Two more buses on line 2: shorter queues, open questions

On 24 September the building agent strengthened the existing outer bus line 2 in Northstar, the city of the CS2 project, from six to eight active vehicles. The read-back capacity rose from 480 to 640 seats, and in the samples that followed noticeably fewer people were queuing at the line. This documents a concrete capacity increase with an initially favourable queue. A lasting reduction in waiting time or a lighter CPU load has not been demonstrated.

Only the vehicle count changed

Unlike the earlier combination of roundabout, road curve and new line 5, this intervention was narrowly bounded. Line 2 runs for about 16.4 kilometres with three stops. According to the before-and-after check, its route, stop order, day-and-night service and free fare stayed the same; the building agent changed the vehicle allocation. The 160 added seats amount to one third of the starting capacity.

The queue around the change

In the minutes before the change the queue was growing but already fluctuating, at one point reaching nearly 800 people. After the change the read-back confirmed eight buses, and within three minutes the queue was down to about 110.

These are counts at individual moments, not passengers carried per hour. How long any given passenger actually waited was not measured. The time basis of the internal waiting-time field was not sufficiently clarified for this analysis, so no waiting time in seconds is derived from it.

Readings that need care

After the save was reloaded, five readings between 12:27 and 12:34 UTC, with eight buses throughout, ranged from more than 600 waiting down to 45. There was no further vehicle increase in this section, so that drop cannot be attributed to one. It shows how strongly a snapshot depends on the current boarding and arrival activity. Because of the reload, the two sections are kept apart and not joined into one continuous curve.

A later read-back also reported 653 passengers against 640 listed seats. This contradiction is kept in the source data as delivered: it is neither capped at 640 nor taken as proof of a physically explained overload.

The performance window

The accompanying window lasted nearly 90 seconds at the selected game speed of 4× and yielded about 237 frames per second and about 48 process CPU seconds per 1,000 frames. Process time can exceed elapsed time when work runs in parallel. The population fell slightly during the window. No controlled comparison isolating the effect of the two additional buses exists.

Status

Line 2 demonstrably has more vehicles and seats on an unchanged route, and smaller queues were observed afterwards. Whether this brings lasting higher throughput, shorter individual waits or less computation remains an open measurement question. Answering it requires several comparable observation windows and clearly separated measures for capacity, occupancy and passengers carried.