I mean this wouldn't really work because it really optimizes one mode of travel (the car) at the expense of nearly everyone else. People still need time to cross the street on foot or on a bicycle.
It's hard to tell exactly what the article is arguing for. I don't know what the status quo on traffic control is for Mexico City.
I know some big cities have all their lights on a set schedule. Some big cities have a fully integrated system where intersections communicate and predict arrivals to one intersection based on exits from another.
I think the researcher is suggesting that prediction is too difficult to make good results from fixed scheduling or communicating intersections, and that instead, each intersection should adapt to its local sensors. That can include bike detectors and pedestrian buttons.
I think this idea generally works. I've seen lots of traffic signals that respond to cars, bikes, and pedestrians (via button, sadly, I've never seen an inductive loop detector in a sidewalk, would have to be sensitive to count a person). You get better results if you can put sensors a bit back from the intersection to determine queue length, although that adds some expense. It's also nice if traffic controls can be placed into an event mode to help traffic disperse from things like sporting events, commuter trains, and ferries; at least for a few intersections around the site, adaptation may not be enough if there's steady cross traffic, during the event, it may be more efficient to make cross traffic wait longer than normal reasonable limits, or add a cycle for all direction walking, so pedestrians can make diagnol crossings more easily, etc.
Cars idling at a stop light when there's no conflicting traffic (including bikes and peds) is bad for everyone, not just cars. Reducing that is good for everyone, at least in the small --- as the article mentions, improved traffic conditions may encourage more driving, which may not be beneficial for bikes and peds.
I agree intelligent traffic lights that prevent needless waiting would be awesome. I guess in part it becomes a liability thing.. what if the sensors don't detect a child and there is an accident. The city probably doesn't want that liability
If I remember correctly, some types of pedestrian crossings in the UK actually use sensors to automatically detect people waiting near the lights (and also detect if they're still around, or have actually crossed/otherwise disappeared before the pedestrian phase [1]).
If you want to do more than that, i.e. detect pedestrians before they actually reach the crossing, the problem is that pedestrians don't have turning lanes, so it's hard to tell which way people approaching the crossing actually want to turn.
[1] If I'm not severely misremembering things, one thing I like about UK traffic regulations is that it's not actually illegal to cross against a red light as a pedestrian if you're not obstructing anybody. Obviously if there's an accident you're going to be liable if you crossed against a red light, but if the road is clear and nothing happens you cannot be fined.
>one thing I like about UK traffic regulations is that it's not actually illegal to cross against a red light as a pedestrian if you're not obstructing anybody.
Correct "jaywalking" is not a thing here and I think there'd be an uprising if it was.
>Obviously if there's an accident you're going to be liable if you crossed against a red light
Even this is not blankly the case, quite often it would return a split liability result [1], some recent examples [2] are infuriating.
you sound like you have some expertise on this, so I would like your opinion on the following: on my street they have put up signs that display how many seconds it is to the light shift at the cross walk, ostensibly for bikes, but totally readable by cars - it's about 4 houses to the light. It struck me as being idiotic and wasteful for the environment to have made this sign and to use the electricity to power it, but also I would think there would be side effects to the traffic flow that would actually make the sign counterproductive - do you know what the usefulness of these signs is?
I'm just an observant amatuer, no professional traffic experience, although, someone linked a manual for LA's traffic management system (it's a commercial system, but the manual is customized for LA), and reading through some of that confirmed the observations of capability I've made over time.
I haven't seen a time until green? (or is time until yellow/red?) sign like that personally, so I'm not sure about usefulness. I'd imagine electricity cost is pretty negligible, assuming LED lighting etc.
I used to drive frequently in areas with countdown timers for pedestrian cycles; if the vehicle cycle was also ending, the vehicle light would turn yellow when the pedestrian signal hit zero. As a driver in the opposing direction, seeing the countdown helped me decide if I wanted to wait for the signal or make a right turn on red (if conditions permitted). As a driver in the direction of the countdown, it let me plan for a yellow, and I think I was able to make better decisions about stopping or going on yellow; I imagine some drivers might take the countdowns as a queue to speedup to make the light, anecdotally I didn't see that, but you'd need real numbers to decide.
Anyway, if the approach to the intersection is a downhill, as a cyclist, it's nice to know earlier if I need to brake or not, or if I could make it through if I pedal a bit. If there's enough bike traffic to support that, it sounds nice. I don't think you could signal to bikes and not cars --- at least where I've riden, bicycles at reasonable speed are vehicles and should travel in vehicular lanes unless a restricted lane is available and appropriate (bike lanes are restricted to bikes, but bikes are not restricted to bike lanes). Given that, I don't know how you'd signal to cyclists and not car drivers.
Ok, but it really looks like it is placed for the benefit of cyclists coming down the hill of the street. Also it is far enough back that when you are waiting for it to turn green you can't see it.
