Frequently asked questions
Short answers first, with links into the methodology for the detail.
Is it free and do I need an account?
Yes, it is free and there is no account. Everything you set up lives in the page's URL: the Region centre, the radius and the random seed. Copy the link to share a run or to come back to it later; whoever opens it gets the same Road Network and, after pressing Start, an identical simulation.
Where does the street data come from, and why does my street look wrong?
The streets are OpenStreetMap, fetched live through the Overpass API and cached for 30 days. If a street is missing, one-way the wrong way or has the wrong lane count, the map is wrong: edit it on openstreetmap.org and the Region picks the change up once the cache expires. The methodology lists which tags the builder reads.
How realistic are the results? Can I use them for a planning decision?
They are a qualitative picture, not a traffic study. Each Vehicle follows the Intelligent Driver Model with published default parameters, so Queues, discharge rates and Spillback behave plausibly, but the Flows come from Road Class presets rather than counts, there is one lane per direction and no lane changing, and Signals run fixed-time plans. Use it to see where a Road Network tends to queue up and to compare changes; a decision needs a professional study with measured data.
What is a Bottleneck and how is the ranking computed?
A Bottleneck is a Segment or Intersection ranked among the most congested in the Region. Over the last ten simulated minutes, after warm-up, the engine sums the Delay charged to each one: time lost beyond free-flow, with Delay inside a Queue charged to the Intersection the Queue ends at. Rows are ordered by that total, and show Delay per Vehicle, speed ratio, Vehicles per hour, the longest Queue and whether it spilled back. Click a row to centre the map on it.
What does the colour of a Segment mean?
The colour is Congestion: the Segment's current mean speed divided by its free-flow speed. Green means 80 % or more of free-flow speed, yellow 50–80 %, orange 30–50 % and red below 30 %, smoothed over the last 30 seconds so a single Signal Cycle does not flicker the map.
Can I change traffic light timing or traffic volumes?
Yes. Click a Signal on the map to set its Cycle (30–180 s) and the green split between its two axes (20–80 %); the change applies at the next Cycle start. Click an Entry to set its Flow in vehicles per hour per lane. The Intensity slider scales every Flow at once, with night, normal and peak presets, and Reset replays the run from the same seed with your edits in place.
How big a Region can I simulate, and on which devices?
Up to 3 km of radius and 8 000 Vehicles on a desktop; 2 km and 3 000 Vehicles on a phone or touch tablet. The simulation runs in a Web Worker and the map in WebGL, so any recent Chrome, Firefox, Safari or Edge works. When the Vehicle cap is reached, new Vehicles wait in a virtual queue and the counter says so; if the simulation cannot keep up with the chosen speed, the HUD shows the effective speed.
Is my data stored or tracked?
There is no account and no cookie banner because nothing needs consent. The server sees the Region you load and the place names you search, which it forwards to the map-data providers; it keeps the built Road Network in a cache, not who asked for it. Usage statistics are aggregate and cookieless, never include coordinates, and can be switched off on the privacy page.
How does it compare with SUMO?
SUMO is a full microscopic simulator with lane changing, many vehicle types, calibrated demand and scripting, run on a desktop or server. transito-analyzer runs in the browser with one car-following model, one lane per direction and preset demand, and loads a Region in seconds. If you need a study, use SUMO; the methodology has a side-by-side table.
How do I cite or reuse results, and which licence applies?
Cite the page URL with the engine version shown on the methodology page and the shared link of the run, which fixes the Region and the seed. The street data is © OpenStreetMap contributors under the Open Database License, so any map or Road Network you reproduce must carry that credit. The source code and its licence are on the licences page.
Which languages are available and how do I switch?
Brazilian Portuguese, English and Spanish. Every page has a language switcher; the simulator keeps your choice in a session cookie. Nothing redirects you by location: the root address picks a language from your browser's preference once, and the language in the address always wins after that.
I found a bug or want a feature. Where do I go?
Open an issue on the GitHub repository linked in the footer, with the shared link of the run when the problem is specific to a Region: it fixes the Road Network and the seed, so the behaviour can be reproduced. Translation fixes are welcome there too: English is the source language, and Portuguese and Spanish start as machine translations until someone reviews them.