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REVISION REQUEST 4191

902.4.1 General (MUTCD Section 4D.01)

Support. The features of traffic control signals of interest to road users are the location, design, and meaning of the signal indications. Uniformity in the design features that affect the traffic to be controlled, as set forth in this Manual, is especially important for the safety and efficiency of operations.

Traffic control signals can be operated in pretimed, semi-actuated, or full-actuated modes. For isolated (non-interconnected) signalized locations on rural high-speed highways, full-actuated mode with advance vehicle detection on the high-speed approaches is typically used. These features are designed to reduce the frequency with which the onset of the yellow change interval is displayed when high-speed approaching vehicles are in the “dilemma zone” such that the drivers of these high-speed vehicles find it difficult to decide whether to stop or proceed.

EPG 902.23.1 contains information regarding traffic control signal operation.

Standard. The design and operation of traffic control signals shall take into consideration the needs of all modes of traffic including access and safety.

When a traffic control signal is not in operation, such as before it is placed in service, during seasonal shutdowns, or when it is not desirable to operate the traffic control signal, the signal heads shall be covered, turned, or taken down to clearly indicate that the traffic control signal is not in operation.

If a traffic control signal head is not in operation and has a yellow retroreflective strip along the perimeter of its signal backplate (see the fifth option paragraph of EPG 902.4.6), the signal head, shall be covered. If a cover is placed over a traffic control signal head that is not in operation, the entire signal head, including the signal faces and backplate shall be covered.

Standard. A traffic control signal shall control traffic only at the intersection or midblock location where the signal faces are placed.

Guidance. Midblock crosswalks should not be signalized if they are located within 1,000 feet from the nearest traffic control signal, unless supported by an engineering study or engineering judgment that indicates safe and efficient operation of the closely-spaced traffic control signals can be achieved.

Midblock crosswalks should not be signalized if they are located within 100 feet from side streets or driveways that are controlled by STOP signs or YIELD signs, unless supported by an engineering study or engineering judgment that considers restricting turning movements from the side street or driveway to eliminate conflicts with pedestrian and bicyclist movements.

Engineering judgment should be used to determine the proper phasing and timing for a traffic control signal. Since traffic flows and patterns change, phasing and timing should be reevaluated regularly and updated if needed.

Traffic control signals within ½ mile of one another along a major route or in a network of intersecting major routes should be coordinated, preferably with interconnected controller units. Where traffic control signals that are within ½ mile of one another along a major route have a jurisdictional boundary or a boundary between different signal systems between them, coordination across the boundary should be considered.

Support. Signal coordination need not be maintained between control sections that operate on different cycle lengths.

EPG 902.6.19 and EPG 913.4.9 contain information about coordination of traffic control signals with grade crossing signals.







REVISION REQUEST 4202

236.5.29 License Plate Readers

Automated License Plate Readers (LPRs) and Pan-Tilt-Zoom cameras (PTZs) are an increasingly popular way for law enforcement to better locate vehicles associated with criminal activity. The deployment of these devices on Commission right of way require FHWA approval and shall not create a safety risk for the traveling public or interfere with MoDOT’s ability to maintain and operate the transportation system.

The general process for LPR and PTZ requests is outlined in EPG 941.10.

It is the requesting law enforcement agency’s responsibility to contact MoDOT’s local traffic permit specialist to initiate the permitting process, after approval from Department of Public Safety (DPS) has been received. The local district traffic representative will work with the applicant through the permitting process.

Once the district traffic staff determine the LPRs or PTZs are eligible to be deployed on Commission right of way, the district traffic staff will forward the drafted permit via the permit database to Central Office Right of Way (COROW). CO ROW will then gather the following items to seek FHWA approval:

Once COROW gathers the items listed above, they will include the following items in their submittal to FHWA for approval:

Upon receiving FHWA approval, COROW will upload the FHWA approval documentation in the permit database and notify the district traffic staff they may proceed with issuing the permit. If FHWA does not approve, the permit cannot be issued.








