HPMS Frequently Asked Questions (FAQ)

Background Questions

  1. What is the NTFA?
  2. What is HPMS?

Question Related to Data Requirements

  1. What data is required?
  2. How often is data required?
  3. What kind of traffic data is required?
  4. What minimal length of count is acceptable?
  5. How should the data be sent in?
  6. What format should the data be sent in?
  7. I have a complete file of all traffic counts collected by my Agency, do I need to separate out only the NTFA data or can I send my complete file?
  8. How do I export traffic count data from RoadSoft?
  9. What is the difference between an ADT and an AADT?
  10. MDOT collecting traffic counts - Outline

Question Related to Road Segmentation

  1. What/Where are the count locations and NTFA segmentation (Traff_ids)?
  2. How are the traff_id/segment Maintained?
  3. What if there are multiple count locations within one NTFA segment?
  4. What if our traffic count program does not collect on all the NTFA segments?

Other Questions

  1. How will I know what is being submitted to the FHWA?
  2. How can I access any counts MDOT has collected?

Basic Background Questions

  • What is the NTFA?

The Non Trunk-line Federal Aid (NTFA) program has been created to meet the additional requirement of FHWA's Highways Performance Monitoring System (HPMS) to obtain a count based Annual Average Daily Traffic (AADT) count on all non trunk line federal aid roads. Federal Highway Administration FHWA also requires, for reporting purposes, that the data be submitted spatially.

  • What is HPMS?

Highways Performance Monitoring System (HPMS)

The HPMS program is a national level highway information system that contains data on the extent, condition, performance, use, and operating characteristics of the nation's highways. This data is used extensively at the federal level in the analysis of highway system condition and performance; but more importantly in the equitable appropriation of Federal Highway dollars and in support of federal efforts to secure increased transportation funding.

U.S. Code of Federal Regulations Title 23 Part 500.203 sets the general requirements for the state's data collection program. It directs that each state develop and implement a Traffic Monitoring System for Highways program on all roads receiving federal funds. MDOT is required to expand the HPMS traffic data collection effort to include all federal aid roads.

Question Related to Data Requirements

  • What data is required?
      1. Count based traffic volume data (Hourly counts, ADTs, or AADT's) on all Federal Aid roads.
      2. The year the traffic data was collected.
      3. Length of count: 24 hr, 48 hr, seven day etc.
      4. Location of the count: Road name and description, or Pr and PR milepoint, or Road name with Latitude and Longitude.
  • How often is data required?

Three or six year cycle based upon the type of road.

      • Three year: Sample, National Highway System (NHS), and Principal Arterials
      • Six year: All non sample road segments that are federal aid eligible are not being collected on the three year count cycle.
  • What kind of traffic data is required?

Sample and NHS: classification count

Principal Arterials and Non Sample: volume count

  • What minimal length of count is acceptable?

24 hours

  • How should the data be sent in?

Data may be sent in either electronically, on disc, or paper.

  • What format should the data be sent in?
      • If you are using RoadSoft to manage your traffic count data, the software does allow you to export a shape file that includes the data required (instructions below).
      • If you are a MS2 user, the software allows you to create an exportable file.
      • If you do not use either of the above, data in about any format you are able to send it is accepted: hand written on a map, excel, dbf, shape files etc. Please contact Melissa Carswell at carswellm@michigan.gov for specifics.
  • I have a complete file of all traffic counts collected by my Agency, do I need to separate out only the NTFA data or can I send my complete file?

AS long as there is location information included the complete file may be sent; the NTFA data will be filtered out and the remaining data can be used to improve the statewide VMT for HPMS.

  • How do I export traffic count data from RoadSoft?

Exporting RoadSoft data:

      1. In RoadSoft, open your map layer
      2. On the left hand side, in point layers, click in the road layer box (it will grey out)
      3. Go to the top left hand corner of screen, right click on file, go down to export. Right click on export, then choose export layer to shape file.
      4. An export layer to shape file screen appears.
      5. Under include, check the following boxes:
        • AADT
        • AADT Year
        • ADT
        • ADT Date
        • BMP
        • EMP
        • NFC
        • Ownership
        • PR_Name
        • PRNO
      6. Click in save export data to and save file.
      7. Click in shapefile name, name file: traffic data.
      8. Click on the export button.

Please indicate the length of time the counts were set for. This can be a summary, i.e. "All counts were set for 24 hours."

