Traffic

# Traffic Analytics Speed Data

By Sophia Parafina | 02 February 2022

### Try HERE Maps

Create a free API key to build location-aware apps and services.

HERE Speed Data provides traffic speed observations using the same GPS probe data as HERE Real-Time Traffic. It delivers historical traffic speeds for analytical applications. It enables road network performance analysis by providing a reference “free flow” speed of uncongested traffic which can show when speed falls significantly below uncongested speed.

### Getting the data

Alternatively, you can request data using the API, which lets you request data by specifying a geographic area, such as bounding box, a user defined polygon, or boundary. The API also provides a service for polling the status of you query and will return a JSON document with a download link when the query completes.


{

"queryFilter": {

"location": {

"geometry": "POLYGON((-118.36409 33.648269, -118.14827 33.648269, -118.14827 33.658387, -118.094146 33.658387, -118.094146 33.838692, -118.309991 33.838692, -118.309991 33.828574, -118.36409 33.828574, -118.36409 33.648269))"

},

"isoCountryCode": "USA",

"locationFilter": {

"funcClass": {

"1": true,

"2": true,

"3": true,

"4": true,

"5": false

}

},

"startDate": "2021-10-01",

"endDate": "2021-10-31",

"requestType": "PROBE",

"vehicleType": "TRUCK",

"daysOfWeek": {

"U": true,

"M": true,

"T": true,

"W": true,

"R": true,

"F": true,

"S": false

}

},

"outputFormat": {

"tmcBased": false,

"epochType": 60,

"minMax": true,

"mean": true,

"stdDev": true,

"confidence": true,

"freeFlow": true,

"length_": true,

"speedLimit": true,

"sampleCount": true,

"gapFilling": false,

"percentiles": [85]

},

"estimatedSize": 0,

"userEmail": "here_user@example.com",

"userId": 1234

}


### Traffic Analytics Data

Speed data is a historical data set covering 5 years. Additionally, it is available with only two days of latency from the date of collection.

Speed Data uses GPS probe data from 100-plus providers collected globally from connected vehicles, navigation systems, fleet telematics systems, or mobile devices. Probe speed data is averaged in 5-minute increments (or optionally 15-and 60-minute increments), and presented with other measures such as minimum, maximum, standard deviation, percentiles, and a confidence measure. A reference “free flow” speed of uncongested traffic flow is included. Road network performance analysis shows when speed falls significantly below uncongested speed.

Data is referenced to the Travel Message Channel (TMC) road network or HERE Map using road link IDs. Each record contains a road segment reference (either TMC or HERE Map Link PVID), a date, the time of day in local time, and then the speed and other analytical data selected. TMCs are generally longer (multiple links) and available only for important roads. In contrast, LINK-IDs can be used with HERE’s street data, which have a higher degree of detail than TMCs.

### Calculating traffic congestion

A primary use of historical speed data is to estimate traffic congestion. A simple, effective congestion metric is (note: floor values that are zero or less):

As a simple guide, we can determine if a road segment is congested if it is 30% greater than the average free flow speed. You can aggregate across the road network by calculating a simple arithmetic mean weighted by the length of the road segment:

Speed data is unmodelled, to separate signal from noise, consider omitting records with a COUNT less than 10. Also, take into consideration the time when records were collected. Day time records will have more samples for increased traffic and can indicate more congestion. Day of the week and holidays can also affect the congestion score, for example, weekends and holidays may have less traffic. These are some factors to consider when calculating congestion.

### Visualizing congestion scores

The speed data is collected with a direction of travel, i.e., to and from along a road segment. To join the speed data records to HERE streets map data requires creating road segments with a field that combines the LINK_ID and the direction of travel, e.g. LINK_ID + DIR_TRAVEL. We can use this field to join the congestion scores calculated from the Speed Data and produce a map.

### Summary

Traffic Analytics Speed Data provides daily historical traffic speed observations on the roads across the HERE map so that traffic and road infrastructure planners can make more informed and efficient decisions. It delivers 2 types of data:

• Speed Data - Daily traffic speeds with 5-minute granularity. Available when and where probe data is collected with a 5-year historical view. Includes observation counts.
• Traffic Patterns - Delivers usual traffic speeds by day of week and time of day, by analyzing trillions of vehicle speed observations on every road in the HERE Map.  The Traffic Patterns product is a premium option on top of the HERE Map so that drivers can make more informed and efficient decisions.

Speed Data addressed the need for historical congestion data to fuel and analyze projects when it's too expensive to put data collectors into the field. Historical data enables traffic authorities to conduct before and afteranalysis, looking at historical speeds before a construction project takes place and analyzing improvements, if any, on the roads after completion of the project. Speed data can confirm traffic behavior at a specific date and time to provide a clear picture of travel behaviors throughout a region. This data can assist with spotting trends on the roadways, an increase or decrease in congestion during rush hour time periods, sporting events in a metropolitan area, etc. If you need to analyze and understand traffic patterns, consider using HERE’s Traffic Analytics Speed Data for your next project.