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Check Traffic Congestion Online
braddk writes "Looks like traffic helicopters will slowly become unnecessary in Denver, as an ongoing construction project implements online traffic data. The traffic is monitored via "vehicle counters" placed at the onramps and in between interchanges. Although only a 10 mile section is currently monitored, plans are to add more sensors as they complete sections of the larger project. They also have a lighter version for mobile phone users.
Click here to see the Flash version
and to check out the current traffic in Denver. Now I can check whether I really want to head to work in the morning." Kinda like that project in Finland.
Atlanta's traffic Sure it is not in pretty flash, but is is much more extensive.
It's great when someone finally implements new and
:)
inventive stuff in real life IT environments. Now
if they could just do it in my country.
I love the idea of getting a sms saying that it's
going to be 3 hours in traffic before you get home
The reporters can sit in their studios and follow the congestions real-time and will report it with regular intervals on the news. Works fine.
Aren't similar systems in use in lotsof other places?
I'm in a Unix state of mind.
We've had this in the UK for a decade. It's called traffic master. Speed senors are mounted on freeway bridges all around the country and provide constsnt traffic flow information, which can be relayed to a map display on the dash.
Speed sensors give rather better information for this purpose than car-counters. See http://www.trafficmaster.co.uk/
This sounds like the Coordinated Highways Action Response Team. It has an interactive map with colored arrows indicating the speed of traffic on both sides of the highway for a variety of roads in the DC/Baltimore area.
(But please don't Slashdot it, or I won't know if it's safe to leave for work!)
Seattle's had maps like this for years, and they work quite well:
http://www.wsdot.wa.gov/PugetSoundTraffic/
They don't read speed directly, but rather chart traffic density by measuring the changes in inductance of 6 foot metal loops embedded in the highway every 1/2 mile or so. They count cars passing over the loops and measure the time a car spends over it.
From the WSDOT FAQ:
"How are "Stop and Go", "Heavy", "Moderate", and "Wide Open" defined?
Their definitions are based on a measurement called "loop occupancy". This is the percentage of time that a 6 foot square loop sensor is activated, or occupied, by vehicles traveling over it. Loop occupancy is measured by sampling the loop detector at a rate of 60 times per second. Each sample results in a "loop occupied" or "loop not occupied" response. A counter is incremented once for each "loop occupied" response. After 20 seconds, the total number of "loop occupied" responses is divided by 1200 (the total number of samples in a 20-second period) and then multiplied by 100 to get a percentage. The result is known as occupancy. On the map, "Stop and Go" (or BLACK) is defined as occupancy greater than 35%, "Heavy" (or RED) is 22-35% occupancy, "Moderate" (or YELLOW) is 15-22% occupancy, "Wide Open" (or GREEN) is below 15% occupancy. "
Nothing new in France either.
Roads have had sensors for at least a decade.
Used for different purposes
- traffic monitoring (accidents, etc.)
- driver information by huge screens on the road, telling how long to this and this direction ; and I find it really nerve calming to know how long it will take and be able to organize (once it only said how long - in distance - the congestion is, which I don't care about)
- website for 4 years.
Here we have two type of sensors
- simple loops, which only give information about the "coverage rate" (that is, proportion of time there is a vehicle on the loop. Funnily, this figure is heavily correlated with the state of traffic and the speed of the vehicles. 0.1 is heavy traffic and 0.2 is congestion. I do not recall exacly the figures but you get the highest throughput for a magic "coverage rate" which corresponds to around 57 kmph (~37 mph).
- double loops are simple loops 1 meter away ; correlating data from the two gives you the time decay between them and so the speed of vehicles, in a more reliable fashion than just simple loops ; in particular with these you can ajust the nominal traffic model with observed speeds so your model integrates real road conditions (snow, rain, saturday night...) and single loops can then give you very accurate information.
On heavily trafficked roads (eg Boulevard Peripherique in Paris) you have a single loop every 400m and a double every 2km AFAIR.
Yeah, the ***creepy*** thing about Houston's system is the way they calculate the speed of traffic flow. The toll system has a little gadget called EZ-TAG that lets you zip through the toll plazas without even slowing down. It has a little radio transmitter that talks to a reciever in the plaza. The traffic monitoring system has checkpoints that monitor these, and since it can uniquely identify you, it knows your average speed for that segment. They ***say*** that they won't ever use it against you (ie to write speeding tickets) but if they ever start, if will be back to coins for me. Or at the very least, a special RF blocking case to protect me from the eye in the sky...
the parent post was probably right, given that the link is:
http://traffic.tamu.edu/incmap/incmap.aspx
JDR
You assume the sensor is "dead," but these traffic management systems set ramp meters based on conditions further down the road. Traffic may be rushing towards a stop. Minneapolis-St. Paul has had these sensors and ramp meters for years now. One of State Senators got a bug up his backside about them and forced MnDOT to do a "study" (well, it was a real study) that involved shutting down all the ramp meters for weeks. The results? A disaster. Congestion increased severly on most roads. Most trips *increased* in drive time (yes, even when you include time spent being an "asshat" at a ramp meter).
The interesting thing was that this was not 100% true. Some routes got better. And drive times improved over the course of the study, although they didn't come back to anywhere near as good (on average) as they were before metering. In other words, people found alternate routes.
One outcome of this was the appearence of lighted arrow signs along side streets of the most congested highways that come on to point motorists on to alternate routes when congestion is severe. Unlike the ramp meters, these are mere suggestions. But it seems to have improved things.
Transit is a huge political issue here. The Republicans took over Minnesota government last election largely by promising massive road building instead of public transit. That's pretty remarkable for MN which has long been considered a Democratic stronghold. People get "het up" about traffic.
Traffic metering WORKS. Sure, you get annoyed waiting on the ramps, but they really do improve travel time.
Oh yeah, the study did improve their meter rates. They were able to speed some meters up and slow some others down and *improve* travel times over the pre-study metering system. It didn't stop me cursing that senator every time I commuted during the study! BTW, in 2001, when the study was done, there were 233 metered ramps in the metro area during the morning rush, and 283 metered ramps in the afternoon rush. I don't really know how many meters exist now, although MnDOT's web site could probably tell you. They have data on the study and its aftermath on their web site.