Intro to Access Management Principles

7/28/2019 Intro to Access Management Principles

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Access Management Principles

Introduction and Overview

Right to

propertyaccess

Efficient

traffic

throughput

Neil SpillerFHWA, Washington, D.C.


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Introduction to AccessManagement Principles

2

Presentation

General overview Benefits and Consequences

Access Management in Practice

Elements of an AM Program


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3

Part 1

Overview


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4

What is Managing Access?

DrivewaysMedian Openings

Traffic Signals

Interchanges

Managing and Planning the Spacing and Design of:


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Definition of AM

FORMAL: Access management is theprogrammatic control of the location,

spacing, design, and operation ofdriveways, median openings,interchanges, and street connections to aroadway. (TRB Manual)

INFORMAL: Where the road meets thedriveways


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Purpose of AM:Balance Mobility vs. Access

Freeways

Major Arterials

Minor Arterials

Major Collectors

Minor Collectors

Local Streets


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A Very Brief History of AM

part 1 of 4

New Jersey 1902established speedways forhorses and bicycles. No public streets or other

highways shall cross or intersect the speedwayat grade without consent of the county

U.S. Supreme Court 1906 decided that access

control along highways was a sovereign power

of the states.


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part 2 of 4

Between 1900 and 1920 the number ofautomobiles grew from 8K to 10M and lobby

groups emerged (e.g., AAA and AASHO)

1919- DDE undertook a transcontinental militaryconvey from D.C. to San Francisco (62 days)

1921 Federal-Aid act established a system ofnational routes


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part 3 of 4

In 1920s it became apparent that automobile (related)deaths were soaring.

In 1937 NY and RI established the first statewide statutes

that included abutting access control and requiredpermits and reviews as part of their state route adoptionplan

By late 1940s almost every state legislated permitting

accesses to some degree and court decisions began toconfirm that public safety and mobility essentiallytrumped a landowners absolute right to access at anypoint


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Basic right to access

A property ownerhas right to have access

(i.e., not to be landlocked)

but does NOT have right to expect absoluteaccess at any point,

NOR should they expect compensation for

relocated access as long as the governmentshows justifiable cause and least-impact.


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part 4 of 4

National standards for individual driveway design weredeveloped in 1960 AASHO An Informational Guidefor Preparing Private Driveway Regulations for MajorHighways

NCHRP Report 121 (1971) Protection of HighwayUtility stands as one of the earliest, most recognizeddiscussions of access control

Beginning of modern AM credited to Colorado, 1979,when they created 1st comprehensive principals of AMand spelled out the safety, aesthetic and delay-reducingbenefits of AM incorporated into statute


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Colorado, 1979

The lack of adequate access management on the highway

system and theproliferation of driveways andother access approaches is a major contributor to

highway accidents and the greatest single factor behindthe functional deterioration of highways in this state. Asnew accesses are constructed and signals erected, thespeeds and capacity of the roadways decrease, andcongestion challenges to the motorist increase.

-- Colorado State Highway Access Code


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National Perspective

The lack of access control along arterial

highways has been the largest single factor

contributing to the obsolescence of highway

facilitiesNCHRP Report 121 Protection of Highway Utility

Every study since the 1940s has indicated a

direct and significant link between access

frequency and accidentsInternational R/W Assoc. conference paper, 1999


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Part 2

Benefits and Consequences


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Driveways are inevitable and

necessary but as their numbers go

up, so too does the propensity foraccidents in that corridor.


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Benefits of AM

Preserve integrity of the roadway system

Improve safety and capacity

Extend functionallife of the roadways

Preserve public investment in infrastructure Preserve private investment in properties

Provide a more efficient (and predictable)motorist experience

Improve thru times through a corridor Improve aesthetics(less pavement, more green)


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Groups Who Benefit

Which groups will benefit from good AM?

Motorists Cyclists

Peds

Business Owners

Communities


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% of Driveway Crashes by

Movement

47%

16%

27%

10%

Heres a scoop!

