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ODOT Analysis and Traffic Simulation (OATS) Manual

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OATS Manual Revisions - July 2021

Printed 6/29/2021



Reason for Change

1.1.6 Defined what an "ODOT Project" is Additional information
4.2.1 Revised text to clarify what hours turning movement counts are typically collected to match SHAMM Appendix B Clarification
4.4 Added text stating Queue Lengths must be calculated for AWSC, TWSC, and Roundabout analyses in HCS Additional information
5.9 Added control delay goal.  Additional information Defined different segment types (Basic, Weaving, Overlap). Added additional information for Basic Segment. Additional information When analyzing a signal with actuated control, make sure the “Field-Measured Phase Times” box is unchecked Additional information How to address uncoordinated signalized intersection with optimized cycle lengths less than 60 seconds Additional information Added text stating how to calculate queue length at roundabout using HCS results Additional information
6.6.3 Created new Section, "HCS Facilities Reports" Additional information
7.2 Revised Table 7-4 for Type I Projects Clarification
7.3.2 Added information regarding TransModeler vehicle class distributions. Created Table 7-9A (Vehicle Class Distributions) Calrification/Additional information
8.1.1 Revised Table 8-3 to include v/c for all segments and d/c for Ramp and Freeway segments Additional information

OATS Manual Revisions - January 2021

Printed 1/15/2021



Reason for Change

Table of  contents

Updated Table of Contents,
Figures, and Tables



For TIS, removed "opening year" reference and added "Level 1". Added reference to SHAMM.

Clarification / correction


Removed references to SIDRA

ODOT requires HCS to analyze all roundabouts where it is capable. TransModeler must be used to analyze a roundabout when HCS is incapable.


Added text to emphasize Existing conditions refers to current traffic volumes, geometry, and traffic control.



For minimum study boundary,
removed reference to "urban areas".



Revised Figure 3-2

Updated Figure with smoother, realistic geometry



 Revised "Weaving area" section. Added text to include caseswhere HCS analyzes weave as basic segment, but where the weaving capacity is exceeded.

There are cases where an HCS Weave is determined to not operate as a Weave and is analyzed as a Basic Segment. With heavy weaving volumes, this could give a false perception that the segment is operating better than it really is. For these cases, TransModeler is to be used to verify the operations.


Revised "Mix of intersection traffic control types" section. Replaced "intersections" with "corridors".



Revised Table 4-1. Changed "(Complex Type)" from red text to black text.

Revisions for the January 2021 OATS Manual are in red text. The red text was change to black text because it was not revised


5.7 & 5.9

Clearly stated what the operational goal is for all intersections (AWSC, TWSC, Roundabout, Signalized).

Clarification. The operational goal was only discussed in Section 5.7 (signalized intersections). We want to be clear that the goals apply to all intersection.



 Added text stating what operation goal of mainline is.

Added information


Revised operational requirements at intersections. All v/c's < 1.0 with v/c's < 0.93 preferred.

Revised to match LDM Section 401.2.1

HCS signal optimization. Added "Overall delay" as another option to "Balanced Delay".

There are cases where using the Balanced Delay objective gives unrealistic results. An example could be where one roadway has the majority of the intersection volume.

HCS signal optimization. Revised text regarding minimum number of generations.

Added text to clarify that multiple optimization runs may be required before intersection is optimized.

HCS signal optimization. Added "Cycle Increment = 5s"

Coordinated signalized intersection typically have a cycle increment of 5 seconds.

Added text in Optimization section for coordinated and  uncoordinated signalized intersections.

Using the HCS optimization tool is a new requirement. Traffic analysts that are familiar with ODOT's prior method of analyzing a signalized intersection (i.e. balancing delays) may question the results, especially why a protected left turn phases is less than 7 seconds, or an uncoordinated signalized intersection results in an odd cycle length.

Added text stating how to calculate queue length at roundabout.


Figure 7-39

Updated figure to comply with ODOT's requirements.

 TransModeler simulation parameters at roundabout



Corrected typo, "LOD D" in first group of bullets.



Replaced Table 8-1

Table revised to compare No-Build to Build results.


Reformatted Table 8-2

Changed colors to match Table 8-1.


Added "v/c" in list before Table 8-3. Added distinction between HCS Results (Segments/Facility)




 Revised Table 8-3

Add v/c to HCS Facilities results to provide how a segment is likely to operate, accounting for upstream and downstream bottlenecks. Changed colors to Match Table 8-1.

Scoping Form

Under "Project Traffic Forecasting" section on page 5, removed reference to  attaching Early Coordination Meeting Minutes.

Revised to match OATS Section 1.0