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Avoiding Red Lights By Booking Ahead
RedEaredSlider writes "Peter Stone, associate professor of computer science at the University of Texas at Austin, has presented an idea at the AAAS meeting today for managing intersections: a computer in a car calls ahead to the nearest intersection it is headed towards, and says it will arrive at a given time. The intersection checks to see if anyone else is arriving then, and if the slot is open, it tells the car to proceed. If it isn't, it tells the car that the car remains responsible for slowing down or stopping. He says that even with only a few connected cars, the system still works, even if the benefits are still only to those who have the connected vehicles."
...before arriving at the light? How far ahead are they "booking" a slot? How long until the slot becomes available if the car with the reservation isn't going to arrive. This really only sounds useful in more rural areas. I can't see a city with lights on every block being able to implement this technology with any kind of efficiency.
There are induction loops (metal dectors) buried in the pavement that tell the traffic lights about approaching cars. When my car passes over the loop it is telling the traffic signal at the intersection that I will be arriving within 10 seconds. If there is no cross traffic the light tells me to proceed by changing to green (or remaining green).
Any time you are driving on surface streets (hate that term), you soon learn to "drive the stop-lights" by looking ahead a block or two. Its
not that hard, and even when you can't see the lights driving just about the speed limit will be close enough to get you 5 greens out of 6 tries.
That being said, anything that can guarantee more greens is welcome, but putting it in cars seems the wrong approach. If the stop lights just
talked to each other you would have enough info. When Stoplight A can't clear its queue in the allotted green, you can pretty much bet stoplight B won't be able to do so when that slug of cars reaches it.
In most cases the problem is dumb signals, hold overs from the Pleistocene, with no attempt to make traffic efficient.
Sig Battery depleted. Reverting to safe mode.
Why not just use smart phones it'd be just as simple to attach the correct sensor or it may be able to use the gps most of them already have.
Tell that to the people in my neighbourhood who don't have a clue how to deal with a roundabout.
If the light doesn't have a slot knows there will be one available just a bit later, the light can signal the car to coast down from 45MPH to 35MPH, arriving just a bit later. By doing so it reduces the energy lost into the brakes and the car ends up coasting through the intersection on the green light instead of stopping and then having to restart just a few seconds later.
You can do this manually by paying attention to what's going on in the next several stoplights. It saves gas and brake wear. It's kind of nice just cruising along and hitting all the lights. Getting feedback from the light would make it much more effective.
Unfortunately it also drives some drivers crazy. They can't stand it that I'm going 35MPH in a 45MPH zone and go racing past... Just to end up stopped at a stoplight which then turns green a few seconds later and I go drifting on past. And still they don't get it.
Scary, isn't it. We had a roundabout put in one of our major intersections about a year ago (to much wailing and rending of garments). Perhaps 90% of drivers picked it up in the first few weeks. The other 10%, well, all I can say it's a shame that speeds are so low that we'll never get rid of them via traffic accidents. We just have to find some better way.
Nobody really liked my idea of putting forks in some power outlets to see who would pull them out.
Faster! Faster! Faster would be better!
Perhaps things are different in Texas, but where I live the majority of traffic lights and stop signs are installed for the express purpose of impeding the flow of traffic. Trying to sell them a sensible system to improve traffic flow, reduce pollution and ticketable offenses is the last thing they'd be interested in.
One source says there are less then 1200 roundabouts in the UK.
A slide in some American organisation's powerpoint presentation. It's ridiculously wrong.
There are 66 cities in the UK. That figure would mean just 18 roundabouts per city. If you forgot about all of the ones on the motorways and A roads in the countryside and towns. Which anyone who knows the UK can see is stupidly low.
Heck Milton Keynes alone has around 300 roundabouts, and thats only a town, not a city.
There doesn't appear to be any count of the number of roundabouts in the UK. There are far too many to count.
There's not really any reason to second guess why that powerpoint slide has it so wrong. But just for the hell of it... I guess they asked the UK Highways Agency. Which only maintains motorways and major trunk roads. Most roads and therefore roundabouts are under the jurisdiction of local councils. It's kind of like the difference between the US federal government and individual states and counties.
...but only for public transport!
My wife worked for 9 years optimizing public transport in Oslo, Norway.
One of the key items behind a significant speedup for both buses and trams was a system where each vehicle would signal ahead a given distance before arriving at an intersection, again as it entered, and finally as it left. If you visit Oslo and sit up front in a bus or tram you can see the visual feedback the driver gets: A single white LED mounted near the top of the traffic signal will light up, either blinking or in a steady state.
There is (of course) a web site and a mobile app which will give you real-time information about any given bus/tram/line/stop, as well as rolling displays at all major stops that show the same info.
http://trafikanten.no/ and http://m.trafikanten.no/
Terje
"almost all programming can be viewed as an exercise in caching"