Stuck at the lights

by on Jul.18, 2012, under Everything, Smart Traffic

Douglas Adams once observed that intelligent aliens traveling to  Earth might assume from their surveillance that the car was the superior form of life on the planet.  I think he was almost right, though I suspect they would mistake the traffic light as the top of our planet’s pecking order, as the pulse of life in every major city is defined by the commands issued from these oligarchs.

They are however really pretty stupid.

Many times I have sat in a line of traffic waiting for the green in spite of there being no other traffic using the intersection.  On these occasions I wonder that surely there must be a better way.

It turns out there are efforts being made to make Traffic Lights ‘Smart’, and these typically centre on efforts to connect cars via wireless technologies (wifi, 3G etc) to each other and to a central network.  Such a world would usher in a huge host of attending benefits:

  • Predictive braking, so when the car in front puts on the breaks it announces to all cars following which then disengage the accelerator and start braking in anticipation of the driver doing the same
  • Faster Emergency Responses as all cars on a stretch of road are warned via the network of an approaching emergency vehicle and can then warn the driver where to go to get out of the way – even before the lights or siren get in range
  • Less traffic strain on existing roads, since due to predictive braking cars can travel closer together allowing for higher traffic density
  • Better incident management, as traffic data is captured in real time allowing for identification and immediate management of trouble spots
  • More effective infrastructure planning, due to highly granular traffic data

While this is all great and brilliant, of course the realisation of the above technology is greatly hampered by the huge number of industry participants and the lack of any standard or leadership in the area (efforts by BMW and Siemens notwithstanding).  Experience from other similarly fragmented industries tells us that it will take years before a single technology is adopted broadly enough to make it worthwhile.

In the meantime however there is an opportunity to make traffic lights smarter even though cars are still dumb.  Every traffic light installation today has a basic level of intelligence; induction coil sensors in the road pick up the presence of cars waiting at the intersection and inform the timing pattern of the lights such that while no cars are waiting on a crossroad the default route gets the green a little longer.  I can see an opportunity to improve on this behaviour in two ways.

  1. Link sets of lights.  By providing a set of lights (A) with data about cars passing over sensors at an adjacent set of lights (B), lights A can anticipate traffic coming their way and better time cycles of changing lights.  This approach requires some physical networking of light sets and re-tooling of traffic light algorithms however would result in a significant (>10%) improvement in waiting times, carbon emissions, general sanity etc
  2. Give traffic lights the power of sight.  There has been much advancement in the technology of video object recognition, much of this due to investment in devices such as Microsoft Kinect and Google’s Goggles.  Which the idea suggested above at (1) would provide traffic lights with a degree of better visibility of coming traffic, equipping lights with cameras and the means to understand what they are seeing would allow a greater resolution and overcome limitations inherent in a sensor only solution – such as recognising and responding to bikes, pedestrians and traffic incidents.

The second solution has the potential to allow for even greater granularity in traffic management.  Imagine waiting at a quiet intersection in the future where the lights give green signal just long enough for you to get through before the next wave of traffic approaches.  There is room for highly significant improvements in traffic flow rates with such a setup, although it would have to take into account driver response times for starting and stopping.  It also provides the benefit of additional sets of traffic cameras for transport authority monitoring of roads and incident recording.

Since the light cycle times become more granular in this solution it is important that drivers understand that they are being allowed to proceed under a smart lighting scenario; effectively they must not delay when moving through the intersection, as well as be alert to oncoming traffic. To signal this I introduce a new colour light located below the green. The flashing blue light indicates it is safe for a single car to proceed through the intersection without delay.

The beautiful thing about the smart traffic light solutions I’ve suggested is that no industry concordance is needed in order to make them work;  a suitable technology solution from any player can be implemented by any forward-thinking council anywhere.  It might become obsolete in 10 years when smart cars become predominant on our roads, but by then the solution would have paid for itself many times over though reduced investment in new roads and lower carbon emissions.

Something to think about next time you’re stuck waiting at the lights…

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