Access Management Principles Presentation
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Contact Information: Neil Spiller at Neil.Spiller@dot.gov
Slide 1. Access Management Principles
Introduction and Overview
FHWA, Washington, D.C.
Slide 2. Presentation
- General overview
- Benefits and Consequences
- Access Management in Practice
- Elements of an AM Program
Slide 3. Part 1
Slide 4. What is "Managing Access"?
Managing and Planning the Spacing and Design of:
Slide 5. Definition of AM
FORMAL: Access management is the programmatic control of the location, spacing, design, and operation of driveways, median openings, interchanges, and street connections to a roadway. (TRB Manual)
INFORMAL: Where the road meets the driveways
Slide 6. Purpose of AM: Balance Mobility vs. Access
Slide 7. A Very Brief History of AM
part 1 of 4
New Jersey 1902 – established "speedways" for horses and bicycles. "No public streets or other highways shall cross or intersect the speedway at grade without consent of the county"
U.S. Supreme Court 1906 – decided that access control along highways was a sovereign power of the states.
Slide 8. A Very Brief History of AM
part 2 of 4
Between 1900 and 1920 the number of automobiles grew from 8K to 10M and lobby groups emerged (e.g., AAA and AASHO)
1919- DDE undertook a transcontinental military convey from D.C. to San Francisco (62 days)
1921 Federal-Aid act established a system of national routes
Slide 9. A Very Brief History of AM
part 3 of 4
In 1920's 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 required permits and reviews as part of their state route adoption plan
By late 1940's almost every state legislated permitting accesses to some degree and court decisions began to confirm that public safety and mobility essentially trumped a landowner's absolute right to access at any point
Slide 10. Basic "right to access"
A property owner has right to have access (i.e., not to be landlocked)
but does NOT have right to expect absolute access at any point,
NOR should they expect compensation for relocated access as long as the government shows justifiable cause and least-impact.
Slide 11. A Very Brief History of AM
part 4 of 4
National standards for individual driveway design were developed in 1960 – AASHO "An Informational Guide for Preparing Private Driveway Regulations for Major Highways"
NCHRP Report 121 (1971) "Protection of Highway Utility" stands as one of the earliest, most recognized discussions of access control
Beginning of modern AM – credited to Colorado, 1979, when they created 1st comprehensive principals of AM and spelled out the safety, aesthetic and delay-reducing benefits of AM "incorporated" into statute
Slide 12. Colorado, 1979
"The lack of adequate access management on the highway system and the proliferation of driveways and other access approaches is a major contributor to highway accidents and the greatest single factor behind the functional deterioration of highways in this state. As new accesses are constructed and signals erected, the speeds and capacity of the roadways decrease, and congestion challenges to the motorist increase."
-- Colorado State Highway Access Code
Slide 13. National Perspective
- "The lack of access control along arterial highways has been the largest single factor contributing to the obsolescence of highway facilities"
NCHRP Report 121 Protection of Highway Utility
- "Every study since the 1940’s has indicated a direct and significant link between access frequency and accidents"
International R/W Assoc. conference paper, 1999
Slide 14. Part 2
Benefits and Consequences
Driveways are inevitable and necessary but as their numbers go up, so too does the propensity for accidents in that corridor.
Slide 16. Benefits of AM
- Preserve integrity of the roadway system
- Improve safety and capacity
- Extend functional life 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)
Slide 17. Groups Who Benefit
Which groups will benefit from good AM?
- Business Owners
Slide 18. % of Driveway Crashes by Movement
Here's a scoop!
The majority of access-related crashes involve LT's (63%)
Slide 19. Composite Crash Rate Indices
Crash rate indices increase as # of access points per mile increases
Slide 20. AM in the Transportation and Land Use Cycle
Slide 21. What’s the bottom line?
Over-arching Goal of AM:
Limit the number and impact of driver decision and conflict points from impacting on through traffic.
Slide 22. Traffic Conflict
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, they create chaos, and it is difficult to avoid one at the cost of another.
Slide 23. Conflict Points
Each access point creates potential conflicts between through traffic and turning traffic.
Slide 24. Conflicts
(and don't forget pedestrian and bicycle movements too!)
Slide 25. 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
Slide 26. Effect of Speed Differential to Propensity for Crashes
Slide 27. How to improve "Consequences"
- Unclutter the corridor ("Pruning")
Direct where driveways are best suited
- "Assign" turn movements by defining and separating them
- Develop guidelines for property access, thru traffic, and hierarchy of streets
- Enforce against violations and poor practices in siting driveways and streets
Slide 28. Part 3
Access Management in Practice
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" through movements
Slide 30. Driveway Bypass Lane
Where restricted from placing a median, can you install a bypass lane?
Slide 31. Median Redesign
- Increased separation between intersections
- Introduction of U-turns to replace former movements
Slide 32. Results—Fewer accidents on 'Managed' roads
Source: "Colorado Access Control Demonstration Project" – 1985
Slide 33. Results—Higher 'thru' speeds on 'Managed' roads
Effects of Access Management on travel speeds in the P.M. peak hour
Slide 34. Signal Spacing Variables
- "Tweak" these . . .
- Intersection spacing
- Overall cycle lengths
- Cycle phasing
- To “Seek” these . . .
- Progression speed
- Progression efficiency
Slide 35. Relationship between cycle length, signal spacing, and speed
Slide 36. What methods are used?
- Permits, legislation and corridor planning
- Auxiliary lanes
- Signals and signal spacing
- Driveway location, spacing, and design
- Corner clearance
- Cross-access and joint access
- Frontage roads and connectors
Slide 37. Who is Responsible for AM?
Professionals that guide urban development
- Approval agents (Boards, Councils, etc.)
- Land use attorneys
- Agency staff
- Citizens, motorists
- Property Owners
- Ad-hoc groups (pedestrians, bicycles, social change)
Slide 38. What is "Functional Intersection Area" and why is this important?
The influence area associated with a driveway includes
- The impact length (distance back at which cars begin to be affected)
- Perception-reaction distance
- And the "car length"
Upstream length > Downstream length
Slide 39.Functional Intersection Area
The upstream and downstream areas of influence that affect driver decision. Note that 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?
Slide 40. Application of 'Access Window'
Slide 41. Different types of Access Controls
- "Police" power
- Eminent domain
- Statutes and statutory designation
Slide 42. In plain English?!
An agency uses eminent domain to purchase or "take" the right of access.
An agency uses their police power to approve or deny the application for a driveway and impart public safety
Slide 43. Part 4
Elements of an AM Program
Slide 44. Elements of an AM Program
- 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
Slide 45. Every stakeholder needs to be "on board" with the plan and aware of the consequences of, and need for, guidance, structure and goal
||Mayor, Council, Board
||Motorists and property owners
||Quality of effort and wins / losses
||Improved traffic progression, safety
Slide 46. Have a plan — stick to it!
Slide 47. 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 be considered
- Other stakeholders? Adjacent/abutting property owners? Public?
Slide 48. Traffic Impact Study Areas
Slide 49. FHWA's Role
- To champion the role that AM serves in improving 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)
"Benefits of Access Management" Tri-fold
AM Resource DVD
Public Meeting Handout and CD
Slide 50. FHWA does not . . .
- Write AM guidelines for states, et al
- Mandate AM regulations (although we certainly "advise") 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 activities regarding (mostly) the interstates
Slide 51. 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
Slide 52. FHWA Functional Classification Guidelines
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
Slide 53. TRB's website
Slide 54. Managed Access Success!