Explorer
The Explorer provides a quick insight into the situation at the location. To display the data quickly, some choices have been made in the calculation method that compromise the accuracy of the data. A significant difference between the export and the Explorer is that the calculated data comes from a different database. For the export functionality, all data is stored in the smallest available aggregation (usually minute level), while in the Explorer, for processing time reasons, the data is fetched from a database where hourly aggregates are stored. This means that the results from the Explorer and the export can differ. For detailed analyses, data should be requested through the export or reporting function.
Intensities and Speeds
Explanation
In the Explorer, hourly average intensities and/or speeds are shown for measurement locations that measure one or both indicators. A period and location must first be selected. The locations that are active in the selected period will appear in the location selection screen. After location selection, the measurement completeness can be checked by clicking "Show Measurement Completeness" to see which share of the minutes the locations have provided data for in the selected period. After clicking the "Explore" button, the data will be displayed in both graph and table form. When hovering over the graph, a label will show the measurement value and timestamps. It is possible to zoom in on a specific time period by selecting a period in the graph. When zoomed in, the "Restore Zoom Level" button will appear in the top left of the graph, allowing the user to return to the original period. Using shift, the graph can be shifted within a time period. When one of the lines is clicked in the graph, a more detailed overview of that location will appear, and the following tabs will be visible:
- Intensity and Speed
- Intensity per Lane
- Speed per Lane
- Intensity per Vehicle Category
- Speed per Vehicle Category
Below the graph, the data is displayed in table form. Days must be expanded, and columns can be dragged.
Calculation Rules
The hourly aggregates of the intensities are determined as the arithmetic average of all available minutes within the hour. Since the displayed unit is always vehicles per hour, there is no need to correct for missing minutes:
Where:
\(I^{hour}\): The average intensity for the relevant hour in vehicles per hour
\(M\): The number of minutes delivered in the relevant hour.
\(I_i\): The intensity in minute i in vehicles per hour.
These hourly aggregates are calculated per lane, per vehicle category, and for the anyVehicle category. The sum of the available lanes is then the lane average.
The hourly aggregates of the speeds are determined as the weighted harmonic mean of all available minutes within the hour.
Where:
\(V^{hour}\): The average speed for the relevant hour in kilometers per hour
\(M\): The number of minutes delivered in the relevant hour.
\(v_i\): The speed in minute \(i\) in kilometers per hour.
\(a_i\): The number of observations on which the speed measurement in minute \(i\) is based.
When the number of observations is unknown, the value 1 is used for \(a_i\) and a normal harmonic mean is calculated. These hourly aggregates are calculated per lane and per vehicle category. The average across the lanes is the weighted harmonic mean of the available lanes.
Travel Time
Explanation
In the Explorer, after selecting the period and route(s), the hourly average travel time is shown. Only the routes that have been processed in the current data stream are visible in this list. If another route is desired, it can be analyzed via the Explorer --> Floating Car Data. By clicking the "Show Measurement Completeness" button, the number of minutes for which a travel time value has been provided within the selected period will be shown and can be filtered based on low measurement completeness. A value is missing for an hour only if no minute data has been provided for that hour. By default, the (converted) speed over the route is shown in the graph for the selected period. The second tab shows the travel time for the data selection. The graph can be zoomed into a specific period by holding the mouse button and moving it from the start to the end of the period. Below the graph, the data is available in table form. This can be expanded by clicking on the data, and columns can be dragged, sorted, or widened. With the "Export Selection" button, the export request screen is opened with the selected data from the Explorer.
Calculation Rules
The hourly average travel times in the Explorer are the arithmetic average of all available minutes in the selected hour:
Where:
\(R^{hour}\): The average travel time for the relevant hour in whole seconds.
\(M\): The number of minutes delivered in the relevant hour.
\(R_i\): The travel time in minute i in whole seconds.
When only one minute is available in the relevant hour, this value is taken as the hourly average. However, this will result in low measurement completeness.
Floating Car Data
Explanation
After selecting a period, a route can be selected in the Netherlands using the "Select Route" button. A route can either be created or chosen from one already created within the organization. By default, the (converted) speed over the route is shown in the graph for the selected period. The second tab shows the travel time for the data selection. The graph can be zoomed into a specific period by holding the mouse button and moving it from the start to the end of the period. Below the graph, the data is available in table form. This can be expanded by clicking on the data, and columns can be dragged, sorted, or widened. With the "Export Selection" button, the export request screen is opened with the selected data from the Explorer.
Calculation Rules
Compared to travel times under the "Travel Time" section, there are some differences. The Floating Car Data network is divided into segments of a maximum length of 50 meters. For the routes based on FCD in the current data stream, the travel times are calculated per minute over the entire route and for the Explorer, hourly average travel times of these routes are determined. This is how travel times are processed under Explorer-Travel Times. However, for the routes under Explorer-Floating Car Data, hourly averages are first determined from the segment data. The hourly average segment data is the arithmetic average of all available minutes for the segment in the relevant hour:
Where:
\(R^{hour}_{s}\): The average travel time for the relevant hour in whole seconds for segment s.
\(M\): The number of minutes delivered in the relevant hour.
\(R_s^i\): The travel time in minute i in whole seconds for segment s.
From the hourly average segment data, route travel times are determined. This involves calculating the share of each segment within the route. The travel time of the segment is weighted based on the share it has within the route.
Where:
\(R_{hour}\): The average route travel time for the relevant hour
\(S\): The number of segments within the route
\(fract_s\): The share of segment \(s\) within the route
\(R_s^{hour}\): The average hourly travel time for segment s.