941.10 Automated License Plate Readers and Pan-Tilt-Zoom Cameras

Additional Resources
License Plate Readers SharePoint Site (MoDOT Access Only)
LPR Flowchart and Installation Locations
General LPR Typical Details
Flock LPR Typical Details.

Automated License Plate Readers (LPRs) and Pan-Tilt-Zoom cameras (PTZs) are an increasingly popular way for law enforcement to better locate vehicles associated with criminal activity. These high-tech devices allow law enforcement agencies to compare plate numbers against those of stolen vehicles and vehicles driven by individuals with expired licenses, an active warrant, or involved with terrorist activities.

The deployment of these devices on Commission right of way shall not create a safety risk for the traveling public or interfere with MoDOT’s ability to maintain and operate the transportation system. All costs associated with the installation and maintenance of the LPRs and PTZs will be the responsibility of the applicant. The following guidance applies to any LPR or PTZ installed on Commission right of way.

941.10.1 Approval Process

The general process for LPR and PTZ requests are outlined in the LPR Flowchart. Law enforcement agencies must request approval, in writing, for deploying LPRs and PTZs from the Director of the Department of Public Safety. Requests are to be on the law enforcement agency letterhead and emailed to the Department of Public Safety at dpsinfo@dps.mo.gov.

The Department of Public Safety (DPS) provides approval for the use of LPR and PTZ devices. MoDOT only facilitates the administration of work by others on Commission right of way. MoDOT’s permitting process will be followed for the constructability and maintenance of the devices to ensure the safety of the traveling public. If an issue is identified through our normal permitting process and cannot be resolved, a permit for this work will not be issued.

It is the requesting law enforcement agency’s responsibility to contact MoDOT’s local permit specialist to initiate the permitting process, after approval from DPS has been received. Contact information for MoDOT’s local permit specialists can be found using the District Permit Maps.

The local district traffic representative will work with the applicant through the permitting process. The permit request submittal must include:

  • An aerial image, or map, depicting all the individual LPR locations included in the submittal.
  • An aerial image for each LPR location included in the submittal clearly showing where the proposed installation with respect to the roadway and other structures on the right of way.
  • A set of drawings, or plans, showing the hardware and their installation details proposed on the right of way, which must be signed and sealed by a Missouri Professional Engineer (P.E.).
  • This applies to stand alone installations as well as installations on approved existing structures on right of way, such as signal and sign truss uprights.
  • Executing a Roles and Responsibilities document to specifically address the expectations of maintaining the devices being installed.
  • A plan to provide electricity to the equipment as well as retrieving data from the equipment.
  • A traffic control plan for any proposed work on the right of way to notify and guide motorists safely through the activity area.
  • A surety deposit or performance bond to insure satisfactory work, accepted by MoDOT.

A separate permit may be provided for the applicant, or their consultant, to access the right of way to collect information needed to develop a set of plans for installing the devices.






941.10.2 Location

When receiving a request, the district traffic staff will work with the law enforcement agency to determine if there are acceptable locations for the proposed installations off MoDOT right of way. If there are no appropriate locations off of right of way, the district traffic staff will work with the agency to determine if the LPRs and PTZs requested can be deployed on Commission right of way.

LPR and PTZ installations on Commission right of way shall only monitor traffic on MoDOT roadways and shall not be used to monitor off system roadways, such as county, city, or private facilities.

Once the district traffic staff determine the LPRs or PTZs are eligible to be deployed on Commission right of way, the district traffic staff will forward the drafted permit via the permit database to Central Office Right of Way (COROW). See section 236.5.29 for COROW’s review and process for requesting FHWA’s approval.

Upon receiving FHWA approval, COROW will upload the FHWA approval documentation in the permit database and notify the district traffic staff they may proceed with issuing the permit. If FHWA does not approve, the permit cannot be issued.

