Minnesota Department of Transportation

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State Aid for Local Transportation

E-Scene February 2021

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MnCMAT2: The Case of the Moving “M” Counties

By: Loren Hill P.E, State Aid Program Support Engineer

When the counties were given their official number many years ago, they were given the number in alphabetic order. However, McLeod was treated as MacLeod in this original assignment. Therefore, McLeod came before Mahnomen, Marshall and Martin. But when the county is sorted in a database, you can see McLeod goes down below Martin. The incorrect table then has Mahnomen (instead of McLeod) with number of 43, etc. The table below illustrates how this occurred.

table

This change in sorting occurred during the great crash data migration of 2016, as part of MnDOT’s move to ERSI Roads and Highways and DPS’s shift to a new crash records and management system. The translational error was limited to Old crashes (pre 2016) while New crashes (2016 to current) crashes were correct.

The bad news is that this resulted in some funky crash mapping. The below figure shows the result from a Mahnomen county crash request. You can see a number of crashes correctly returned in the upper part for Mahnomen County, but also a large number down in McLeod County.

MnCMAT2 screenshot

The good news is all crashes were located in the correct location, just coded to the incorrect county number. A short-term solution was developed and shared with the impacted counties directly and on the MnCMAT2 webpage, while the MnCMAT2 Team worked with our state partners to identify the issue and find a long term solution.

The really good news is that the tables have been fixed with the assistance of the Office of Traffic Engineering (OTE) and Great Arc Technologies (GAT). All crashes now show in the correct county when filtering for that county in MnCMAT2.

If you have any additional questions, please contact Loren Hill at loren.hill@state.mn.us.