The majority of

access-related

crashes involve

LTs (63%)


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Composite Crash Rate Indices

0

1

2

3

4

5

10 20 30 40 50 60

11.3

1.72.1

2.8

4.1

# Access Points per Mile

Crash

Index:Ratioo

fcrashesto

A

ccessPointsp

erMile

Crash rate indices increase as # ofaccess points per mile increases


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AM in the

Transportation andLand Use Cycle

AM applied

here

through

physical

means

AM applied

here through

administrative

means


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Over-arching Goal of AM:

Limit the number and impact of driverdecision and conflict points fromimpacting on through traffic.

Whats the bottom line?


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Conflicts, contd

Think of a single traffic conflict as one rock in a

pond. The ripples are easy to see and are

predictable. However, when dozens of rocks are

thrown in at once, the ripples are dynamic, theycreate chaos, and it is difficult to avoid one at

the cost of another.

Traffic Conflict


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Introduction to AccessManagement Principles 23

Conflict Points

Each access point creates potential conflicts

between through traffic and turning traffic.

Diverge MergeCross

Stop / Queue Weave


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Conflicts

(and dont forget pedestrian and bicycle movements too!)

o 16 Crossing

8 Diverge

8 Merge

32 TOTAL

o 1 Crossing

3 Diverge

4 Merge

8 TOTAL


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Consequences of Poor AM

Increase in crashes and crash rates

Poor capacity throughput

Increased delays

Reduced roadway efficiency Potential for unsightly strip development

Decreased property values

Potential for unwanted cut-thru traffic

Potential for less desirable experience, hence,less customers will want to make the trip


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Effect of Speed Differential to

Propensity for Crashes

0

20

40

60

80

100

3.3x

23x

90x

RelativeCrash

Ratio

Speed Differential (MPH)

+10 MPH +20 MPH +25 MPH10

Baseline

(20) (30) (35)


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How to improve

Consequences

Unclutter the corridor (Pruning)

Direct where driveways are best suited

Assign turn movements by defining andseparating them

Develop guidelines for property access,

thru traffic, and hierarchy of streets Enforce against violations and poorpractices in siting driveways and streets


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Part 3

Access Management in Practice


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Use non-traversable

medians to separate

traffic and direct

motorists where to

access properties.

Use turn lanes to queue

separate movements and

to free up throughmovements


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Driveway Bypass Lane

Where restricted from placing a median, can

you install a bypass lane?


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Median Redesign

Note:

1) increased separation between intersections2) Introduction of U-turns to replace former movements


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Colfax

AveAlameda

Ave FederalBlvd WadsworthAve HavanaAve ParkerDr ArapahoeAve02468

101214 Regular Arterials

Accidents

Per MillionMiles

Traveled

12.912.5 12.9

7.210.5

5.03.5

Source:"Colorado

Access Control

Demonstration

Project" - 1985

Highly

Access

ManagedArterials

Access Management

Results

Fewer accidents on Managed roads

R lt


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Effects of Access Management on travel speeds in the P.M. peak hour

ColfaxAlameda

FederalWadsworth

HavanaParker

Arapahoe

0 10 20 30 40 50Speed (mph)

2328

2525

30

"RegularArterials

Highly Accessed-Managed Arterials4846

Access Management

Results

Higher thru speeds on Managed roads


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Signal Spacing Variables

Tweak these . . .

Intersection spacing

Overall cycle lengths Cycle phasing

To Seek these . . .

Progression speed Progression efficiency


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Relationship between cycle

length, signal spacing, and speed

-mile 1/3 - mile -mile

30 MPH 60 sec 80 sec 120 sec

40 MPH na 60 sec 100 sec

50 MPH na 50 sec 80 sec


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What methods are used?

Permits, legislation and corridor planning

Medians

Auxiliary lanes

Signals and signal spacing

Driveway location, spacing, and design

Corner clearance

Cross-access and joint access Frontage roads and connectors


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Who is Responsible for AM?

Professionals that guide urban development Planners

Engineers

Architects

Approval agents (Boards, Councils, etc.)

Developers Land use attorneys

Agency staff

Non professionals

Citizens, motorists

Property Owners

Ad-hoc groups (pedestrians, bicycles, social change)


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What is

Functional Intersection Areaand why is this important?

