Traffic Analysis

DOTD uses an integrated, systematic and performance-based approach to traffic engineering. For our intersection control evaluation policy, please see **EDSM VI.1.1.2 Intersection Control Evaluation (ICE) Requirements.

The following definitions are provided for clarification purposes:

Traffic Signal Upgrade: Work which involves any one of the following for non-emergency purposes; the installation of a new controller and cabinet, rewiring the entire signal, installing all new poles or changing the layout of the signal.
Restricted Crossing U-Turn (RCUT) Intersection: a non-traditional intersection system that utilizes a combination of one partial median opening and two directional median openings. This type of intersection is typically the crossing of major and minor arterials where the left turn moves are relatively high. The openings must be appropriately spaced with one directional U-turn opening or one partial median opening on each side of the partial median opening. The distance between two of these systems is also critical. The intersection and U-turns may be unsignalized or signalized, depending on volumes.
Median U-Turn (MUT) Intersection: the use of two or four directional U-turn openings, placed on each side of an intersection, combined with the prohibition of all left turns at the intersection. This type of intersection is typically the crossing of two major arterials where the through move is heavier than the left turns. All through movements and right turns at the intersection are permitted. The openings must be appropriately spaced with one directional median opening on each side of the partial median opening. The distance between two of these treatments is also critical. The main intersection is typically signalized and the U-turns may be unsignalized or signalized, depending on volumes.
Full Access Traffic Signal: a traffic signal where all approaches are allowed to turn left out and left in.

Traffic Counts/Traffic Monitoring information

All requests must be submitted via email to [email protected]. This includes deliverables, traffic studies, speed studies, plans, permits, scopes, and any other miscellaneous requests.

Click here to register for Traffic Analysis Process and Report Training Classes

This page defines the requirements and expectations for all parties throughout the Traffic Engineering Study Process. The outline below contains links to examples, forms and guides to illustrate specific parts of the study process.

Scope and Man-hour Negotiations (if applicable)

Scope (DOTD)
- Pre-Scope Documentation
- Scope Checklist
- Schedule
Man-hour Spreadsheet with Project Schedule (Consultant)
Signed Contract (Consultant and DOTD)
Notice to Proceed Letter (DOTD)

Kick-Off Meeting

Agenda
Possible Attendees: District Traffic Operations Engineer, Traffic Engineering Management, Consultant, Project Manager, District personnel, Safety section, Environmental section, Road Design section, Bridge Design section, LPA Responsible Charge, local stakeholders and other applicable personnel
Required Documents
- Agenda
- Sign-in Sheet
- Scope
- Project Schedule
- Scope Checklist and all pre-scope documents

Deliverables
- Agenda (submitted to DOTD one week prior to meeting)
- Kickoff Meeting Minutes (submitted to Task Manager within 3 days)

Initial Data Collection

7 Day 24 Hour Counts (48-hr counts with classifications may be used with prior approval)
Peak Period Determination with chart and explanation
Initial Data Collection QA QC Checklist
Deliverables (approval needed to begin Final Collection)
- Appendix A - Initial Data Collection

Final Data Collection

The following should be submitted via digital and hard copy:

Peak Period Counts
- Peak Period Data Collection
  - 48-hr Counts with Classification
  - Turning Movement Counts (TMCs) with Classification and Demand (raw data)
- Peak Hour Determination
  - Driveway and Median Opening Counts (raw data)
- Maps With Raw TMC And Demand For Existing Model
- Volume Check On Aerial
- Maps With Final Peak Hour Volumes (Existing Conditions)
  - Maps With Trip Generation (if applicable)
    - Known developments shall use the latest edition of the ITE Trip Generation Manual
    - Shall be justified, documented and clearly distributed on the network
  - Maps with Balanced Volumes for micro-simulation modeling
    - Map With Recommended Balanced Volumes
    - Map With Final Balanced Volumes
Peak Period Observations
Growth Rate Determination (justification of how the growth rate was determined)
- TransCAD
- Historical Growth
- Any other sources used to obtain growth rate(s)
- Design Year Volume Maps with Growth Rate applied
Speed Study Data – if applicable
- Shall adhere to Section 20.2 of the LADOTD Traffic Engineering Manual
Geometric Field Review
Travel Time Runs (if applicable)
Warrant Analysis (if applicable)
- Summary tables and detailed output
- Shall adhere to MUTCD
Final Collection QA QC Checklist
Deliverables (DOTD approval needed to begin Existing and No-Build Analysis)
- Appendix B - Final Data Collection
- Chapter 1 of Final Report

Existing Safety Analysis

NOTE: This is submitted at the same time as the Existing and No-Build Analysis. Coordinate with **Safety Section to obtain authorization for crash database. Obtain crash history for the three most recently approved years. Analysis must include all crash types, not just vehicles.

**CATScan Tool - used by scope writer for listing of crashes to determine trends and compare to statewide averages
Crash Report Documentation
- Crash History (list of crashes)
- Corrected components of crashes
- Provide individual summary of crash report narratives
Collision Diagram (DOTD will approve year for detailed analysis diagram)
Crash Analysis Summary
- Explain results, patterns, trends and problem areas using results from A, B and C
Existing Safety Analysis QA QC Checklist
Deliverables (needs DOTD approval to begin Alternative Analysis)
- Appendix C - Existing Safety Analysis

Existing and No-Build Analysis

NOTE: Before Existing Analysis begins, software shall be approved. Before No-Build Analysis begins, a design year volume map shall be submitted and approved.

