Many modern in-car navigation devices, such as sat navs and mobile devices, have the ability to show live traffic situation or even estimate what the traffic will be like at a future day and time. If you are interested to know how live traffic and traffic prediction services work and how accurate they are, read on.
For decades, various private and public-owned organisations were installing road-side sensors to measure traffic density. The sensors vary from relatively simple pressure-activated cables stretched across the road surface to more sophisticated electromagnetic devices, operated by radar, laser or infrared.
Although there are many different types of sensors, they have one thing in common: they are expensive to install and operate. Therefore, until relatively recently, the data that the operators of the sensors have collected had to be sold at high prices. However, this has changed somewhat when manufacturers of sat navs and owners of web-based mapping services, such as Google Map, began wholesale buying of the data. So, those roadside sensors are the primary source of live traffic information.
To increase the accuracy of live traffic feed, the suppliers of GPS services began croudsourcing the data. For example, when Google Map is running on your mobile device and your geolocation service is on, your device will send your position to Google through a mobile network. While your speed and the speed of the nearby devices is calculated, averaged and compared against the speed limit on that particular road, the live traffic web services are able to determine what the level of congestion on that road is. This has not only improved the accuracy of live traffic updates, but also enabled the service in the places where it wasn't previously available. Although a reasonable mobile coverage would still be required for the service to work.
Sat nav manufacturers, such as TomTom, incorporated the same principles into their live traffic services. This is why the devices with this service available always use SIM cards.
More devices mean more accuracy, so GPS service providers went one step further by starting to buy geolocation data directly from mobile network operators. For example, TomTom buys its data from Vodafone. Therefore any mobile device with GPS enabled can be contributing as one of the sources of live traffic data.
Automated data is not the only source of live traffic information. Users can also report any extraordinary occurrences, such as accidents. Google, for example, uses Waze app for this purpose. Reports from this service is what can be seen on the traffic layer of Google Map as small icons representing road works, accidents and other events. Sat nav manufacturers use similar reporting services.
Because the processing of geolocation data has some significant costs associated with it, live traffic updates on sat nav are usually available on subscription-only basis. However, Google provides the service free of charge, as it can afford to fund it from a large variety of other sources, especially context-specific mass-advertisement.
All live traffic data that is collected is stored. As this data is analysed, patterns begin to emerge. So, this is how future traffic can be predicted.
Of course, traffic predictions can never be as accurate as the live traffic feed, as unforeseen circumstances can substantially alter any regular pattern. Therefore, considering that unforeseeing events are much more likely to make congestions worse rather than improve them, predicted traffic densities are not based on average metrics, but are rather skewed towards the worst-case scenario. Therefore, while planning your future journeys, you can rest assured that the journey is likely to be better than the device shows, unless an unforeseeing event happens.
Privacy and security of live traffic data
If GPS service providers are collecting so much geolocation information from users' devices, something that an average Joe would probably not even be aware about, shouldn't we be concerned? The answer to this question is both yes and no.
Due to various privacy regulations in place, companies are obliged to anonymise the data, so there would be no way to identify a particular device or its owner. The data that can identify its source by proxy is deleted. For example, Google services delete starting and end point of each journey.
Having said that, there is no guarantee that the companies actually do what they say, although they probably do. Recently, there have been many successful attacks against supposedly secured databases, so there is a remote possibility that the same can be done against a sat nav data network. Although the risk of this is quite low and the risk of anything bad happening in the case of successful breach is even lower.
There are some other security issues associated with using GPS on mobile devices, some of which were outlined in this article; however exposure to the risk depends entirely how a device is used. Those people who are highly sceptical about having their device used as the source of live traffic feed can simply turn the geolocation services off. However, if you chose not to, you would be enormously helping fellow commuters. The call is yours.
Written by Mobile Tech Tracker team
Posted on 26 Sep 2015