Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Transforming OpenStreetMap into thick roads and intersections

a-b-street.github.io

Post reply on HN
Print view View original

21–30 of 36 posts

Re: Transforming OpenStreetMap into thick roads and intersections

#21

Post by micromacrofoot »

anigbrowl wrote: post #15
takk309 wrote: post #12

I am a professional traffic engineer and I build micro-simulation models for most of the projects I am involved with. I can say that compared to software that is used in industry (PTV Vissim, PTV Vistro, and Trafficware Synchro) it looks like A/B is a reasonable toy model that can get pretty close to the real thing. I think it is great that software exists at a level for individuals without huge budgets to be able to…

What kinds of feedback does your profession care about? I am constantly frustrated as a pedestrian with the traffic flow and signal timing problems in my area but I feel like it's pointless to submit a complaint to my local municipality because my anecdotal data points will probably be disregarded. I'm not very good at nor patient for trying to do neighborhood people organization and go around in circles with City Ha…

I hate to say it, but the only thing that has ever worked for me is doing neighborhood people organization and going around in circles with City Hall for 5 years.

I have done some ridiculous things, including the "Shawshank Redemption" method of sending a letter every day until I get a response... I know my city counselor well enough to have literally eaten dinner in her home, and none of it worked. I've seen the neighborhood people organization method work faster than someone dying to fix inadequate traffic management.

Re: Transforming OpenStreetMap into thick roads and intersections

#22

Post by waits »

anigbrowl wrote: post #20
SECProto wrote: post #17

Earlier quoted context omitted.

I've lived a few different places, also working in transportation engineering. I personally care a great deal about accessibility, and would much rather delay cars slightly than pedestrians (for numerous reasons). For example, when reviewing traffic control plans, etc, I always make comments or suggest changes along those lines. But ultimately, it comes down to what the municipality wants to prioritize - unless there…

Thanks a lot for the feedback. I live near a traffic artery so I've always known there were trade-offs, but the frustration does mount after a while. My #1 beef is when the traffic is paused but you just missed the light change when you hit the ped xing button, and now it's not safe to rely on the light staying green while you dart across.

San Francisco avoids this particular problem by having the walk signal turn on automatically when the car signal is green — no need to hit a button (most intersections don't have buttons at all, and the ones that exist aren't even hooked up to the light).

I don't know if this would translate well to other cities — SF has a very pedestrian-friendly layout with narrow, slow streets , small blocks, and short light cycles — but it works well enough here that it might be worth trying elsewhere.

Re: Transforming OpenStreetMap into thick roads and intersections

#23

Post by smichel17 »

waits wrote: post #22
anigbrowl wrote: post #20

Earlier quoted context omitted.

Thanks a lot for the feedback. I live near a traffic artery so I've always known there were trade-offs, but the frustration does mount after a while. My #1 beef is when the traffic is paused but you just missed the light change when you hit the ped xing button, and now it's not safe to rely on the light staying green while you dart across.

San Francisco avoids this particular problem by having the walk signal turn on automatically when the car signal is green — no need to hit a button (most intersections don't have buttons at all, and the ones that exist aren't even hooked up to the light). I don't know if this would translate well to other cities — SF has a very pedestrian-friendly layout with narrow, slow streets , small blocks, and short light cycle…

When I visited Barcelona, I was struck by their intersection design. It's great.

Instead of squares, their streets intersect in diamonds, where the (largely one-way) streets come out of the corners. They're a bit larger than a square intersection-- it's like you took the square, and then filled in four right triangles at each of the corners.

The main effect is that crosswalks are significantly pushed back from the intersection center. As a pedestrian, there's far less ambiguity about where the cars are going (regardless of whether they use their signal). Same for drivers: you never have to wonder which way a pedestrian is gong to cross when they're standing at a corner where two crosswalks meet, because there are no such corners.

Of course, this also makes intersections much bigger. This is offset by having parking spaces along the edges of intersections.

Re: Transforming OpenStreetMap into thick roads and intersections

#24

Post by SECProto »

benrbray wrote: post #19
SECProto wrote: post #17

Earlier quoted context omitted.