Deliverables for HCM & Vissim Options:
- Appendix D - Existing and No Build Analysis (include electronic files of analyses)
- Tier 1 Analysis (presented at Existing and No Build Results Meeting)
- Chapter 2

Existing and No-Build Analysis (HCM Option)

NOTE: Results of the ENB Analysis determine if Tier 2 Analysis is needed, so feasibility studies and some findings may not move forward. Results may be shared via a phone call if a meeting is unnecessary.

Perform Existing Analysis using approved software (see above section titled Traffic Analysis Tools and Software Resources)
- If oversaturated conditions as defined in the Highway Capacity Manual exist, or if equations do not exist in HCM, then microsimulation should be used. The Traffic Engineering Management Administrator shall approve use of microsimulation.
Perform No-Build Analysis using approved software (see Traffic Analysis Tools and Software Resources)
- A design year volume map shall be submitted and approved prior to No Build Analysis.
Perform a Tier 1 Analysis (for Tier 1 Tools, see Traffic Analysis Tools and Software Resources)
Existing And No Build QA QC Checklist

Existing and No-Build Analysis (Vissim Option)

NOTE: Deliverables at this stage must be approved before Phase 2

Phase 1 - Uncalibrated Microsimulation Model and Document
- Phase 1 QA-QC Checklist
- Phase 1 Meetings
  - Location: DOTD HQ
  - Required Attendees: DOTD HQ Traffic Engineering Section and Consultant
  - Optional Attendees: DOTD Task Managers and other applicable personnel
  - Meeting 1 Content: a presentation discussing the uncalibrated Vissim model and all inputs, calculations, assumptions and QA/QC
  - Meeting 2 Content: discuss and review comments from Meeting 1
Phase 2 - Calibrated Model and Documentation
- Use Louisiana Vissim Calibration Parameters and Vehicles
- Phase 2 QA-QC Checklist
- Calibrated Model (Vissim Modeling Techniques and Guidance)
- Calibration Validation Documentation
- Phase 2 Meeting
  - Location: DOTD HQ
  - Required Attendees: DOTD HQ Traffic Engineering Section and Consultant
  - Optional Attendees: DOTD Task Managers and other applicable personnel
  - Content: discuss calibration comments
Perform Existing and No Build Analysis - see Measures of Effectiveness (MOEs) Document

Perform a Tier 1 Analysis (for Tier 1 Tools, see Traffic Analysis Tools and Software Resources)
Existing And No Build QA QC Checklist

Existing and No-Build Results Meeting

Possible Attendees: District Traffic Operations Engineer, Traffic Engineering Management, Consultant, Project Manager, District personnel, Safety section, Environmental section, Road Design section, Bridge Design section, LPA Responsible Charge, local stakeholders and other applicable personnel
Content:
- Present and discuss Chapter 2: Existing and No Build, including any safety or capacity issues for the study area
- Present and discuss high-level alternatives that address issues found in Chapter 2 (Tier 1 results)
- Discuss tool selection for Alternative Analysis

Deliverables: (Approval needed to begin Preliminary Tier 2 Alternative Analysis)
- Meeting Minutes submitted to Task Manager within 3 days

Preliminary Tier 2 Analysis (if applicable)

High-level analysis
Sketch layouts of the potential alternatives
Redistributed Volumes
Meeting (Optional)
- Possible Attendees: District Traffic Operations Engineer, Traffic Engineering Management, Consultant, Project Manager, District personnel, Safety section, Environmental section, Road Design section, Bridge Design section, LPA Responsible Charge, local stakeholders and other applicable personnel
- Content:
  - Present and discuss single line sketch layouts of the potential alternatives with redistributed volumes and high-level analysis
  - Recommend weight factors and ratings scale for the Alternative Comparative Evaluation Matrix
  - Discuss presentation of results
Deliverables: (Approval needed to begin Final Alternative Analysis)
- Meeting Minutes submitted to Task Manager within 3 days
- High Level Sketches and Analysis
- Redistributed Volumes Map
- Recommended Alternative Comparative Evaluation Matrix

Final Alternative Analysis

Tier 2 Analysis
- If progressing to Tier 3, coordinate Tier 3 Analysis Meeting
- When coordinating with Environmental, may use that matrix if it meets requirements
Tier 3 Analysis (if applicable)
Access Justification Report (AJR) (if applicable)
- Requires the AJR Consultant Checklist
- Must adhere to FHWA Policy on Changes in Access to the Interstate System and address FHWA Policy Points
Alternative Analysis QA/QC Checklist
Deliverable: (Approval needed to begin Final Report)
- Appendix E: Alternative Analysis
- Introduction of Final Report
- Chapter 3 of Final Report
- Executive Summary

Final Alternatives Analysis Meeting

Possible Attendees: District Traffic Operations Engineer, Traffic Engineering Management, Consultant, Project Manager, District personnel, Safety section, Environmental section, Road Design section, Bridge Design section, LPA Responsible Charge, local stakeholders and other applicable personnel
Content: Present and discuss Chapter 3 Final Alternatives
Deliverables: (Approval needed to begin Final Report)
- Meeting Minutes submitted to Task Manager within 3 days

Final Report

Deliverables:
- Sealed Report (Draft must be approved before final submission)
- Minimum 2 Hard Copies
- Minimum 2 electronic copies

DOTD-Approved Traffic Software:

HCS
Sidra
Vissim (only tool allowed for microsimulation)

DOTD uses the HCM (Highway Capacity Manual 6th Edition) for traffic analysis methods and equations. HCS (Highway Capacity Software) will only be allowed for the equations that are in the HCM and cannot be tweaked to provide output for solutions that are not in the HCM. For conditions, limitations or other scenarios that cannot be addressed with HCS, approval shall be obtained before utilizing other software. Using travel time as a measure of effectiveness (MOE) and oversaturation are two examples that need approval to use macroscopic or mesoscopic software.