  • What is the difference between an ADT and an AADT?

ADT (Average Daily Traffic): The 24 hour average daily traffic.

The total traffic volume during a given time period (more than a day and less than a year) divided by the number of days in that time period.

AADT (Annual Average Daily Traffic): The 24 hour average daily traffic (ADT) to which factors (seasonal, monthly, daily) have been applied.

  • MDOT collecting traffic counts on your roads - outline
    • The NTFA program operates on both three and six year cycles so you will be contacted to coordinate the collection of the NTFA traffic data as the cycles re-occur, corrections are made, or new locations are added.
    • Once the site/count locations in your area have been scheduled, the MDOT field staff assigned to complete the traffic study will notify you minimally one-two weeks prior to setting the traffic monitoring equipment on the roads.
    • The traffic volume counts will be taken with pneumatic tubes and portable traffic counters.
    • Typically the traffic counts will be taken for 48 hours between Monday and Thursday of the week.
    • The traffic data will be processed and will be available on MDOT's Traffic monitoring web site (http://mdotnetpublic.state.mi.us/tmispublic/)normally within six to eight weeks after the data has been collected. M
      Instructions for traversing the website are at located in the Other Questions section of this page.
    • Annually you will receive the Annual Average Daily Traffic (AADT) report of the traffic MDOT collected for your review prior to being sent to the HPMS coordinator for FHWA submittal. The AADT will be created from the 24 hour average of the traffic study using a factor of 1 unless otherwise directed by the Agency. If bad data is identified it will be removed and the location will be scheduled to be re-counted.

Question related to road segmentation

  • What/Where are the Count Locations and NTFA segmentation (Traff_ids)?

The location segmentation of the NTFA Roads is maintained in a GIS environment. In order to minimize the amount of data to be collected, MDOT worked with RPOs/MPOs to group segments of road together by "like traffic patterns" called Traff_ids. The Traff_ids are not limited to one road; a corridor may be made up of multiple roads and multiple PR and PRmlpts.

Traff_id/Segmentation is displayed in either a PDF or a shape file.

  • How are the traff_id/segment maintained?

The Traff_ids/Segments are updated annually due to changes in the Federal Aid Road network. General maintenance of the NTFA segments occurs as errors are identified (segments crossing county lines) or where adjustments should be made to the segmentation (combined or split) to reflect "like traffic patterns" on the federal aid road system. Please review the segmentation and identify any needed changes. I will work with you to correct them.

  • What if there are multiple count locations within one NTFA segment?

If you find you have multiple count locations within one the traff_id segments, you may send data for each of the count sites within the traff_id segment and they will be averaged together or you may average the counts together yourself and send one ADT per segment. If the count data is significantly different from one location to another, dividing the segment into multiple segments may be necessary.

  • What if our traffic count program does not collect on all the NTFA segments?

MDOT staff has been allocated to collect the uncollected. Once the "don't count" locations are identified I will work with you to coordinate MDOT staff collecting on your roads. The data collected will be made available to you. You may also choose to add these count locations to your traffic count program, but it is not required.

Other Questions

  • How will I know what is being submitted to the FHWA?

Annually (March –April) you will receive a copy of the NTFA AADT report for your review and feedback before the report is sent for submittal to FHWA HPMS.

  • How can I access any counts MDOT has collected?

To attain traffic data on roads MDOT has collected, please go to MDOT's Traffic Monitoring Information System (TMIS) site - The site includes hourly short counts, 15 minute short (turning movement) counts, hourly class counts, and AADTs.

    1. Go to http://mdotnetpublic.state.mi.us/tmispublic/
    2. On the left side of this screen click on search Traffic Data.
    3. Fill in the date fields (required) and county and begin your query.
    4. You can be more specific by adding further information (route, PR number, etc), but the dates and county info gets you into the data quickly.
    5. If you are only interested in viewing non-trunk line traffic counts, at the bottom of the screen there is a drop down called Route Designation ( above the search button) choose county roads from this drop down and it will exclude trunk line counts.
    6. The next screen displays what type of counts are available (Short Count Hourly Data, Short Count 15 Min Data ,Traffic Estimates (AADT, DHV etc.)
    7. Clicking on one of these brings you to the count site screen.
    8. Click in the box in front of the count/s you want to review.
    9. Use the gray graph and report buttons to the top of the screen to display the information.
    10. You can print or save the reports by using the icons in the top left corner of the screen.