941.10.2.1 LPR and PTZ Non-Permanent Installations - Speed Enforcement Trailers

The only form of non-permanent structure that LPR and PTZ devices may be deployed on, when placed on Commission right of way, are speed trailers. However, speed trailers shall only be deployed for the primary purpose of speed enforcement and not for the primary purpose of deploying LPR and PTZ devices. When speed trailers are deployed, the electronic speed message must be active and the unit deployed and delineated in accordance with EPG 907.8 Speed Trailers Deployed by Others.

941.10.2.2 LPR and PTZ Permanent Installations

To ensure LPR and PTZ devices do not represent an added risk to the traveling public, there are defined installation locations which are acceptable on Commission right of way. Acceptable installation locations include:

  • Only deployed on the right side of the roadway outside of the shoulder.
  • On MoDOT traffic signal upright poles, except in instances where deployment will interfere with other devices already attached to the pole.
  • On MoDOT overhead sign truss upright poles.
  • On any non-breakaway structure owned by a third party, with the written permission of the third party.
  • On independent support behind barrier (installed and maintained by requesting agency or their LPR vendor) in accordance with the guidance in EPG 941.10.2.2.3.
  • On independent breakaway support that has been crash tested by the LPR vendor and approved by MoDOT. See EPG 941.10.2.2.3 for approved systems.

Locations where LPR and PTZ devices shall not be installed include, but are not limited to:

  • Any installation in the median / left side of a divided highway.
  • Any overhead location.
  • On any existing structure on right of way which has a breakaway design, whether it is owned by the Commission or a third party.
  • Any bridge structure.
  • Any location that already has a device installed.
  • Any location that may interfere with MoDOT's ability to manage the transportation system.

MoDOT does not allow the deployment of LPR and PTZ devices overhead or in the median as these locations would result in increased impact on the safety and mobility of the traveling public when performing installation and maintenance activities. LPR and PTZ devices are not permitted on any existing structure which is designed as a breakaway device on Commission right of way, regardless of ownership, as the addition of these devices could negatively impact the performance and safety of the breakaway structure.

There are three methods identified for deploying LPR and PTZ devices on Commission right of way, all of which must be approved by MoDOT and installed under a MoDOT permit:

  • LPRs and PTZs installed on MoDOT structures.
  • LPRs and PTZs installed on non-MoDOT structures.
  • LPRs and PTZs installed on new stand-alone structures.
941.10.2.2.1 LPRs and PTZs Installed on MoDOT Structures

LPRs and PTZs can be attached to MoDOT’s existing traffic signal upright poles and existing sign truss upright poles upon review and approval by MoDOT.

  • Green Box Indicates Acceptable Mounting Location on a
    Traffic Signal, Red Boxes are Unacceptable Mounting Locations
  • Green Box Indicates Acceptable Mounting Location on an Overhead Sign Truss,
    Red Boxes are Unacceptable Mounting Locations
    • 941.10.2.2.2 LPRs and PTZs Installed on non-MoDOT Structures

    There are some structures that have been permitted on Commission right of way which are owned by other entities, such as structures for weigh station bypass equipment or utility poles. Law enforcement agencies have the option to acquire approval from the owners of the structures to utilize them as supports for their LPR and PTZ devices if they meet the following criteria:

    • The structure must be reviewed and approved by MoDOT for use.
    • Written permission from the owner of the structure must be acquired and supplied to MoDOT.
    • Any structure which is of a breakaway design, such as roadway lighting poles or highway signs, are not acceptable support structures.
    • Installation location criteria listed in EPG 941.10.2.2 also apply to these structures.
    941.10.2.2.3 LPRs and PTZs Installed on New Stand-Alone Structures

    To limit the number of structures on Commission right of way, opportunities to locate the LPRs and PTZs off of right of way is the preferred option, followed by an installation location on an existing structure already on right of way. If it is determined a new stand-alone structure is required to facilitate the LPR and PTZ deployment, the following guidance shall be followed:

    • The district traffic shall work with the local agency to find a location which meets the requirements outlined on the General LPR Typical Details or Flock LPR Typical Details.
    • Stand-Alone LPR and PTZ structures shall be properly spaced away from other traffic control devices, which can include but are not limited to highway signs, traffic signal, roadway lighting poles, etc.:
    ○ No closer than 200 feet upstream of a traffic control device.
    ○ No closer than 50 feet downstream of a traffic control device.
    • Installation and maintenance access should be via adjacent private property or secondary roadways for divided highway, unless physically impossible.






