Traffic Monitoring Program

Trunkline roads consist of interstates, US routes, M routes and any other federal aid-eligible roads that fall under the jurisdiction of the Michigan Department of Transportation (MDOT). These are generally Functional Classification 1 and 2 roads and include ramps. MDOT conducts all traffic counts that occur on trunkline roads for Highway Performance Monitoring System (HPMS) reporting.

Non-trunkline roads consist of all federal aid-eligible roads that are under the jurisdiction of local agencies such as county road commissions, townships, cities, and villages. These are generally Functional Class 3-5 roads and include Urban Functional Class 6 roads. MDOT coordinates with transportation management areas (TMAs), metropolitan planning organizations (MPOs), and the local agencies across the state to conduct our own traffic counts and gather traffic count data collected by local agencies on non-trunkline roads for HPMS reporting.

Local roads consist of federal aid-eligible roads that are under the jurisdiction of local agencies. These are Functional Class 7 roads and include Rural Functional Class 6 roads. MDOT is in the early stages of coordinating with local agencies to conduct our own traffic counts on these roads, but generally rely on local agencies to collect and supply traffic count data on local roads for HPMS reporting.

The Highway Performance Monitoring System (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 each state to 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.

• Count based traffic volume data (hourly counts, average daily traffic [ADTs], or annual average daily traffic [AADTs]) on all federal-aid roads.
• The year the traffic data was collected.
• Length of count: 24-hour, 48-hour, seven-day etc.
• Location of the count: Road name and description, or physical road (PR) and PR mile point, or road name with latitude and longitude.

Three or six-year cycle based upon the type of road:

• Three-year: National Highway System (NHS) and principal arterials.
• Six-year: HPMS sample road segments and any other federal aid-eligible roads that are not NHS or principal arterials.

• Sample and NHS: Classification count.
• Principal arterials and non-sample: Volume count.

24 hours.

Data may be submitted electronically (multiple formats supported), manual upload to MDOT's Traffic Database Management System (TDMS), or a digital data transfer (if supported).

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 ADT to which factors (seasonal, monthly, daily) have been applied.

MDOT worked with regional planning organizations (RPOs) and MPOs to group segments with similar traffic patterns to form traffic segments. The traffic segments are based on traffic patterns and not on routes, functional classification, or PR. Traffic segments are updated throughout the year using ESRI's Roads and Highways platform to incorporate appropriate segment changes. On an annual basis, the traffic segments are reviewed for data integrity and accuracy of grouped traffic patterns. The traffic segmentation is maintained in a geographic information system (GIS) environment, Roads and Highways, hosted by ESRI.

MDOT staff has been allocated to collect the uncollected. Once the "don't count" locations are identified we 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.

The AADT map is an ArcGIS web-map that displays MDOT AADT and Commercial Annual Average Daily Traffic (CAADT) (including single unit and combo unit AADTs) information. In contrast to the point-based data available in MDOT’s TDMS, the AADT/CAADT information in the AADT map is based on MDOT’s traffic segmentation network. MDOT maintains AADT/CAADT information for the most recent three years and the data can be downloaded from the AADT map itself or by visiting MDOT’s GIS Open Data Portal (also has data prior to the most recent three years).

The end date for the HPMS submittal to the FHWA is June 15. MDOT finalizes the previous year data at the end of summer/early fall. This timeline is dependent on the approval from FHWA of MDOT's HPMS submittal. Once the data is finalized, it is made publicly available through FHWA's website or a variety of online publications hosted by MDOT (web maps and data portals).

The traffic counts that come from outside agencies are uploaded into MDOT's TDMS system and are pushed through MDOT's quality assurance/quality control (QA/QC) process. All approved counts will be used for MDOT's annual submittal.

Traffic counts are stored at traffic stations in MDOT's TDMS as point-based data. To attain traffic data that either MDOT has collected or has received from other collecting agencies, please go to MDOT's Traffic Monitoring Program webpage. This site includes a brief overview of MDOT's traffic collection programs and provides all the necessary resources to view, print or download all the traffic data MDOT has available. In addition, documentation is also provided for navigating MDOT's traffic data.

Nonmotorized counts are conducted on an annual basis throughout the entire state of Michigan on many different facilities. Count locations are determined by internal stakeholders and count requests via MDOT’s 1485 Nonmotorized Traffic Survey form. Most nonmotorized counts run for 48 hours but can be as long as one week (see the 1485 form for all durations of counts and on what facilities MDOT can collect on).

Nonmotorized traffic data can only be found in the Nonmotorized Database System at this time, a sub-database of TDMS. The data is stored at nonmotorized traffic station and is point-based, like in TDMS.