Mapping Traffic Flow

Comments

• Does it work? fiberman on 05/24/2007 at 1:30 AM

  Posts: 39 Avg Rating:

  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! Rate this comment: (Reply)

  • 	Re: Does it work? jwoodside on 05/24/2007 at 3:31 AM
    Posts: 5 Avg Rating:	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..." Rate this comment: (Reply)

    • 	Re: Does it work? Troubadour on 05/30/2007 at 3:46 AM
      Posts: 2	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. Rate this comment: (Reply)

• not much room to manouver dirkatbold on 05/24/2007 at 3:44 AM

  Posts: 1

  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. Rate this comment: (Reply)

• 	still useful jezemine on 05/25/2007 at 2:26 PM
  Posts: 1	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. Rate this comment: (Reply)

• Real time flow maps on the dashboard Silacon on 05/30/2007 at 10:26 AM

  Posts: 33 Avg Rating:

  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 Rate this comment: (Reply)