    REVISION REQUEST 4223

    New Test Method

    106.3.2.100 TM-100, Procedure to Calculate the Slope Ratio (SR) and Stripping Inflection Point (SIP) using the Hamburg Wheel-Track (HWT) Test

    1. Run the HWT test in accordance with AASHTO T 324 at 50 +/- 1 º C for 20,000 passes (regardless of the mix type and contract binder grade).

    Record rut depth at each cycle or at regular cycle intervals during the test.

    2. Plot the average rut depth versus number of cycles up to the 20,000 passes.

    Create a graph using Hamburg Test Data Analysis form that is available at MoDOT’s “Forms for Contractor Use” page on MoDOT’s website.

    • X-axis: number of wheel passes or cycles.
    • Y-axis: rut depth in millimeters.
    • Report the average rut depth at 20,000 passes for all asphalt mixtures:
    Binder Contract Grade Minimum Wheel Passes Maximum Rut Depth (mm)
    58-28H / 64-22 20,000 20,000 4 mm
    64-22H / 70-22
    64-22V / 76-22
    • If the average rut depth at 20,000 passes is 4 mm or less, the mixture passes the HWT stripping test and no further analysis is needed. If the rut depth exceeds 4mm, continue with Steps 3 through 5.

    3. Identify the two linear portions of the curve.

    Determine the two best-fit straight-line sections using a linear regression equation from excel spreadsheet or other graphing tools:

    • First portion: steady-state rutting region before stripping begins.
    • Second portion: post-stripping region where rutting increases more rapidly.

    4. Calculate the slope of each portion.

    Use linear regression for each section:

    • Slope 1 = slope of the first portion – Creep Slope (M1) from linear regression equation – y = M1x+ b1.
    • Slope 2 = slope of the second portion – Striping Slope (M2) from linear regression equation – y2 = M2x + b2.

    5. Calculate the slope ratio.

    Slope Ratio = M2 ÷ M1

    Where:

    • M1 = slope of the steady-state rutting portion.
    • M2 = slope of the stripping portion.
    • If slope ration (M2 / M1) is less than 2.0 from the two linear equations from the creep slope and stripping slope for 20,000 passes using HWT test, the mixture passes the HWT stripping test and no further analysis is needed. If the slope ration (M2 / M1) is 2.0 or greater, continue with Step 6.

    6. Calculate the stripping inflection point.

    Find the intersection of the two best-fit lines using linear regression equations determined from Steps 3 through 5.

    If the first line is:
    y = M1x + b1

    and the second line is:
    y = M2x + b2

    then:
    SIP = (b2 - b1) ÷ (M1 - M2)

    Where:

    • b1 = intercept of the first portion.
    • b2 = intercept of the second portion.
    • M1 = slope of the first portion.
    • M2 = slope of the second portion.
    If the stripping inflection point (SIP) is greater than 15,000 wheel passes, then the mixture passes the HWT stripping test and no further analysis is needed.

    7. Interpret the Combined HWT Stripping Results.

    • A higher SIP generally indicates better resistance to moisture damage.
    • A lower slope ratio usually indicates less acceleration in rutting after stripping begins.
    • If no second slope is evident, the mix may not have shown stripping during the test.
    • If the SIP is 15,000 wheel passes or less, did not pass the 4 mm rut depth in Step 2, and did not pass the slope ratio (SR) of less than 2.0 in Steps 3 through 5, the mixture is unacceptable.

