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Currently, map databases combine the location of roadways with their posted speed limits to estimate the time it will take a driver to get from point A to point B. So, if a driver looks up directions from her house to the airport using an in-car navigation device or portable navigation system, the system would use the posted speed limits. Depending on the time of day and where the driver lives, that information could be grossly inaccurate, explains Mistele. The new software gauges how fast each segment of road is flowing based on the time of day and the day of the week, providing a more precise estimation.
The only comparable product on the market today is developed by LandSonar, a San Francisco-based company. Its software is also based on historical traffic data that is integrated with digital maps. The company recently partnered with TrafficCast to launch an updated version with more data and real-time content, but its product remains limited to only 450,000 miles of roadway for three days of the week.
Tele Atlas's product also offers real-time updates. But this real-time coverage is limited to about 94 cities right now. It will be most efficient when used with the historical traffic-speed information, says Mistele.
A new version of the Tele Atlas software will be released every quarter, or every time the company offers a new map database. The software will be constantly upgraded, incorporating the changing traffic patterns and giving drivers a more robust, efficient navigation experience.
Agree with the previous reaction. If enough people use the system and follow its advice, escape alternatives themselves clock-up.
The use of historical data to predict where it is going to be busy on the road is only useful for people driving roads not familiar to them. People who drive the same roads everyday know when it gets busy where and will not need the information.
Also, the historical information does not allow for spotting real-time traffic incidents and it is often these incidents that cause the traffic jams in the first place. It seems that the systems under disussion are not set up to spot such incidents.
TomTom, a manufacturer of navigation devices, is testing a system in the Netherlands in co-operation with Vodafone: they claim their system can identify traffic conditions in real time by using tracking the flow of mobile phones. By superimposing this data on the road network, they claim their system can make good guesses on where traffic flows and where traffic does not. They use the location and movement of mobile phones as a proxy to assess road conditions and use this information to give customers route planning advice. How useful this is remains the question, because, as for the systems discussed in the article, escape-route alternatives are scarce and clock-up quicky if too many people make use of re-routed suggestions.
this information is still very useful for routing algorithms, etc. currently most routing algorithms use speed limits for determining the cost of a certain stretch of road.
obviously using data like this in routing algorithms will be more accurate than blindly using speed limit data on a freeway that's congested every afternoon.
Real time flow maps on the dashboard
Try realtime mapping of traffic flows to dasboard of all cars participating. Bottlenecks would show up fast enough and could be compensated by the driver. A real-time version of MS Project would do the trick, too, I think, because other constraints are easily added to determine critical pathways. I think I will try this approach. All I need is your data overlayed with realtime dwonloads and the critical path realtime traffic hypermap is born. this is problem that bother me over the years. Good going.
Charlie
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fiberman
186 Comments
Does it work?
Everybody I know in Germany uses Nav systems all the time. When I tried it, I immediately found a fatal flaw. The Nav system tells you where there are backups and how to go an alternate route. Trouble is, it's telling everybody the same thing. I had the system tell me there was a 3 min backup 1 km ahead but I should take the next exit to avoid it. I did as told and was immediately informed I was not 5 km from another backup which would take 15 minutes to clear caused by rerouting traffic from the first backup.
Garbage in - garbage out!
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jwoodside
6 Comments
Re: Does it work?
They clearly need to monitor in real time also how many people are monitoring their advice and how they are responding to it in order to provide fast correction to that advice. Sounds like it could be confusing... "take the next exit... no don't because everybody is doing that... no they've changed their minds again..."
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Guest (Troubadour )
Re: Does it work?
Feedback loops like that are a tricky problem in real-time flow guidance systems, similar to the "porpoising" experienced in early incarnations of fly-by-wire aircraft. The only way to avoid it would be for the system to anticipate the consequences of its own recommendations on users and adjust for them in advance, creating equilibrium flow.
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