Welcome back to my NYTIP series! In my updated South Brooklyn redesign post, I proposed a J extension to Bay Parkway. How would that extension affect J service in North Brooklyn and Queens? I will discuss that in this post.

Note: Click any image to enlarge.

Present-day J/Z skip-stop service dates back to the Archer Avenue subway’s opening in 1988. The purpose of the skip-stop service was to establish the J/Z as a faster alternative to the overcrowded E line for service to Lower Manhattan. J and Z trains ran every 10 minutes each, leading to combined service every 5 minutes at stations served by both J and Z trains. The skip-stop pattern operated for about one hour in each peak direction during rush hours.

[Fig. 1] Overview of the J/Z skip-stop service.

Neither the span of skip-stop service nor the frequency have changed much in the last 34 years. The only significant change aside from construction-related suspensions and station/line closures was an added stop at Alabama Avenue on the Z in 2014 to accommodate NYC Transit employees working in East New York Yard or the adjacent bus depot.

Is Skip-Stop Service Still Worth It Today?

With transit advocacy rightly focusing on service increases (see, for example, the Riders Alliance Safety Plan which reiterates the need for minimum 6-minute service), is the J/Z skip-stop service still worth it today?

Time Saved v. Time Wasted

The main selling point of the J/Z skip-stop service is time saved. So how much time does it save, anyway?

The J/Z skip-stop service operates between Jamaica Center in Queens and Myrtle Avenue in Brooklyn. J and Z trains both stop at Jamaica Center, Sutphin Boulevard – JFK, Woodhaven Boulevard, Crescent Street, Alabama Avenue, Broadway Junction, and Myrtle Avenue; these stations see combined service every 5 minutes. The other stations between Jamaica Center and Myrtle Avenue only get J or Z service every 10 minutes; as Figure 1 shows, the J skips 7 stops and the Z skips 6. Compared to all-local service, and given a time savings of approximately 30 seconds per station skipped, the J saves about 3 1/2 minutes and the Z saves 3 minutes. However, these time savings are measured from Jamaica.

From Woodhaven Boulevard, both J and Z trains save approximately 2 1/2 minutes. Further west, the cumulative time saved decreases. The time saved by skip-stop service is offset by long wait times at the skipped stations; with a train every 10 minutes, the average wait is 5 minutes. If the J/Z skip-stop were replaced by frequent J local service every 5 minutes, riders at skipped stations would save an average of 2 1/2 minutes of wait time, offset by the longer all-local ride. The table below shows all J/Z stations from Jamaica Center to Myrtle Avenue, the time saved by the current skip-stop service, and the net time savings (or loss) for frequent J local service.

Station	Service	Current Skip-Stop Time Savings (minutes)	All-Local Time Savings (minutes)	Net All-Local Savings or Loss (minutes)
Jamaica Center, Sutphin Blvd – JFK	J/Z	3 1/2 (J) 3 (Z)	0	-3 1/2
121st Street	Z	3	2 1/2	-1/2
111th Street	J	3	2 1/2	-1/2
104th Street	Z	2 1/2	2 1/2	0
Woodhaven Blvd	J/Z	2 1/2 (J/Z)	0	-2 1/2
85th Street	J	2 1/2	2 1/2	0
75th Street	Z	2	2 1/2	1/2
Cypress Hills	J	2	2 1/2	1/2
Crescent Street	J/Z	2 (J) 1 1/2 (Z)	0	-2
Norwood Avenue	Z	1 1/2	2 1/2	1
Cleveland Street	J	1 1/2	2 1/2	1
Van Siclen Avenue	Z	1	2 1/2	1 1/2
Alabama Avenue, Broadway Junction	J/Z	1 (J/Z)	0	-1
Chauncey Street	Z	1	2 1/2	1 1/2
Halsey Street	J	1/2	2 1/2	2
Gates Avenue	Z	1/2	2 1/2	2
Kosciuszko Street	J	0	2 1/2	2 1/2
Myrtle Avenue	J/Z	0	0	0

Compared to the current skip-stop pattern, all-local J service results in longer travel times at the “express” stops and even a few “local” stops east of 104th Street. However, west of 85th Street – Forest Parkway station, the frequent service becomes a net benefit at the “local” stops. But would all-local J service be a net benefit overall? Let’s dig deeper.

