5 ms·
The cited research exploring potential weaknesses in the Vehicle-to-Infrastructure standards seems worthwhile, in part because the primary entities (auto makers
by mrandish 2y ago
The cited research exploring potential weaknesses in the Vehicle-to-Infrastructure standards seems worthwhile, in part because the primary entities (auto makers and a government agency) aren't exactly known for robustly secure early implementations of new emerging technologies.
More broadly, the area of roadway infrastructure tech brings up a pet peeve of mine. The street I live on ends in a T-intersection with a traffic light onto a main thoroughfare in our mid-sized suburb. The cross-traffic on the main thoroughfare can be quite dense but only during peak commute hours. Understandably, the wait for the green arrow to turn left onto our street is quite long after triggering the in-road sensor because it's stopping a lot of traffic which they don't want to do too frequently. Late at night the wait timer is set much shorter since there's very little oncoming traffic. However, quite consistently, there are other periods with equally little oncoming traffic, such as a couple hours every weekday mid-morning and mid-afternoon.
This leads to residents in our neighborhood waiting three or more minutes to turn left in the middle of the day when there aren't even any oncoming cars to stop, and often no cars at all on the thoroughfare within half a mile. Regularly leaving turning cars idling for so long when no other cars are even in sight is environmentally wasteful as well as super annoying. I assume a Raspberry Pi-level SBC with a camera could easily make the traffic signal efficient for cars waiting to turn left without adding any delay for oncoming traffic over the current timer system (or digging up roadway for more sensors).
In this not-uncommon scenario, the "smart light" doesn't need to even be that smart or bullet-proof since it can always fall back to the basic timer if the situation isn't clear and can be gated at the other extreme by a max frequency limit for acting. Which is why I'm puzzled I don't see any such solutions deployed anywhere. It seems like a simple way to improve worthy metrics that's easy to deploy, low cost and has no downsides.
- rdn 2y agoSome intersections have a sensor under the asphalt to detect a vehicle and sequence a light transition, and its not a new technology
- jamiesonbecker 2y agoThat's not what the article is talking about.
- mrandish 2y agoYes, this intersection has that. The problem is the sensor starts a timer that's set to 2 or 3 minutes for most of the day. This becomes a minimum wait time even when there are no oncoming cars for the entire wait period. At this intersection, the wastefully pointless "idle there for 3 minutes with no other cars anywhere in sight" scenario happens quite often. There's also an even more perverse failure mode: we often end up waiting for 2.5 minutes with no other cars anywhere in sight, then when a lone car is randomly approaching the light that's been green for no cars (going its way) for 2.5 minutes, that one car gets stopped and waits as we finally get our turn arrow after 3 minutes. If the light was the least bit "smart", it would have changed for us right when we pulled up and no other cars were in sight. The turn arrow is only 10 seconds, so we would have been long gone and the intersection back to green by the time that other car was approaching - no car would have needed to wait and everyone would have been better served.
- Filligree 2y agoThere's a few intersections like that here in Dublin. But they aren't marked. So what sometimes happens is I cruise up on a bike, in the middle of the road because none of those have bike lanes.. and the bike, naturally, never triggers the lights. Neither does the car behind me.
- doubled112 2y agoI used to make note of these and run up to push the pedestrian crossing button if there was one. It is the only way the system will realize you are waiting.
- mrandish 2y agoSorry to hear it's not only a problem here in the U.S. Ideally, our intersection wouldn't have dedicated left turn arrows at all, since it doesn't need them most of the day. The problem arises only about four hours a day. At those times the otherwise empty thoroughfare turns into a wave of cars making it impossible to enter or leave our neighborhood street by turning left because there's rarely a large enough gap in the fast-flowing traffic. Traffic engineers probably have a term for this kind of bi-polar intersection. A solution would be some kind of "conditional left arrow" but there's no such thing (at least here in the U.S.) If there's a dedicated green arrow for left turn, then there's a modal left-turn red arrow along with it. It should be possible to improve all scenarios by standardizing something like a flashing yellow arrow to mean "okay to cross if no oncoming traffic" since this already works as the default behavior at intersections with no lights or lights with no left turn arrows.
- quickthrowman 2y agohttps://en.m.wikipedia.org/wiki/Induction_loop https://en.m.wikipedia.org/wiki/Induction_loop