On February 8, 2008, about 100 UC Berkeley students will participate in the Mobile Century experiment, using GPS mobile phones as traffic sensors. During the whole day, these students carrying the GPS-equipped Nokia N95 will drive along a 10-mile stretch of I-880 between Hayward and Fremont, California. ‘The phones will store the vehicles’ speed and position information every 3 seconds. These measurements will be sent wirelessly to a server for real-time processing.’ As more and more cellphones are GPS-equipped, the traffic engineering community, which currently monitors traffic using mostly fixed sensors such as cameras and loop detectors, is tempted to use our phones to get real-time information about traffic. But read more…
On February 8, 2008, about 100 UC Berkeley students will participate in the Mobile Century experiment, using GPS mobile phones as traffic sensors. During the whole day, these students carrying the GPS-equipped Nokia N95 will drive along a 10-mile stretch of I-880 between Hayward and Fremont, California. ‘The phones will store the vehicles’ speed and [...]
Comments
@ 16:55
Interesting experiment on traffic monitoring..
I work for a taxi company in the UK and we’ve done this within our own systems for years over here. It works as follows:
all vehicles are fitted with cellphones and GPS antennas. These are Windoze CE PDAs / phones, and they register themselves to the office servers when the drivers logon for their shifts, (and de-register upon logoff)
Whilst logged on, the cellphones fire a short message at the servers every 5 seconds, containing positional data from the GPS software, plus speed information The GPS software used is a fleet version of TomTom which has the additional attribute of taking the positional snapshots every 5 seconds. This is the source of the positional and speed data, which is processed on the cellphone by:
the taxi management application - which is the entity that communicates with the office servers via the Internet. Specifically, the protocols used are GPRS [nothing to do with GPS rather confusingly!]
One of the applications in the office translates the [Lat/Long] GPS position and displays a symbol for each vehicle showing its position, direction and speed on a map of the country.
One nice thing is that the size of the map depends on the furthermost vehicles, so if every car is working in a small area, the map displays just that, ie at large scale.
On the other hand, if a vehicle is several hundred miles away, then the map auto-zooms to include it.
The Controller in the office can click on any vehicle symbol to zoom in to see precisely where it is - down to road-name and even approximate house number. This shows even the individual buildings at complex site layouts like airports or railway stations.
As to traffic flows, in our systems it’s down to the experience of the Controller to interpret the data: at rush hour times, he expects his vehicles to be Crawling /stuck in traffic congestion on the highways, whereas at night, if he sees a vehicle driving slowly on the highway he can infer that there is a problem and schedule future jobs knowing that they will likely take longer than usual. In our systems this is human experience rather than via automation but an automatic alert could be added easily enough I guess.
In addition my own cellphone/PDA has a built-in GPS receiver, plus the latest version of TomTom which alerts me to speed cameras and even traffic congestion..
The systems work pretty well overall and make a big difference to job scheduling. (In fact, job scheduling can be completely automatic, - but most controllers prefer to do this themselves because they make use of additional information like which drivers are good at different tasks, including such things as diplomatic skills needed to deal with Masters of the Universe types..)
Howard has been in the oinkmobile on a run from central London to Gatwick airport, and can vouch that the systems still work even at high speed, - when we are rapidly crossing from one cell of the cellphone network to another yet still maintaining the Internet connection..