interactive visualization icon

Explore CMV-involved fatalities in North Carolina with our data visualization tool.

Interactively filter for crash severity, date, time, and location   •   Time of day / day of week heat grid   •   Locations of crashes (counties and points)

For help understanding the terms and concepts in the visualization, please see the FAQ below the visualization or email

* Crash data depicted on the Coverlab website is intended to provide the public with general overview of traffic safety trends, should not be used for planning purposes, and is not considered authoritative. Any questions regarding specifics of crash data accuracy, frequencies, location, etc., should be directed to NCDOT. Data Source: NCDOT Traffic Engineering Accident Analysis System (TEAAS)


What is a CMV?

A CMV (Commercial Motor Vehicle) is any motorized vehicle whose main purpose is to conduct commercial operations. For this visualization, a CMV includes:

  • Commercial Bus
  • Single Unit Truck (2-Axle, 6-Tire)
  • Single Unit Truck (3 Or More Axles)
  • Tractor/Doubles
  • Tractor/Semi-Trailer
  • Truck/Trailer
  • Unknown Heavy Truck

It may be important to know that “commercial vehicle” is defined differently depending on which state, federal, or independent agency you speak with.

What does clicking in the visualization do? How does the interaction work?

When you click on an item of data in the visualization, such as a bar, square, county, number, etc, it will filter the rest of the charts with that data item. For example, if you click on Wake county in the map, all the other charts will update and show data for Wake county.

To turn off this interactive filtering, simply click on the data item you clicked on. For example, if you had clicked on Wake county and wish to turn it off, simply click on Wake county again.

The two grids in the visualization can also be sorted. Clicking on a row or column will filter (the same way clicking on Wake county in the example above), but if you hover over the name you will see a tiny bar-chart-icon. Clicking on that bar-chart-icon will sort the grid based on the one you clicked on.

You can also exclude data if you wish. After clicking on a data item, the charts will filter, and after they finish reloading the same data item’s mouseover popup (a tooltip that appears when your mouse cursor is on it) will have further options appear (Keep Only and Exclude). They allow you to further restrict which data is shown to you.

The controls that appear on the map when the mouse is over the map allow you to search for a place on the map, zoom in, zoom out, return to the original view (the house icon), or change how the mouse functions on the map.

If all else fails and you have no idea how you got somewhere and wish to just reset it, simple reload the webpage and it will revert to the default.

What's the difference between Crashes, Vehicles, and Persons?

When a crash occurs, it is a single crash no matter how big or how many individuals were involved. But, there could be more than one vehicle involved in the crash. Sometimes many vehicles! Also, there could be many people involved in the crash, such as drivers, passengers, pedestrians, etc.

So, when you switch between Crashes, Vehicles, and Persons, you are changing which unit of information you are interested in. If you want how many fatal crashes happened, choose Crashes. If you want to know how many fatalities happen (how many people died), choose Persons. If you’d like to know how many vehicles were involved in these crashes, choose Vehicles.

There are two dropdown boxes that say "Year". What do they do?

All the filters (checkboxes, dropdown boxes, etc) on the right side of the visualization change all the data in the visualization. So, the “Year” dropdown box under the “Time” heading on the right side allows you choose which year(s) you wish to see data for. The “Year” dropdown box embedded in the “Trend” title box allows you to change the bar chart to further break down how the chart is displayed.

What's a "Troop"?

Coverlab Analytics (this visualization has been taken from Coverlab Analytics) was built mainly for the MCE (Motor Carrier Enforcement) section of the NCSHP (North Carolina State Highway Patrol). The NCSHP is broken down into geographical sections around the state called Troops.

What does it mean by "Reporting Agency"?

The Reporting Agency for the crash is the department that responded and reported the crash. For example, if the Raleigh Police Department reported a crash, then they are the Reporting Agency for that crash.

What are the Severities?

There are 5 different kinds of injuries that the various reporting agencies use when describing the severity of a crash.

  • “A” Type Injury: A very serious injury that has caused apparent disabling injuries.
  • “B” Type Injury: An injury that is evident, but not severe enough to cause a disability.
  • “C” Type Injury: A possible injury occurred, but without medical diagnosis, cannot be determined.
  • “O” Type: No injury occurred as a result of the crash event.
  • “K” Type: At least one person was killed as a result of the crash.

There are extensive definitions for each type, so if you need further details, please contact your local enforcement agency.

I want to know more details about a specific crash. Where can I get those details?

Coverlab Analytics (this visualization was taken from Coverlab Analytics) is a planning tool for determining the best course of action in reducing crashes and fatalities. Sometimes the details of a crash are necessary in this planning. The NC Highway Patrol has access to these records, but the general public does not have access to the sensitive information included in such incidents (such as names, etc).

This visualization’s goal is not to help the user find a crash to investigate, but rather to help show trends and statistics about CMV crashes in NC. If you wish to know more details about the crash, please contact the associated Reporting Agency to that crash.

What are the Road Classifications?

The road in which the crash occurred is put into the following categories:

  • I = Interstate
  • US = US Highway
  • NC = NC Highway
  • SR = Secondary Road
  • LCL = Local Road

Could you explain the large grid chart at the bottom?

The Contributing Circumstances grid chart at the bottom of the visualization allows you to see all the contributing circumstances that contributed to the crash broken up into the vehicle type(s) of that crash.

A Contributing Circumstance is some event, ability (or lack of), action, or environmental occurrence that directly contributed to causing the crash. Note that this data does NOT say that the cause of the crash equals the contributing circumstance. We are also only showing the circumstance that MOST contributed to the crash, though it’s always possible that many other factors contributed to a crash. This judgement is made by the officer/trooper that responded and reported the crash.

If you click a contributing circumstance name (rows) or click a vehicle type name (columns), it will filter and show only that circumstance/vehicle type. If you want to sort the grid, hover your mouse cursor over the name and find the small bar-chart-icon that appears. Clicking on that bar-chart-icon will sort the grid.