Road segment traffic analysis

Road Segment is one of the aggregation modes in the Traffic Analytics application.

Setting up a Traffic analysis with Road Segments

Learn how to set up a Traffic analysis using the Road Segment type of aggregation, including data loading and filter settings.

To set up a Traffic analysis using the Road Segment type of aggregation:

  1. Select Road Segment from the two types of aggregation.
  2. Load data for the region(s) you want to analyze.
    1. Click the arrow next to the Select dataset dropdown to select the country where your analysis will take place. You can also search for a country by typing in the search bar.
    2. Once you select a country, a list of its subregions (states or provinces) displays. If you want to select an entire subregion, select the Counties in or Subdivisions in the box beside the subregion's name in the County or Census Subdivision section. Click Continue.
    3. To drill further into a specific location, click a subregion's name to view its subregions (cities, towns, etc.) Click any subregion's name to include it in your analysis. Click Continue.
  3. Set Traffic Filters, then click Load data.

Running a Traffic analysis with Road Segments

Learn how to run a Traffic analysis using the Road Segment type of aggregation, including segment analysis and selection.

After setting up a Traffic analysis using the Road Segment type of aggregation, including adjusting filters and loading data, you can continue to run an analysis.
  1. Once the Road Segment data for the dataset you have selected is loaded, you can see a high level view of all the Road Segments clustered within the boundaries of the selected area.
    1. Open the Road types dropdown to select the road type you wish to include in your analysis and click Apply. You can select multiple road types.
  2. Zoom in to see the Road Segments in more detail.
  3. The legend at the bottom of the window indicates the speed traveled on each road segment. Click the dropdown menu to choose which metric you would like to display. Move the slider on the legend to filter the results.
  4. Hovering over a section of road brings up a tooltip with basic speed information. Click the segment to go to the Select road segments to analyze page.
  5. Using the Map, select Road Segments for your analysis using Single segment or Connected segment selection. Single segment selection allows for the selection of smaller, individual road segments for analysis. Connected segment selection allows for the selection of multiple adjacent road segments at one time (grouped by OSM Ways).
    1. If you are using Single segment selection, select the road segments you wish to include in your analysis by clicking the segments. It is not mandatory for segments to be connected, however missing road segments will disable Directional Analysis. Remember to always zoom in to ensure you do not miss any Road Segments, as they can be very small. When reviewing the results for a single segment, the Observed Count displays.
    2. If you are using Connected segment selection, you can select any part of a road segment included in an OSM Way and all other related segments will automatically be selected as well. Clicking any segment in this path will automatically select the rest when using Connected segments. Direction will be signified on the map at the end of each connected segment and can be changed using the Travel Direction option.
  6. You can view or remove any segments included in your analysis in the top right window. To remove a segment from your analysis, click the X next to that segment. To clear all the segments from your analysis, click Clear selections and the Clear Selections and Filters popup displays.
  7. Click Travel direction to reorder segments.
    1. Selecting from the Travel direction dropdown menu allows you to understand the speed and travel times along the direction of travel. If a single segment is selected, a cardinal direction of travel will be shown. If multiple are selected, direction of travel will be defined by which end of a connected segment the travel should start from; by default, travel direction is set to be the average across all directions of travel.
      Note:

      If multiple, disconnected road segments are selected, travel directions cannot be defined as each road segment can have different travel directions.

  8. Click Run analysis.

Reviewing Road Segments analysis results

Learn how to review the Traffic Details panel for your Traffic analysis with Road Segments, including a Summary and Trend analysis based on selected metrics.

After you set up a Traffic analysis to load data and run an analysis for the selected Road Segments, you will see the Traffic Details panel with results.
Review the Traffic Details panel, which provides a Summary tab with of Characteristics and Measurements of your selected Road Segments, and a Trend analysis tab which offers insights based on up to three metrics.
  1. The Trend analysis tab allows you to Choose metrics to display from the menu for trend analysis. Select up to three metrics, with a maximum of two units. There are four tabs on the menu: Travel Speed, Spot Speed, Travel Time and Characteristic.
  2. Click Apply to generate three charts with the metrics that you have selected. Hover over a data point to view additional information.

Metrics for Road Segments

Below the Road Segments and Traffic Filters sections, you can see a Summary tab that contains metrics for the selected road segments in various categories, including measurements like Travel Speed, Spot Speed, and Travel Time (avg).

The Trend analysis tab allows you to Choose metrics to display from the menu for trend analysis. Select up to three metrics, with a maximum of two units. There are four tabs on the menu, Travel Speed, Spot Speed, Travel Time and Characteristic.

Note:

You may only choose three metrics total from the entire menu, and only display up to two different units.

Travel Speed

The Travel Speed is the average speed calculated using the data for the total length of those roads divided by the time taken to travel across those Road Segments. It provides useful information for the selected Road Segments, such as:

Average Travel Speed
Displays the result for the average Travel Speed.
% of Trips Over the Speed Limit
The percentage of the vehicle passes where the Travel Speed was over the speed limit.
% Free-flow Travel Speed
The average speed a vehicle will travel under ideal conditions, such as no congestion.
Note:

This metric is considered a characteristic of the road and not impacted by the filters used.

Pace
The speed range (measured in mph or km/h) with the highest share of traffic.
% of Speed Limit
The average Travel Speed as a percentage of the weighted average speed limit.

Spot Speed

The Spot Speed is the average of the maximum individual speed observed as the vehicle drives through the selected road segments. It provides useful information for the selected Road Segments, such as:

Average Spot Speed
Displays the result for the average Spot Speed.
% of Free-flow Spot Speed
Spot speed as a percentage of the Free-flow speed.
% of Speed Limit
The average spot speed as a percentage of the weighted average speed limit.

Travel Time (avg)

If you perform a directional analysis, there will be a Travel Time (avg) metric. This metric describes the average time taken for a vehicle to travel across all selected roads or through a selected path. It provides useful information for the selected Road Segments, such as:

Travel Time (avg)
The average time taken for a vehicle to travel across all selected roads or through a selected path.
Travel Time Reliability Ratio
The ratio of free-flow to median travel time. Values closer to 1 indicate that the travel time of the slowest 15% of vehicles and the median are almost the same. A high value indicates that the slowest 15% of vehicles are much slower than the median. (i.e. reliability ratio of 2 implies that the slowest vehicles are 2x slower than the median).