2.6 KiB
How A/B Street works
The big caveat: I'm a software engineer with no background in civil engineering. A/B Street absolutely shouldn't replace other planning or analysis. It's just meant to be an additional tool to quickly prototype ideas without expensive software and formal training.
This page gives a non-technical overview. See here for details.
The map of Seattle
The map in A/B Street is built from OpenStreetMap. You will notice many places where the number of lanes is wrong; let me know about these, and we can contribute the fix to OpenStreetMap. Many sidewalks and crosswalks are also incorrectly placed.
People in A/B Street have to park their cars somewhere. I can't find good data about either public or private parking. For now, I'm using a Seattle GeoData blockface dataset to guess on-street parking, but this is frequently wrong. I'm assigning every building one offstreet spot. This is wildly unrealistic, but I have nothing better yet.
There's also no public data about how traffic signals in Seattle are timed. I'm making automatic guesses, and attempting to manually survey as many signals in-person as I can. I could really use help here!
The traffic
Vehicles in A/B Street instantly accelerate and brake. They change lanes only at intersections, and they can't over-take slower vehicles in the middle of a lane. People walking on sidewalks can "ghost" through one another, or walk together in a crowd -- before COVID-19, this was a reasonable model in most areas. Despite these limits, I hope you'll find the large-scale traffic patterns that emerge from the simulation to be at least a little familiar from your real-world experiences.
People in A/B Street follow a specific schedule, taking trips between buildings throughout the day. The trips come from PSRC's Soundcast model, which uses census, land-use, and vehicle count data to generate a "synthetic population" roughly matching reality. The trip data is from 2014, which is quite old.
When you make changes to the map in A/B Street, exactly the people still take exactly the same trips, making the same decision whether to drive, walk, bike, or take transit. Currently, your changes only influence their route and experience along it.
Missing things
Light rail, shared biking/walking trails like the Burke Gilman, and ridesharing are some of the notable things missing right now.