FM 157 General Findings

• Crash frequency decreasing

• Fewer crashes involving left-turns

• No migration of crashes to intersections

• Very few U-turn crashes

• Crash severity decreasing

• Travel times generally unchanged to small increases

OUTLINE

• INTRODUCTION

• APPLICATIONS

• OBJECTIVES

• METHODOLOGY

• DATA COLLECTION

• DATA ANALYSIS

• STATISTICAL TESTS

• RECOMMENDATIONS AND CONCLUSIONS

OBJECTIVES

1. To conduct a thorough literature review to study the existing methods of computing access density

2. To apply different computational methods of access density and studying their differences

The Values We Used To Craft A Successful Review Process

• Process should be consistent

• Need to involve a multi-disciplinary management level team in each district

• Communication between all parties is critical throughout the process

• Florida DOT staff will use creativity and flexibility to resolve issues

Some Closing Thoughts

• Look for solutions within your organization

• We found a model process in one of our districts.

Why Outreach Matters

• Allows you to…

• Get essential input

• Get in front of the issues

• Deal effectively with potential opponents

• Create opportunities for

  • education

  • and venting!

Lessons learned…

• Define end game- outreach process objectives

• Know your stakeholders!

• Tailor the approach

• Draft a Public Involvement Plan (PIP) before project start-up

Access Spacing and Corner Clearance

• Corner Clearance is the distance provided between a roadway intersection and the nearest access connection

• Corner Clearance is a special case of access connection spacing

No Presentation

What we found

• MDOT is typically getting what they pay for

• Studies/plan preparations take 12 – 18 months

• More than 35 studies completed

• Cost range: $25,000 - $100,000

• Plan/ordinance adoption rates and reasons vary

• Numerous specific recommendations implemented

• MDOT/local government cooperation and coordination typically improves after studies

• Access committees often form in perpetuity

Objective

• Determine the economic effects of access management techniques on businesses adjacent to multilane highways.

In Favor of a Raised Median to Increase Safety?

• Tendency is definitely negative reaction by businesses.

• However, after median installation opinions appear to improve!

Ranking of Customer Considerations

• App. 60% ranked “Accessibility” 4th, 5th, or 6th!

Well-designed Modern Roundabouts enhance the achievement of Access Management principles

• Maintain Integrity of Arterials

• Balance Mobility and Access

• Improve Safety

• Reduce
  Congestion

• Extend the life of
  Infrastructure

Roundabout Operational & Safety Characteristics:

• Driveway and intersection spacing versatility

• Geometric flexibility (properly designed)

• Less queuing

New Mexico’s Goals (2009-10)

• Update and improve current manual, regulations and internal policies.

• Provide training

• Budgeted for phase 1

Switch from Guide to Rules

• Mostly procedures w/o criteria

• All design issues pointed to Green Book

• Not effective program

• Not preserving function or safety

• Lacked ability to address accumulative impacts

• Little criteria to deny a request

Started with

What is Virginia trying to reduce/remove?

• traffic congestion
• dangerous streets & intersections
• new construction
• widening projects

Takeaway #1

• Not all arterials are created equal
  
  • Long distance trips with few access points
  • Local traffic with many access points
• Design speed must be appropriate for the context
• Road should change with the land use

Takeaway #2

II. HSM for Urban Suburban Multilane Streets

• Access Density is a known effect
• Driveways are grouped by type:
  
  • Commercial
  • Institutional
  • Residential
  • Other
• Driveways are either “minor” or “major” if have 50 or more parking spaces

“Lessons Learned”

• The Highway Safety Manual is “Functionally Based”
• The 4D model works acceptably to model 6 lane arterial street

Communication

• The right visual at the right time for the right reason
• + pics

Case Studies

Mitigation in Florida

Case Studies

MY QUESTION:

• Is there a reduction in accidents after access management is implemented?
• If yes, is it statistically significant?

CONCLUSIONS

• Access Management has a significant impact on accident severity and societal costs.
• Access Management results in a significant reduction during PM peak travel
• This knowledge can be helpful when programming future projects.

Themes

• Cities believe in the importance and value of access management
• Access management has to be undertaken hand-in-hand with other municipal considerations
• Access management is one of a handful of tools that should be used for the betterment of the community

Municipal Realities

• Cities are a study in conflicting goals and compromises
• Rarely does one goal trump all others . . . even the safety goal!
• Politics is a daily issue
• Balancing needs is key to success

Conclusions

First Steps

• Updated the existing “median policy”
  
  • no 5 lanes
  • median opening spacing
  • median opening types
• Created “signal spacing and warrant policy”
  
  • established ½ mile spacing
• Created “roundabout policy”
• Policies were signed by the Chief Engineer
  
  • after 2 years are now finally being “tested”

Future

Conclusions & Recommendations

• Effective Temporary Median Treatment
• Construction: Shorter Time and Less Cost
• Safety Effects
• Reduction on Left-Turn Related Crashes
• Total Crashes: Reduced for most of applications except full median closure from bi-directional median opening
• Benefit/Cost Ratio
• Bi-directional Channelization: 8-12
• One-directional Channelization: 3-5

Limitations & Next Step

Project Objectives

• Develop accurate information to communicate types of:
• Safety impacts
• Accident Modification Factors
• Economic impacts

Background

• Frontage roads
  
  • Start two-way (in rural)
• Conversion “pressures”
  
  • Land development
  • Increased traffic volumes, signal operation

Survey Recommendations

Project Objectives

• Develop accurate information to communicate types of:

• Safety impacts

• Accident Modification Factors

• Economic impacts

Background

• Frontage roads

  • Start two-way (in rural)

• Conversion “pressures”

  • Land development

  • Increased traffic volumes, signal operation

Survey Recommendations

• Complete conversions as quickly as possible

Presentation Outline

• Case Study 1-Nebraska Avenue Lane Diet

  • Before: 4-lane undivided

  • After: 2-lane divided with TWLTL

• Case Study 2-Hillsborough Avenue Median Installation

  • Before: 6-lane with TWLTL

  • After: 6-lane with raised medians

Case Study 1: Discussion

• Significant Safety Improvement

• Improvement of all Analyzed Crash Types

• From Worse to Better than SW Average