Moving People: Transit-Oriented Design#
SLOP2418 — Urban Design Studio
Week 5 · Idris Fenn · 22 March 2027
direct readout · derived measure · worked hypothetical
A standing position, stated up front#
The first network you draw is a diagram of your assumptions. It is not yet a plan. The fastest way to find out which assumption is wrong is to run it at eight in the morning and watch where it fails.
— the tutor, every year, at this point in the semester
The argument#
A line nobody can read at a glance, or wait for without planning around it, is a line nobody rides.
Calthorpe, 1993#
Intensity follows the stop only when the walk to it remains continuous.
Two ways a stop fails#
- No catchment. The stop is inside the walk of 900 people. It will carry the trips of 900 people, which is not a line, it is a subsidy.
- No legibility. The stop is inside the walk of 9,000 people who cannot tell you where the line goes. It will carry the trips of the ones who have already worked it out.
- The first failure is a zoning problem and takes a year of simulated time to fix. The second is a geometry problem and takes an afternoon.
- Students overwhelmingly diagnose the first and have the second.
Lynch on the parts and the whole#
Nothing is experienced by itself, but always in relation to its surroundings, the sequences of events leading up to it, the memory of past experiences.
— Kevin Lynch, The Image of the City (1960)
Lynch’s five elements, as a transit network#
| Lynch’s element | In the network | Design consequence |
|---|---|---|
| Path | The line itself | It should read as one movement, not a sequence of detours |
| Node | The interchange | There should be few, and each should be obviously an interchange |
| Landmark | The terminus and the depot | Name the ends of the line after places, not after directions |
| Edge | The Kerrow corridor, the rising ground at Denton Hill | Lines that cross an edge need a reason; lines that follow one are legible |
| District | The station area itself | The 600 m circle is the thing the line is for, and it should look like it on the ground |
Frequency is freedom#
The Denton Hill–Barrow Fields line. Round-trip running time, including layover: 24 minutes.
| Headway | Average wait (half the headway) | Vehicles required | Monthly operating cost |
|---|---|---|---|
| 30 min | 15.0 min | 1 | 1,150 |
| 15 min | 7.5 min | 2 | 2,300 |
| 10 min | 5.0 min | 3 | 3,450 |
| 5 min | 2.5 min | 5 | 5,750 |
Vehicles required = round-trip time ÷ headway, rounded up.
What a headway is worth#
- Below about a 12-minute headway, riders stop consulting a timetable and start turning up. That change is worth more than the minutes it saves.
- Above about a 20-minute headway, the line is planned around rather than used, and its ridership becomes a function of how few alternatives exist.
- The Transportation Overview reports waiting passengers per stop. A queue that never clears is not demand, it is a fleet shortage, and the two are marked differently.
- The operating cost does not fall when ridership falls. It is the one line in the budget that is indifferent to whether the service works.
The arithmetic of the transfer#
Two ways from a dwelling on Pelling Street to a workplace at Barrow Fields. Out-of-vehicle time weighted at 2.5, after Vuchic.
| Measure | Route A: one seat | Route B: two seats |
|---|---|---|
| Walk to stop | 5 min | 5 min |
| Initial wait | 5 min | 5 min |
| First ride | 22 min | 8 min |
| Transfer wait | — | 6 min |
| Second ride | — | 7 min |
| Walk to work | 3 min | 3 min |
| Actual journey | 35 min | 34 min |
| Out-of-vehicle total | 13 min | 19 min |
| Perceived journey (in-vehicle + 2.5 × out-of-vehicle) | 54.5 min | 62.5 min |
Stop spacing, from the same arithmetic#
- Every stop added shortens somebody’s walk by up to 200 m — that is 2.5 minutes of walking, weighted, worth about 6 minutes.
- Every stop added lengthens everybody’s ride by roughly 25 seconds of dwell and deceleration.
- On a line carrying 900 riders past a stop used by 40, the arithmetic resolves against the stop.
- Which is why the coverage question cannot be settled stop by stop. It has to be settled for the line.
Ridership or coverage#
A six-stop bus from Denton Hill to Barrow Fields: legible, frequent, measurable.
The tradeoff of the week#
Mobility performance against fiscal performance.
Every vehicle you add buys wait time back for every rider on the line, and commits the district to that vehicle’s upkeep for as long as the line runs.
What this work feeds#
- No weighted assessment is due in Weeks 5 or 6; upload each weekly save and evidence sheet by 21:00.
- Keep the before-and-after traffic and transit evidence: mobility performance is marked again in Assessment 2 in Week 9 and in the Week 12 capstone.
- Assessment 2 is the Public Realm and Infrastructure Plan, due Week 9, worth 25%.
This week’s studio, and next week#
Monday is the transit studio. Bring the Week 4 personal save and issued transit baseline. Record the before readings, then draw and fund the transit line and justify its headway. Do not widen Wickstead: the road intervention belongs to Week 6. Preserve the pre-widening save and upload the transit sheet and weekly save by 21:00. Follow the studio brief.
Week 6 tests the road widening against the saved transit baseline.