How Yandex.Traffic Works
Yandex.Traffic shows the picture of the current traffic conditions in a city. It gathers information from different sources, analyses this data, and maps the results on the city’s map on Yandex.Maps. For the larger cities, where traffic jams is a serious problem rather than a small inconvenience, the service also calculates the average levels of traffic congestion on a scale from 0 to 10. To put on the map the accurate and current picture of traffic conditions in the city, Yandex.Traffic goes a long way.
Sourcing data
Imagine getting in a small traffic accident – no victims, just a couple of scratches. Your bad luck blocked two out of three lanes on a major city road. The drivers in these two lanes now have to drive around your scratched vehicle, while the drivers in the third lane have to let these cars into the unobstructed lane. Some of the drivers in this lane use the Yandex.Maps application on their mobile devices, which sends information about movements of their car to Yandex.Traffic. As these drivers are approaching the spot of your accident, they are slowing down, and their mobile devices start signaling a possibility of a traffic jam to the service.
To participate in the common effort of gathering traffic information, a motorist needs an internet-connected mobile device (cellphone, smartphone, PDA) with a GPS function (built in or using an external receiver). After downloading the Yandex.Maps mobile application and activating the “Send traffic information” option, the user can be sure that their device will be sending its geographic coordinates, direction and speed to Yandex.Traffic’s automated analytical system every several seconds. All information is non-personal, which means that there is nothing that could possibly betray any specific information about the user or their car. Then, using all available data, the automated analyzer creates a track, an integrated route for each vehicle considering the speed, with which this vehicle drives along this route. Along with contributions from private users, traffic information is also supplied by Yandex partners, the companies, whose fleet vehicles operate in the city on a regular basis.
In addition to sending their coordinates to Yandex.Traffic, drivers can also signal to the service about traffic accidents, road works or other potential causes leading to congestion. Having spotted your accident, for instance, a conscious driver can mark it on the map in his mobile Yandex.Maps application.
Tracks Processing Technology
To make a track for a moving car, Yandex.Traffic needs a number of geographic coordinates of this car provided by the driver’s GPS device and sent to the service by the Yandex.Maps application. The problem here is that GPS accuracy allows for errors between one and ten meters in any direction, which may result in “moving” your car on a sidewalk or to the rooftop of the nearest building. GPS coordinates provided by the user are mapped to the city’s electronic map, which accurately displays buildings, parks, roads with all markings and other urban facilities. This detailed mapping allows the system correct the course of a car based on the real physical layout, even if the GPS coordinates say that the car is on the wrong side of the road or has cut through a building instead of turning around the corner following the road markings.
Another important issue is to understand how useful the speed information received from the driver is, as it may or may not truthfully reflect the real situation on the road. The reason why the driver sending information about his movements via Yandex.Maps application has slowed down or stopped may not be the general traffic conditions, but that he was not sure if he needed to turn, or wanted to grab some milk from a corner shop. If all other cars on the same route that send information to Yandex.Traffic proceed as normal, the rogue track will be ignored by the system for evaluation of the general traffic intensity. That is why the number of users matters. The more drivers use Yandex.Maps to send information to Yandex.Traffic, the more accurate the picture of the real road situation is.
Using several reliable tracks, the system colors a particular segment of the road on the map “green”, “yellow” or “red” depending on the traffic density on this section of the road.
Merging Data
The next step is to bring all available information together. Every two minutes a program aggregates like a jigsaw puzzle all information from the users of mobile Yandex.Maps and maps the results on the Traffic Jams layer both in the mobile application and on Yandex.Maps online.
Point scale
For Moscow, Saint Petersburg, Ekaterinburg and Kiev, where traffic jams almost have turned into a natural disaster, Yandex.Traffic offers a ten point scale for levels of traffic congestion, with zero points meaning free flowing traffic and 10 points signaling a ‘complete standstill’. This scale helps drivers to instantly estimate how much time roughly they are likely to waste in a traffic jam. So, an average seven points for Kiev will mean for a driver that the travel will take approximately twice as long as when the traffic is free flowing.
For each of the cities, the scale is localized – what is a slight sluggishness in Moscow is a big problem in some other city. Congestion level of six points in Saint Petersburg will make a local driver waste as much time as a motorist in Moscow would spend traveling at five points.
The congestion level scale is based on reference time, which is the time it takes for a car to drive through a standard route, which covers all main roads and avenues, without breaking the law. Considering the general traffic congestion at the moment, the aggregator program calculates the difference between the reference time and the time calculated from the speed information it receives from each particular driver. Using the time difference for every single route, the program calculates the mean average, which translates into points of traffic congestion level for the whole city.