Situation Messages
This application is still under development and will be further expanded and refined. Currently, bridge openings and traffic jams are displayed on the map for a one-hour time window. After selecting a time, you can look half an hour back and half an hour forward using the playback button.
Matrix Signal Information
After selecting the period and matrix signal controllers, the image states are shown. Each matrix signal controller represents a location and a lane. The lanes are numbered from the median, so the lowest number is the leftmost lane, and the highest number is the rightmost lane. When all lanes are selected, they are displayed in the correct order on the screen. Loading the image states may take a while. With the "Export Selection" button, the export request screen is opened with the selected data from the Explorer.
Data Quality AVG
Data quality represents the quality of the current traffic data (intensities, speeds, vehicle categories, and travel times).
Explanation
After selecting a time period and contract(s), the results of the various contracts for the delivery of intensity, speed, and travel time data will be displayed in the graph. The quality of measurement completeness (current and historical), maximum outages, long-term outages, and delivery times can be viewed. The results are shown per month in the graph. Measurement completeness is the percentage of minutes for which the minute has been delivered completely correct without an error value. For "on-time" measurement completeness, it is also checked if the data was delivered on time. Late deliveries are therefore considered incomplete in this calculation. Availability checks not only if a value has been delivered, but also if 97 percent of the locations for each minute in the selected period deliver correctly. In practice, this norm is replaced by measurement completeness. The maximum outage checks the percentage of measurement locations in the contract that comply with the maximum outage standard (usually no more than 25 percent of the time in a month). The long-term outage checks the percentage of measurement locations in the contract that remain within the standard for maximum consecutive outage within a month (usually no more than 120 hours). Delivery time is the percentage of deliveries received on time. A delivery is on time if NDW receives it within the agreed number of seconds after the minute in question (usually 40 seconds).
Contracts
Under contracts, the same data as in Data Quality AVG can be viewed, but the results are shown for one month instead of over a longer period. In this graph, multiple prefixes can be compared.
Calculation Rules
On-time measurement completeness is the number of (on-time) received minutes of technically correct data divided by the number of minutes in the period. For the agreed contract locations (incl. #lanes and the vehicle categories to be delivered for that location) for the applicable MST (for that minute of the day). So for any vehicle, but also for each vehicle category per lane, that minute of data must be received. If data is missing from one or more of these 'cells' (value -1), that minute is not considered complete. A distinction is made between measurement completeness of the current data stream (on-time measurement completeness) and historical data, including late deliveries. Technical exclusions (=incorrect data) have counted as incomplete since 2022 in the calculation. Contract exclusions are excluded from the calculation. Note, if during a period of contract exclusion, the data was correctly delivered, those minutes will still count in the calculation.
SHIVI
SHiVi stands for Samenwerking Historische Verkeersinformatie. NDW and Rijkswaterstaat have jointly renewed the information chain for historical traffic data on the HoofdWegenNet (HWN) in this collaboration.
SHiVi contains intensities per SHiVi traffic lane, per 5 minutes, per day, and speeds per SHiVi segment, per 5 minutes, per day. Both have been available since January 3, 2019.
A SHiVi traffic lane refers to a road section where traffic moves in one direction, and no traffic can enter or exit (except at service areas). Each traffic lane is subdivided into one or more (SHiVi) segments. A segment is a portion of a traffic lane with the same number of lanes, speed limit, and a maximum length of 300 meters.
Intensities (in vehicles per hour) are calculated from the available point measurements on a traffic lane. If multiple measurements are available, the median is determined per minute. The intensity is then calculated per 5 minutes.
Speeds (in kilometers per hour) are calculated per SHiVi segment by averaging the speeds from Floating Car Data, with consideration for the segment length.
The SHiVi result is a clearly defined value for intensities and speeds per traffic lane/segment on the HWN. Intensities cover approximately 60% of the entire HWN; speeds, due to the use of FCD, are nearly nationally covered.
SHiVi data can be viewed through the SHiVi Explorer for intensity/speed. The usage is similar to explorers for intensity, speed, and travel time. In the SHiVi explorers, you can select a date range and traffic lanes or segments.
You can also draw a route, and the traffic lanes/segments will be automatically selected. The result is a graph with the hourly average values. Below the graph, data is shown in table form when the relevant hours are expanded.
With the SHiVi time-distance diagram explorer, it is possible to create a time-distance diagram (or speed contour plot) for a selected period and days based on a drawn route.
It is also possible to zoom in on graphs and time-distance diagrams. A time-distance diagram can be saved for further reports.
Always start by selecting the date range. The location selection is removed when the date range is changed because the SHiVi network can vary per month.
Bicycle Data
Explanation
The bicycle intensities from different bicycle measurement locations can be displayed in the graph. A period and one or more locations need to be selected for this. Many bicycle measurement locations only measure periodically. The location selection table shows when a location’s periodic measurements are valid, typically starting from the first periodic measurement. However, when a location spans multiple years, it is unclear which three weeks are measured in subsequent years without additional information. It may be wise to first explore a longer period.
It is possible to compare multiple periods by adding a selection. A second graph will then be displayed. The graph shows the hourly intensities.
Calculation Rules
The hourly average bicycle intensities are calculated as the arithmetic mean of the deliveries for the respective hour.
Where:
\(I^{hour}\): The average intensity for the relevant hour in vehicles per hour. \(M\): The number of minutes delivered in the relevant hour. \(I_i\): The intensity in minute i in vehicles per hour.