The influence area associated with a drivewayincludes

The impact length (distance back at which carsbegin to be affected)

Perception-reaction distance

And the car length

Upstream length > Downstream length


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Functional Intersection Area

The upstream and

downstream areas of

influence that affect

driver decision. Notethat closely spaced

driveways and

intersections have

overlapping areas.

Elements that impact the functional intersection area:

stopping sight distance; RT-out acceleration; slowing to

turn; perception-reaction time; queue storage; etc., are

there more?


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Application of Access

Window

Window for left or right

Window for RT only

No window on higher street


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Different types of Access

Controls

Police power

Eminent domain

Condemnation

Statutes and statutory designation


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Introduction to Access

Management Principles

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In plain English?!

An agency uses eminent domain topurchase or takethe right of access.

An agency uses theirpolice power toapprove or deny the application for adriveway and impart public safety


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Part 4



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Have administrative rules, ordinances or guidelines

Educate your boards, councils, and public

Establish an approval authority

Have geometric design standards

Provide staff training and education re: policies

Monitor approvals (inspect) and conduct agency evaluations

Develop an request/approval process and fees, etc.

Provide consistent and justifiable application of standards Document meetings, contacts, and written communications

Allow for appeals and justified deviations/exceptions


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Schools SportsAccess

Management

Oversight School Board OwnerMayor, Council,

Board

Leadership Principal Coach DPZ, DPW

Day-to-day

executionTeachers Players Staff

Guiding principles Lesson Plans Playbook, rules Design statutes

Stakeholders Parents FansMotorists and

property owners

Product GraduatesQuality of effort

and wins / losses

Improved traffic

progression,

safety

Every stakeholder needs to be on board with the plan and aware of

the consequences of, and need for, guidance, structure and goal


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Have a plan stick to it!

uncontrolled access over time

controlled access via permitting


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Levels of Approval

Federal interstates / State highways

Local highways and streets

Local site plan approvals must meet other

agencies regulations (zoning, R/W, EPA) Adopted Master Plans

Zoning and long range planning must beconsidered

Other stakeholders? Adjacent/abutting propertyowners? Public?

T ffi I t St d A


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Very small site or re-use

Owner-transfer, same use-upgrade

or isolated (i.e., non urban) location

Small site, local impact

Bank, restaurant, gas station

Medium site, destination

oriented Small strip retail,small office or residential complex

Large site, regionally

impacting Shopping center,large residential/retail complex, big-

box store

Scope:

Driveway only or

nearest intersection

Closest

intersections up-

and down stream

Radius of

neighborhood

intersections

Large cordon of

intersections,

including major

connections

Traffic Impact Study Areas


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FHWAs Role

To champion the role that AM serves inimproving safety and reducing delay

Increase awareness of, and benefits of . .

To sponsor AM-related studies and enable

academic research To educate (through NHI courses, et al)

Key Products

AMDVD

Benefits of

Access

Management

Tri-fold

AM Resource

DVD

Public

Meeting

Handout

and CDCD


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FHWA does not . . .

Write AM guidelines for states, et al

Mandate AM regulations (although we certainlyadvise ) as a general rule

Make decisions on new access on interstates(the states do)

Caveat because FHWA oversees Federal funding, we

have a mandated role in reviewing, recommending,and approving some state-sponsored activitiesregarding (mostly) the interstates


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Federal Aid Highway System(Routes eligible for Federal aid)

Interstate System Dwight D. Eisenhower National System of Interstate

Highways

Routes of highest importance

Shall not exceed 43,000 mi.

National Highway System

Shall not exceed 178,250 mi. All routes on the Interstate System are part of NHS

Includes STRAHNET routes


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FHWA Functional

Classification Guidelines

Principal arterials

Minor arterial streets (roads in rural areas)

Collector streets (roads in rural areas)

Local Streets (roads in rural areas)

For Rural, Urban, or Small Urban designations


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TRBs websitewww.accessmanagement.info

Complete proceedings and

prior years too!

Ten principles of AM -- animation


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Introduction to Access 54

Intro to Access Management Principles

Documents

Transcript of Intro to Access Management Principles