New Enhancements in HERE Traffic Analytics - Speed Data

We are excited to share the new feature enhancements designed to improve the accuracy and quality of HERE Traffic Analytics. HERE Traffic Analytics - Speed Data is a powerful tool for understanding historical traffic patterns and helping with the optimization of future traffic flow. It provides extensive data on road speeds, derived from a huge database of GPS readings, which means you can learn how roads perform at different times of the day and week, in different places. Speed Data contains historical data, typically six years of data, which can be used by governments, transportation agencies, and businesses to make informed decisions about infrastructure management, traffic flow management, and route optimization. These enhancements are available in the Traffic Analytics website and the Traffic Analytics API. 
 

Key Improvements in HERE Traffic Analytics - Speed Data

1. Harmonic Means

Harmonic means are one of the three Pythagorean means used to calculate the average of a set of numbers. In the context of traffic analytics, harmonic means are used to calculate the average speed of traffic on a road segment. Harmonic means are more accurate than arithmetic means, particularly during periods of congestion forming and congestion clearing, when the most variation of speed occurs. This is because harmonic means give more weight to low-speed vehicles that are important when calculating the average speed of traffic in congestion.
Harmonic means are first calculated at link levels and at 5-minute intervals for path speeds, then aggregated to Traffic Message Channel (TMC) segments and other time intervals.

Consider the example above that comprises of a set of 17 probes. The arithmetic mean in this case is 40 mph, whereas the harmonic mean is 30 mph. This speed difference of 10 mph shows the role played by low-speed vehicles in calculating the average speed. 

2. Probe Pathing

Probe pathing is a feature available in Traffic Analytics today. The path that a probe vehicle traveled between 2 sequential observation points is identified and map-matched to HERE map links, then the travel time and speed are computed based on these probe paths. The current method of probe pathing is to count the number of probes that are on each segment. However, this method does not consider the length of the probe paths. The new probe pathing method weighs the probes based on the probe counts as well as the length of their paths, which provides a more accurate picture of the actual probes on the road segments. 

3. Vehicle Distance Traveled (VDT)

Vehicle Miles/Distance Traveled (VDT) is a new metric included in the HERE Traffic Analytics offering. VDT refers to the total distance traveled by vehicles on a road segment over a given period. It provides valuable insights into traffic patterns, congestion levels, road utilization and overall transportation efficiency within specific areas. VDT serves as an important tool to view how many vehicles use the road network, helping in traffic management, congestion analysis, traffic forecast, city/infrastructure planning, environmental impact assessment, public safety, and public transit optimization.

The above figure shows the urban density through the same area for highways A, B, C and D. The daily VDT shows different travel demand patterns.

4. Probe Counts

The Probe Count value is a new parameter that replaces the previous “Sample Count” in the output. It measures the number of vehicles that are on a road segment at a given time. The traditional sample counts are based on the number of speed samples used in averaging speed calculations for a segment. The new probe counts are determined using new VDT value and improved probe pathing (segment length).

                Probe Count = Total Vehicle Distance Traveled (VDT) / Segment Length

This provides a more accurate picture of the actual number of vehicles on a road segment.

5. Increased country coverage

HERE Traffic Analytics will include coverage for the Philippines. The data is currently available for 58 countries.

6. Expanded Probe Sources

The new release of HERE Traffic Analytics includes data from several new probe providers. With more than 160 providers, the data is collected globally from connected vehicles, navigation systems and fleet telematics. Adding higher dependability on speed data from trusted Original Equipment Manufacturers (OEMs) enhances the Speed Data and improves the historical data we provide for the past five years. 

Traffic Analytics Website

The historical speed data can be requested from the Traffic Analytics website as well as through the Traffic Analytics API. You can submit the web form for the administrative boundaries such as a city, region or country; and select the output fields as needed. The Traffic Analytics Speed Data blog post outlines the specifics.  

Traffic Analytics API Request

If you are looking to request data for a specific geographical area such as a bounding box or polygon, you can request the data through Traffic Analytics API using bearer token generated through HERE platform.

        POST https://trafficanalytics.api.here.com/dailyAnalytics/requests  
  

        {
    "estimatedSize": 5117627,
    "queryFilter":
    {
        "adminId": 23869478,
        "adminLevel": 1,
        "startDate": "2023-12-01",
        "daysOfWeek":
        {
            "U": true,
            "M": true,
            "T": true,
            "W": true,
            "R": true,
            "F": true,
            "S": true
        },
        "endDate": "2023-12-01",
        "isoCountryCode": "PHL",
        "locationFilter":
        {
            "funcClass":
            {
                "1": true,
                "2": true,
                "3": true,
                "4": true,
                "5": true
            },
            "tmcs":
            []
        },
        "mapVersion": "2023Q4",
        "requestType": "PATH",
        "vehicleType": "ALL",
        "timeIntervals":
        [
            "0000-2359"
        ],
        "smoothedSpeed": false
    },
    "outputFormat":
    {
        "mean": true,
        "harmonicMean": true,
        "probeCount": true,
        "confidence": true,
        "epochType": 5,
        "freeFlow": true,
        "gapFilling": false,
        "length_": true,
        "minMax": true,
        "percentiles":
        [
            50,
            55
        ],
        "sampleCount": true,
        "stdDev": true,
        "tmcBased": true,
        "speedLimit": true,
        "vdt": true
    },
    "userEmail": "...",
    "userId": xxxx  
}
  

Traffic Analytics API Response

Whether you submit the request through the Traffic Analytics website or the Traffic Analytics API, you will receive an email with the data download link. The processed data is in CSV format with the requested output fields as below: 

Conclusion

To sum up, the latest advancements to the HERE Traffic Analytics offer significant improvements in accuracy, coverage, and traffic data insights. Harmonic means, probe pathing, VDT, probe counts, more international coverage, and more probe sources will now give access to better historic traffic patterns that can be used for informed decisions in infrastructure planning, traffic flow optimization and more. If you're interested in using these features, you can request access to the HERE Traffic Analytics - Speed Data.