UPDATE: Delay at Columbus and Green has cleared. The 8, 30 and 45 resuming regular service in both directions. https://t.co/g0xpJ6h8Ml (More: 22 in last 48 hours)
Information Gladly Given

NextMuni, Ghost Buses & Trains, Oh My!

Monday, November 24, 2014

In the last edition of Information Gladly Given, we tackled the subject of “NextBus,” better known to San Franciscans as “NextMuni.” Many customers learned why tracking their ride using the GPS technology isn’t flawless. In fact, there was a lot of feedback and questions that came out of the article and we want to let you know that we appreciate it! For those of you who may not have seen the blog comments, here’s a quick recap.

Ghost Buses & Trains
Have you ever been waiting for Muni and watching the minutes of the arrival predications count down only to have that vehicle not show up and the predictions disappear altogether? What a pain! Many refer to this phenomenon as a “ghost” bus or train. As a rider, you want to know that the bus or train that you are waiting for is really going to show up. We understand it’s a frustrating situation.

Ghost buses and trains happen when a train or bus is at the end of the line or terminal and not moving. Predictions from the terminal are based on scheduled departure times until the train starts moving, when predictions can be made on vehicle movement. If the train does not depart the terminal as scheduled, then the NextMuni system will drop predictions for the train after a few minutes and drop the subsequent predictions on the route.

The predictions will be inaccurate until the train starts moving again and the predictions can be provided accurately by the NextMuni system based on the moving train. Ghost buses and trains are usually caused by unforeseen circumstances such as Muni Operations needing to reassign the bus for an emergency on another part of the system, a mechanical issue or the route’s schedule being readjusted to help even out service.

Inaccurate N Judah NextMuni Predictions from the Ballpark
Ever been frustrated by “wildly inaccurate” arrival predictions for the outbound N Judah near the ballpark?

This is the basically the same issue as ghost trains. The Caltrain Station at 4th and King streets is the terminal for the N Line. Predictions from here are based on scheduled departure times until the train starts moving, when predictions can be made on vehicle movement. If the train doesn’t move on schedule for whatever reason (see above), then NextMuni gives the train a few minutes. If it still doesn’t go, NextMuni stops generating the predictions and waits for the train to be in motion before starting them up again.

Tracking Training Buses & Trains and How It Affects Predictions
Several people noted that they’d had difficulties because they’ve seen predictions for buses and trains that show up only to be out of service, such as a vehicle in training or pulling in for mechanical repairs. There are a few things going on here.

If a training bus or train is showing up in the NextMuni predictions, this is most likely because there’s a missing vehicle on that route and the NextMuni system automatically plugged the training vehicle into that time slot. We have been training more operators lately, which is good, but at the same time we need to make sure that training vehicles are correctly assigned in the system.

Some vehicles headed to the shop are actually in service. In order to provide NextMuni predictions to customers, the GPS is left on.

Another reason is simple human error. For example, if an operator is directed to return the bus or train to the yard ahead of schedule and forgets to log off the system while en route, the GPS info will be transmitted to NextMuni, which will continue to generate predictions. 

How Are NextMuni Predictions Generated for the Muni Subway?
In the subway, NextMuni predictions are based on the Automatic Train Control System (ATCS), which operates trains in the subway. The two systems coordinate for subway predictions.

Looking Forward
Muni is always working to make real-time predictions more accurate and works closely with NextBus to make improvements. The root cause of inaccurate predictions is unreliable
service caused by vehicle breakdowns, missing service, traffic, and construction detours. We are moving forward on major initiatives to improve service reliability. 

We are currently replacing and expanding Muni’s antiquated bus and light rail fleets to have more reliable vehicles and to make sure there’s enough room to accommodate current and future customers. We’ve also increased operator training and reduced gaps in service and those annoying predictions that jump around due to vehicles being reassigned.

In addition to adding vehicles and operators, we’re expanding transit priority throughout the city. Red transit-only lanes and signal priority, which holds green lights for buses and trains, help keep transit moving and make Muni more reliable.

Here’s what we’re looking forward to:

Information is always gladly given as we look forward to the future of transportation in San Francisco. A friendly reminder that for real-time service updates, sign up for email or text alerts,or follow SFMTA on Twitter @sfmta_muni for real-time service information 5 a.m. to 9 p.m., Monday through Friday. Feel free to ask us about NextMuni predictions for your route or line on Twitter. 

40 AM" attached to the aluminum structure of the transit shelter.