J/Z Ridership

The stations served by the J/Z have somewhat lower ridership compared to many other corridors throughout the city. Infrequent service at many stations is certainly a factor; however, in recent years, station renewals and other infrastructural work – not to mention the COVID-19 pandemic – have affected ridership. Therefore, to get a clearer picture of ridership patterns, I had to go all the way back to 2016. The chart below shows the 2016 average weekday ridership for the J/Z line from Myrtle Avenue to points east.

[Fig. 2] Bar chart of 2016 average ridership on the J/Z line. Source: MTA

In 2016, the “local” stations – those served by only one of the J or Z, had an average weekday ridership of 3,762 riders; in contrast, the “express” stations – those served by both J and Z trains – had an average weekday ridership of 7,697 – more than double the local ridership. (This figure only includes half of the ridership at Jamaica Center, Sutphin Boulevard – JFK, and Myrtle Avenue, and one-fourth of the ridership at Broadway Junction, since other lines serve these stations.) Based on these figures, replacing J/Z skip-stop service every 10 minutes each with J local service every 5 minutes would result in a net travel time increase of about 51 seconds per passenger per weekday.

It looks like the existing pattern is slightly superior. However, there is one important piece of this puzzle left to examine.

J/Z Line Commutation Patterns

Skip-stop service provides a maximal benefit to riders traveling between Queens and Manhattan, while J local service would benefit riders at several intermediate stations. Ridership figures are important in figuring out which pattern is best, but equally important is determining where that ridership is going.

To gain some insight into ridership patterns, I turned once more to OnTheMap. As with my South Brooklyn redesign post, I looked at the top 50 work destinations for riders living near the J/Z lines. (The latest data is from 2019.) I split this analysis into two parts – one for the Fulton Street/Jamaica Avenue corridor and one for the Broadway El between Myrtle Avenue and Broadway Junction. It’s a narrow-sense analysis, so the usual caveats (does not capture all ridership, does not capture leisure ridership, etc.) apply. Here are the results:

[Figs. 3, 4] Top 50 work destinations for J/Z riders on the eastern part of the Broadway El and the Fulton Street/Jamaica Avenue line, respectively.

In both figures, the usual suspects (Midtown, Lower Manhattan) stand out. But the differences between the two figures tell a story on their own.

For the Broadway El, there’s a higher concentration of Manhattan destinations; importantly, the Nassau Street corridor served by J and Z trains also contains several top destinations. Note that Industry City makes the top 50; this is one reason among several showing the viability of a J extension to Bay Parkway.

On the eastern end of the line (Fulton Street/Jamaica Avenue), a different picture emerges. There is a smaller concentration of Manhattan destinations and a larger concentration of Queens destinations (including Sunnyside, Forest Hills, Bayside, Jamaica Hospital, and LaGuardia and JFK Airports) – the latter being one of the top work destinations for this contingent. This suggests that there is nontrivial reverse peak ridership on this corridor.

Summary

Which service pattern makes the most sense for v1.0.0 v0.8.0 of the enhanced NYC subway? One can argue for both an improved version of the status quo and frequent J local service. One of the principal goals of the enhanced NYC subway under NYTIP is frequent service systemwide to the fullest extent possible. While the “obvious” solution is simply to increase J/Z service, there are several obstacles to this.

The Williamsburg Bridge crossing used by J, M, and Z trains currently has a capacity of roughly 24 trains per hour (TPH) combined. This limit, while potentially fixable with signaling improvements, is exacerbated by the at-grade merge between the J/Z and M trains at Myrtle Avenue. Since the M runs 10 TPH peak, this leaves about 14 TPH for combined J/Z service. However, even this is not possible due to the switch layout at the Jamaica Center terminus – since the switches are too far from the station, the entire J/Z line has a capacity of just 12 TPH. This is what MTA currently operates – albeit for just one hour in each direction.

In light of these constraints, along with commutation patterns along the J/Z line, v0.8.0 of the enhanced NYC subway implements frequent J local service in place of the skip-stop service. The Z would be eliminated. The J would run every 5 minutes during peak hours and every 6 minutes during off-peak hours; service through the Nassau Street loop to Bay Parkway would run every 6 minutes all day, while the extra J trains turn at Broad Street station. The J would still run peak-directional express service between Myrtle Avenue and Marcy Avenue stations in Brooklyn.

In the future, it would be necessary to address key constraints at Jamaica Center, Myrtle Avenue, and the Williamsburg Bridge to allow additional service increases. I’m mulling a few big ideas, which I will explore in future posts.