I've lived a few different places, also working in transportation engineering. I personally care a great deal about accessibility, and would much rather delay cars slightly than pedestrians (for numerous reasons). For example, when reviewing traffic control plans, etc, I always make comments or suggest changes along those lines. But ultimately, it comes down to what the municipality wants to prioritize - unless there…

Can you or any other traffic engineers here tell me why we find it acceptable that cars are allowed to make unprotected left turns while pedestrians have a walk signal? Right turn on red is bad enough, but unprotected lefts give drivers a direct incentive to torpedo into crossing cyclists / pedestrians, as slowing down would mean a collision with oncoming traffic! Too many intersections in downtown Atlanta, for insta…

Most North American road infrastructure has been rebuilt over the last century to be automobile-centric. "We" deem that conflict to be acceptable because the alternative is more complicated phasing - most of which results in delays to car traffic (and pedestrians!), and so most places won't accept it. For details, here's [1] a document that outlines the tradeoffs in various different signal phasing designs.

TL;DR is that "we" won't prioritize any road user except the automobile.

[1] https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter4....

Re: Transforming OpenStreetMap into thick roads and intersections

#25

Post by SECProto »

anigbrowl wrote: post #20
SECProto wrote: post #17

Earlier quoted context omitted.

I've lived a few different places, also working in transportation engineering. I personally care a great deal about accessibility, and would much rather delay cars slightly than pedestrians (for numerous reasons). For example, when reviewing traffic control plans, etc, I always make comments or suggest changes along those lines. But ultimately, it comes down to what the municipality wants to prioritize - unless there…

Thanks a lot for the feedback. I live near a traffic artery so I've always known there were trade-offs, but the frustration does mount after a while. My #1 beef is when the traffic is paused but you just missed the light change when you hit the ped xing button, and now it's not safe to rely on the light staying green while you dart across.

Yes, 'beg buttons' are awful (as are the 'red-revert' signal designs you allude to).

Re: Transforming OpenStreetMap into thick roads and intersections

#26

Post by jonas21 »

smichel17 wrote: post #23
waits wrote: post #22

Earlier quoted context omitted.

San Francisco avoids this particular problem by having the walk signal turn on automatically when the car signal is green — no need to hit a button (most intersections don't have buttons at all, and the ones that exist aren't even hooked up to the light). I don't know if this would translate well to other cities — SF has a very pedestrian-friendly layout with narrow, slow streets , small blocks, and short light cycle…

When I visited Barcelona, I was struck by their intersection design. It's great. Instead of squares, their streets intersect in diamonds , where the (largely one-way) streets come out of the corners. They're a bit larger than a square intersection-- it's like you took the square, and then filled in four right triangles at each of the corners. The main effect is that crosswalks are significantly pushed back from the i…

That might be great if you're visiting or just out for a stroll.

But let me tell you, it can be infuriating if you're walking to actually get somewhere. The city I live in has been replacing 2-way and 4-way stops with roundabouts, which has a similar effect of moving the crosswalks away from the intersection. Now it takes much longer to walk anywhere because you keep having to detour out of your way to cross the street.

Re: Transforming OpenStreetMap into thick roads and intersections

#27

Post by jerry1979 »

takk309 wrote: post #12

I am a professional traffic engineer and I build micro-simulation models for most of the projects I am involved with. I can say that compared to software that is used in industry (PTV Vissim, PTV Vistro, and Trafficware Synchro) it looks like A/B is a reasonable toy model that can get pretty close to the real thing. I think it is great that software exists at a level for individuals without huge budgets to be able to…

As someone with interest in traffic models, what spaces do you or your peers hang out outline?

Re: Transforming OpenStreetMap into thick roads and intersections

#28

Post by Dylan16807 »

> Highway on/off ramps https://a-b-street.github.io/docs/tech/map/geometry/index.ht...

It's hard to say which is better here, to be honest. A giant blob of gray is less helpful than showing some lanes, but the original version is much closer to the actual shape: https://www.google.com/maps/@47.6564275,-122.3223112,203m/da...

Though apparently even google can't handle this intersection. Where did the middle layer of road go, google? https://www.google.com/maps/@47.6556467,-122.3191587,69a,35y...

Re: Transforming OpenStreetMap into thick roads and intersections

#30

Post by 02020202 »

brings back memories. i was trying to make self-hosted maps(so you would not have to pay the absurd amounts of money for google or other map providers if you had bigger project. it worked very well but the OSM data, the system of tags, was such a mess that it was just not worth it. this guy obviously has a lot of time to waste. gl&hf.
Post reply on HN