    EXAMPLE HWT Report:

    Rut depth at 20,000 Passes = 16.3 mm

    Slope Ratio = M2/M1 = -0.0014893 / -0.00015636 = 9.52

    SIP = = (b2 - b1) ÷ (M1 - M2) =

    b2 = ((-0.0014893*-17849))+(-13.5956) = 12.9869157
    b1 = ((0.00015636*-3067))+(-1.8183) = -1.33874388

    SIP = ((12.9869157 – (-1.33874388)) / ((-0.00015636) – (-0.0014893)) = 10,747

    With rutting greater than 4 mm, Slope Ratio greater than 2.0, and SIP less than 15,000, this mixture did not pass the HWT stripping criteria and is rutting susceptible.

    8. Report the results.

    Include the following in the final report:

    • Contract ID, Project Number, Mix Identification.
    • Confirm HWT Equipment meets AASHTO T 324.
    • Confirm Test temperature = 50ºC.
    • Confirm Number of cycles completed = 20,000 Passes.
    • Report Total Average Rut Depth at 20,000 Passes.
    • Establish Rut depth curves.
    • Provide equations for Creep Slope Best Fit Line and Stripping Slope Best Fit Line using Linear regression methods in excel or other programs.
    • Report the Slope Ratio.
    • Report the Stripping Inflection Point.
    • Report the parameters that the asphalt mixture meets using the table below. When one parameter passes, the other parameters may be omitted.
    Parameter Stripping Criteria Pass or Fail?
    Total Rut Depth Less Than or Equal to 4 mm
    Slope Ratio (SR) Less Than 2.0
    Stripping Inflection Point (SIP) Greater Than 15,000 Passes

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    REVISION REQUEST 4224

    This test method establishes the procedures for identifying potential alkali carbonate reactivity (expansion) and acceptance of aggregate used in concrete pavements and masonry. This test method applies to new quarries, new ledges (and combinations of ledges), existing quarries and ledges.

    106.3.2.93.1 Means of Evaluating Aggregate Alkali Carbonate Reactivity

    1. Chemical Analysis

    The chemical analysis of aggregate reactivity is an objective, quantifiable and repeatable test. MoDOT will perform the chemical analysis per the process identified in ASTM C 25 for determining the aggregate composition. The analysis determines the calcium oxide (CaO), magnesium oxide (MgO), and aluminum oxide (Al2O3) content of the aggregate. The chemical compositions are then plotted on a chart with the CaO/MgO ratio on the y-axis and Al2O3 percentage on the x-axis per Fig. 2 in AASHTO R 80. Aggregates are considered potentially reactive if the Al2O3 content is greater than or equal to 1.0% and the CaO/MgO ratio is either greater than or equal to 3.0 or less than or equal to 10.0 (see chart below). See flow charts in 106.3.2.93.2 for approval process.

    * MoDOT’s upper and lower limits of potentially reactive (shaded area) aggregates.

    2. Petrographic Examination

    A petrographic examination is another means of determining alkali carbonate reactivity. The sample aggregate for petrographic analysis will be obtained at the same time as the source sample. MoDOT personnel shall be present at the time of sample. The petrographic sample shall be placed in an approved tamper-evident container (provided by the quarry) for shipment to petrographer. Per ASTM C 295, a petrographic examination is to be performed by a petrographer with at least 5 years of experience in petrographic examinations of concrete aggregate including, but not limited to, identification of minerals in aggregate, classification of rock types, and categorizing physical and chemical properties of rocks and minerals. The petrographer will have completed college level course work in mineralogy, petrography, or optical mineralogy. MoDOT does not accept on-the-job training by a non-degreed petrographer as qualified to perform petrographic examinations. MoDOT may request petrographer’s qualifications in addition to the petrographic report. The procedures in C 295 shall be used to perform the petrographic examination. The petrographic examination report to MoDOT shall include at a minimum:

