9.34E-06 1,200 0.98 26.2

A004 2.50 Frwy-Rural 70 1900 1.99E-05 3,800 0.73 68.7

A005 4.50 Hwy-Rural 55 1700 9.34E-06 3,400 0.44 51.5

A006 7.30 Coll-Rural 45 1300 2.31E-05 1,300 0.19 44.8

185

COMMENTS?

Example Problem IV.2 – Estimating Speeds from Count Data

186

EXAMPLE IV.3 – ESTIMATE VOLUMES FROM SPEEDS

Objective:

• To estimate volumes to associate with measured speeds.

Approach:

• Back solve Akcelik equation to determine volumes from measured speeds.

AB

AAX

2

22

H

TTA

25.00

2

2*16

H

LJB

Where: x = the link demand/capacity ratio;A= composite variable defined at left.B = composite variable defined at left.T = link travel time (h), To = link travel time at free-flow link speed (h),H = the expected duration of the demand (typically one hour) (h);x = the link demand/capacity ratio;L= the link length (mi).J = the calibration parameter

187

INPUT SPEED MONITOR DATA

Site IDLength Lanes

Spd (mi/h)

Facility Type

Area Type K D

A0010.85 8 10.0 Freeway Urban 0.085 0.55

A0020.21 6 18.7 Arterial Urban 0.092 0.55

A0031.34 4 26.2 Collector Urban 0.094 0.55

A0042.50 4 68.7 Freeway Rural 0.095 0.55

A0054.50 4 51.5 Highway Rural 0.096 0.55

A0067.30 2 44.8 Collector Rural 0.098 0.55

188

ESTIMATED VOLUMES

Site IDLengt

hType

Free Spd

Cap/Ln J Cap A B v/c

A001 0.85 Frwy-Urb 60 1800 8.40E-06 7,200 0.283724 9.71E-05 1.14A002 0.21 Arterial-Urb 35 700 9.34E-06 2,100 1.59E-05 6.59E-06 0.83A003 1.34 Collector-Urb 30 600 9.34E-06 1,200 0.004776 2.68E-04 0.98A004 2.50 Frwy-Rural 70 1900 1.99E-05 3,800 0.002734 1.99E-03 0.73A005 4.50 Hiwy-Rural 55 1700 9.34E-06 3,400 0.001179 3.03E-03 0.44A006 7.30 Collect-Rural 45 1300 2.31E-05 1,300 0.002341 1.97E-02 0.19

Site ID Length Type v/c Pk Dir Pk Hr (2wy) AADTA001 0.85 Freeway-Urban 1.14 8,220 14,950 175,900A002 0.21 Arterial-Urban 0.83 1,740 3,160 34,300A003 1.34 Collector-Urban 0.98 1,170 2,130 22,700A004 2.50 Freeway-Rural 0.73 2,790 5,070 53,400A005 4.50 Highway-Rural 0.44 1,490 2,710 28,200A006 7.30 Collector-Rural 0.19 250 450 4,600

189

COMMENTS?

Example Problem IV.3 – Estimating Volumes from Speed Data

190

EXAMPLE IV.4 – HCM ASSISTED QA/QC

Objective:

To error check monitoring data for aberrations

Approach:

Step 1: compare volumes to capacity

Step 2: compare measured free-flow speeds to HCM

Step 3: check consistency of measured speeds and flows against standard speed-flow curves.

191

BEFORE CALIBRATION

192

AFTER CAPACITY AND SPEED CALIBRATION

193

COMMENTS?

Example Problem IV.4 – QA/QC of Speed and Volume Monitoring Data

194

EXAMPLE IV.5 – MODAL SYSTEM PERFORMANCEObjective:

To compute modal system performance measures.

Approach :

Step 1: Compute Auto, truck VMT and PMT

Step 2: Compute % VMT by LOS

Step 3: Compute reliability

Step 4: Compute vehicle-hours of delay

Step 5: Compute vehicle-hours in queue

Step 6: Compute v/c

Step 7: Compute % system miles by bike LOS

Step 8: Compute % system miles by pedestrian LOS

195

COMMENTS CASE STUDY 4?• Case Study #4 – System Monitoring




196

4. WRAP UP

15:15

197

WRAP UP

1. What do you like the most about the guide & case studies?

2. What do you dislike the most about the guide & case studies?

3. What is missing?

4. Will you find it useful? Would you recommend it to others?

198

NEXT STEPS

Next steps:

- Guide goes to highway capacity committee January 2015

- Draft Final goes to panel March 2015.

- Publication in one year.

199

OUR THANKS TO OUR HOSTS

Comments

- Tom Creasey [email protected]

- Rick Dowling [email protected]

Documents

PLANNING AND PRELIMINARY ENGINEERING GUIDE FOR USING THE HIGHWAY CAPACITY MANUAL NCHRP 7-22 WORKSHOP 1