Validating Availtec’s Bus Arrival Estimates

In my last post, I created a dashboard that shows the estimated arrival time of buses at specific stops. After using it, I was curious to see how accurate those estimates are.

So I have created a new project:

availtec-estimate-validation

As always, everything is opensource and available on my github page.

This project consists of two parts:

  1. A capture script that queries Availtec’s API every 30 seconds for the estimated arrival time and stores them in a local database
  2. A graph script that generates pretty visualizations from the captured data.

Here is an example of the Route 44 Inbound at St. Vincents Hospital for Birmingham, AL’s transit system.

Route 44 Estimates

Each “block” is a bus trip throughout the day. The dark black line represents the actual time the bus arrived at this stop. The dark blue line shows when Availtec estimated the bus would arrive at that specific time.

Ideally, the dark blue line would be as close as possible to the dark black line.

From the image above, we can see that the 4th trip, from 10:44:17 to 10:46:17 had the best estimate. From 10:00am to 10:50am, Availtec estimated the bus would arrive ±30 seconds from when it actually did.

We can also see that the trip after it, had the worst estimate. From the time the trip started, just before 10:50, until around 11:20, Availtec was estimating the bus would arrive at 11:32, when it actually came at 11:38. It wasn’t until about 11:25, that the system suddenly corrected and started estimating a more realistic time.

This project works with any bus system that utilizes Availtec for real time tracking. You can leave the capturer program running in the background for days, then generate graphs based on that historical data. The graphing script allows you to specify which stops, routes, and days to plot.

Announcing Montclair for iOS and Android

I have taken my Montclair bus tracking web site and created an App for both Android and iOS that you can download for free in their app stores.

The app was not found in the store. 🙁

Montclair
Montclair
Developer: line72
Price: Free

This came about because I have been unhappy about how iOS handles progressive web apps. Every time the app is brought to the foreground, iOS does a full reload, which can be slow and annoying. The native app handles this much nicer, and doesn’t ever have to reload the state.

To build the native apps, I used this handy tool: Progress Web App Builder. It takes your website, wraps it using Cordova, and generates both an iOS and an Android project. With only a few tweaks, I was able to get them submitted to the app store.

Real time tracking of Birmingham’s Bus Systems

Birmingham, Alabama’s transit agency, the BJCTA (Birmingham-Jefferson County Transit Authority) has a website for tracking the buses in real time. This website along with their mobile app are ok, but have some things that constantly annoy me. My biggest annoyance is that every time the App is brought to the foreground, it refreshes and resets you back to the main page, losing the bus you were trying to track. The other problem is that you can only view one route at a time (at least on the mobile app). I have 3 routes that I can choose between every day. When I open the app, I want those three routes selected by default so I can quickly see which route to pick.

With that, I present to you Montclair.

Montclair is a simple javascript application written in React. The version running at https://montclair.line72.net supports both the official Birmingham Transit System and the University of Alabama at Birmingham’s transit system. However, the code is not tied to any specific transit system and will actually support any real time system powered by Availtec or TransLoc. As always, everything is open source:

Visualizing the On Time Performance of Birmingham’s Bus System

A few months ago, Birmingham, Alabama’s bus system (BJCTA Max Transit) retrofitted all of their buses with a GPS system. Along with this upgrade, they released a website allowing riders and the public to track the locations of buses in real time. The website is backed with a public RESTful API, so I decided I would poll the API to retrieve live information on all the buses throughout the day and store them in a local database.

With this information, it is possible to run some analysis on the system. We could look at passenger count, travel time, travel deviation, areas where buses tend to slow down, performance at different times of the day, and a host of other analytics.

The first analysis I have done is looking at the time deviation. This is how far ahead or behind schedule a bus currently is. A negative number means it is ahead of schedule and a positive number means it is behind schedule. The general rule is that ± 5 minutes is “on time”.

The graph below goes through an entire day looking at all the buses on each route. Each route is separated into its own section, so you can clearly see how a single route performs throughout the day. Along a route, multiple buses will simultaneously be making individual trips along that route. Each color represents a different bus making a different trip. Since there is overlap between buses sometimes making it difficult to see where a trip starts and ends, I have placed bars below the graph. Each of these bars mirrors a single bus making a single trip, allowing you to easily see how many active buses there are and when they started and stopped their trip.

 

If we zoom into a specific route, we can get more detail (Click on the image to see the full day). This is line 17 – Eastwood Mall. It is one of the busier routes with several buses making simultaneous trips. As you can see, most trips start and end on time, however, there is a bit of a peak about halfway through the trips, where the bus is behind schedule by up to 15 minutes.

After looking through the data, I have few interesting conclusions:

  • There is quite a bit of deviation along most routes. However, the most important thing to look at is the start and end of each trip, and for most trips, those have a tendency to converge on 0 deviation. This means the overall trip length is as expected, but buses are being held up in the middle of trips due to traffic and other unforeseeable circumstances.
  • I don’t know what happened to the 14 (Idlewild Palisades) around 5pm. I’m thinking the bus broke down and a new bus (purple) had to be sent out to replace it.

  • Some routes are interlined. For example, the 12 and 18. The bus starts off as the 12, does its trip, but once it pulls into central station, that same bus becomes the 18 and does a trip along route 18. When it returns to central station, it once again becomes the 12. It appears as though the 18 is constantly taking longer than the expected time which makes the 12 start late. Even though the 12 makes up time, it can’t seem to ever get on schedule.

  • The 280 runs down a major suburban corridor that has the worst traffic in the region. Even during rush hour at 5.00pm, the route is expected to have the same trip time as 10am. Clearly it doesn’t.
  • The most heavily used routes: 17, 1, 3, 44, 45, 6, 28, 8, 1 Ex all have minor deviation and run on time.

The code is currently available on github:

https://github.com/line72/dv8

I’m still cleaning up the code, but it is currently usable. I’m also thinking about porting this to D3 and doing live visualization on a website rather than generating a static image.

BJCTA Trip Planner now in sync with official data

My trip planner for the BJCTA Max buses (http://www.bjctatripplanner.org) along with my android app, are now in sync with the official data from the BJCTA. I will continue to keep my site in sync with their data, which means up to date and accurate data!

The app was not found in the store. 🙁

Weld Article On The BJCTA Bus System

Weld recently did a two part series on the status of the BJCTA Bus System. My trip planner was featured in the second part. You can read it online from the links below:

Part 1
Part 1

Part 2
Part 2

Part 1 is a very interesting look at the decline of the bus system since the 1950s and the turmoil and political games around transit in Birmingham. Part 2 takes a look at what is being done now to improve the system along with stories from riders who rely on the system.

Sightings of My App

Last night I was waiting on a bus in 5 points after some drinks with friends. Among the 12 of us who were waiting on a bus, I noticed two young girls, who we clearly not from Birmingham, looking at their phones to figure out what bus to ride to get back to their hotel near the convention center. As I looked over their shoulder, I saw they were using my App! That right there was enough to make me realize that all the work I’ve been doing for the last 1.5 years has been worth it! So, if you haven’t already, give the buses a try and use my app to help you.

 

BJCTA Bus Trip Planner

The app was not found in the store. 🙁

The app was not found in the store. 🙁