    • Quarry name and ledge name; all ledges if used in combination
    • MoDOT District where quarry resides
    • Date sample was obtained; date petrographic analysis was completed
    • Name of petrographer and company/organization affiliated
    • Lithographic descriptions with photographs of the sample(s) examined
    • Microphotographs of aggregate indicating carbonate particles and/or other reactive materials
    • Results of the examination
    • All conclusions related to the examination

    See flow charts in EPG 106.3.2.93.2 for the approval process. See EPG 106.3.2.93.3 for petrographic examination submittals. No direct payment will be made by the Commission for shipping the petrographic analysis sample to petrographer, or for the petrographic analysis performed by the petrographer.

    3. Concrete Prism/Beam Test

    ASTM C 1105 is yet another means for determining the potential expansion of alkali carbonate reactivity in concrete aggregate. MoDOT will perform this test per C 1105 at its Central Laboratory. Concrete specimen expansion will be measured at 3, 6, 9, and 12 months. The test specimens will be considered alkali carbonate reactive (expansive) if the specimens expand greater than 0.030% at 12 months. See flow chart in EPG 106.3.2.93.2 for the approval process.

    106.3.2.93.2 Approval Process for Potential Alkali Carbonate Reactive Aggregate

    1. Process for New Ledges and New Quarries The flowchart shown in Figure 1 shows the process for determining alkali carbonate reactivity (expansiveness) in new ledges and quarries. It is important to note TM-93 is only for determining whether or not aggregate is potentially expansive. All other requirements of Sec. 1005 shall be met for the ledge(s) to be approved for use in pavement or masonry concrete.

    Should ASTM C 1105 test method need to be performed on the aggregate, the quarry will be notified by District personnel that this test method requires 12 months to complete, and approval of aggregate during those 12 months will be provisionally granted based on physical test results. Final approval will be determined upon completion of ASTM C 1105. Aggregate that fails to meet the expansion limit of 0.030% cannot be approved for use in pavement or masonry concrete. The aggregate however, can be considered for other uses based on meeting required specifications.

    Figure 1. Process for determining alkali carbonate reactivity for new ledges and quarries.

    2. Process for Existing Ledges and Existing Quarries

    The flowchart shown in Figure 2 shows the process for determining alkali carbonate reactivity (expansiveness) in existing ledges and quarries. It is important to note TM-93 is only for determining whether or not aggregate is potentially expansive. All other requirements of Sec. 1005 shall be met before the ledge(s) are approved for use in pavement or masonry concrete.

    Should ASTM C 1105 test method need to be performed on the aggregate, the quarry will be notified by District personnel that this test method requires 12 months to complete, and approval of aggregate during those 12 months will be provisionally granted based on physical test results. Final approval will be determined upon completion of ASTM C 1105. Aggregate that fails to meet the expansion limit of 0.030% cannot be approved for use in pavement or masonry concrete. The aggregate however, can be considered for other uses based on meeting required specifications.

    Figure 2. Process for determining alkali carbonate reactivity for existing ledges and quarries.

    106.3.2.93.3 Submitting Petrographic Examinations Reports to MoDOT

    1. Petrographic Examination Reports

    Petrographic examination reports can be used in the process to determine the alkali carbonate reactivity (expansiveness) of aggregate. See petrographer requirements in Section 109.3.2.93.1. When a quarry obtains a petrographic examination report, the report shall be submitted to the District Construction and Materials Department of the district the quarry resides. The submittal can be made electronically or can be an original hard copy mailed/delivered to the district. Hard copy reports will be scanned/digitized for easier file storage. Regardless of whether or not the petrographic examination report shows the aggregate is potentially expansive, MoDOT will retain the report. The district will forward the report to Central Office Construction and Materials Division for document retention. This will allow time to prepare for ASTM C 1105 testing if necessary.

    All petrographic reports will be digitally stored by Central Office Construction and Materials Division.


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