92% on timeof departures in the week ending 17 October 2026, leaving no more than 2.5 minutes early or 5 minutes late. Half of London's timetabled routes managed 73% or better.
Watch a day of route S4’s buses: every bus, replayed on the map. Or click a day on the chart.
The weekly figures
The share of departures that left on time.
| Week ending | Waddon Marsh Sainsbury's | Sutton / Marshall's Road |
|---|---|---|
| 21 Jun 2025 | no data | no data |
| 28 Jun 2025 | 67% | 82% |
| 5 Jul 2025 | 73% thin | 63% thin |
| 12 Jul 2025 | 62% thin | 90% thin |
| 19 Jul 2025 | 65% | 87% |
| 26 Jul 2025 | 68% | 86% |
| 2 Aug 2025 | 78% | 92% |
| 9 Aug 2025 | 62% | 83% |
| 16 Aug 2025 | 79% | 81% |
| 23 Aug 2025 | 48% | 74% |
| 30 Aug 2025 | 61% | 86% |
| 6 Sept 2025 | 52% | 71% |
| 13 Sept 2025 | 70% | 66% |
| 20 Sept 2025 | 70% | 74% |
| 27 Sept 2025 | 65% | 78% |
| 4 Oct 2025 | 68% | 74% |
| 11 Oct 2025 | 75% | 83% |
| 18 Oct 2025 | 81% | 86% |
| 25 Oct 2025 | 77% | 77% |
| 1 Nov 2025 | 64% | 83% |
| 8 Nov 2025 | 79% | 74% |
| 15 Nov 2025 | 77% thin | 76% thin |
| 22 Nov 2025 | 83% thin | 80% thin |
| 29 Nov 2025 | 77% | 82% |
| 6 Dec 2025 | 89% | 93% |
| 13 Dec 2025 | 91% | 96% |
| 20 Dec 2025 | 90% | 89% |
| 27 Dec 2025 | 85% thin | 94% thin |
| 3 Jan 2026 | 95% | 94% |
| 10 Jan 2026 | 88% | 92% |
| 17 Jan 2026 | 82% | 90% |
| 24 Jan 2026 | no data | 96% |
| 31 Jan 2026 | 92% | 98% |
| 7 Feb 2026 | 85% | 93% |
| 14 Feb 2026 | 93% | 88% |
| 21 Feb 2026 | no data | no data |
| 28 Feb 2026 | no data | no data |
| 7 Mar 2026 | 93% | 91% |
| 14 Mar 2026 | 93% | 94% |
| 21 Mar 2026 | 92% | 96% |
| 28 Mar 2026 | 91% | 95% |
| 4 Apr 2026 | 86% | 96% |
| 11 Apr 2026 | 90% | 96% |
| 18 Apr 2026 | 89% | 96% |
| 25 Apr 2026 | 94% thin | 94% thin |
| 2 May 2026 | 91% | 96% |
| 9 May 2026 | 94% | 94% |
| 16 May 2026 | 96% | 99% |
| 23 May 2026 | 93% | 90% |
| 30 May 2026 | 94% | 99% |
| 6 Jun 2026 | 91% | 96% |
| 13 Jun 2026 | 91% | 94% |
| 20 Jun 2026 | 97% | 95% |
| 27 Jun 2026 | 92% | 93% |
| 4 Jul 2026 | no data | no data |
| 11 Jul 2026 | 89% | 95% |
| 18 Jul 2026 | 88% | 94% |
| 25 Jul 2026 | 92% | 93% |
| 1 Aug 2026 | no data | no data |
| 8 Aug 2026 | no data | no data |
| 15 Aug 2026 | no data | no data |
| 22 Aug 2026 | no data | no data |
| 29 Aug 2026 | no data | no data |
| 5 Sept 2026 | 92% | 85% |
| 12 Sept 2026 | 83% | 89% |
| 19 Sept 2026 | 81% | 89% |
| 26 Sept 2026 | 92% | 92% |
| 3 Oct 2026 | 91% | 90% |
| 10 Oct 2026 | 88% | 92% |
| 17 Oct 2026 | 91% | 92% |
A passenger going by the timetable at Waddon Marsh Sainsbury's would find about one departure in ten leaving more than 2.5 minutes early or 5 minutes late.
- On time
- 91%
- Cut short
- 2.6%
- On time
- 92%
- Cut short
- 3.1%
96 minutes was the longest gap between buses this week, at Beddington Farm Road towards Waddon Marsh Sainsbury's, on Friday 16 October from 15:09 to 16:45. This excludes any gaps caused by holes in our own data. Watch it happen →
Journeys cut short
Last week: 2.1% of journeys were turned back before the end of the line in the week ending 17 October 2026. Everyone on board has to get off; for anyone waiting further along the route it's effectively a cancellation.
towards Waddon Marsh Sainsbury's
Last week, 7 of 277 journeys (3%) were turned short.
- Therapia Lane Tram Stop1.8 km short of the end 6
- Therapia Lane Tram Depot2.0 km short of the end 1
towards Sutton / Marshall's Road
Last week, 4 of 253 journeys (2%) were turned short.
- Belmont Station4.2 km short of the end 1
- Sutton Station1.6 km short of the end 1
- Beddington Lane / Sewage Treatment Works18.6 km short of the end 1
- The Newlands14.5 km short of the end 1
Each place is the last stop the bus was timed at before it turned round, with the typical distance it fell short of the end of the line. The five busiest are named; the rest are counted together.
Compared with TfL's own figures
| Quarter | TfL | Ours |
|---|---|---|
| 2025/26 Q313 Sept – 2 Jan 2026 | 77% on time | no figure |
| 2026/27 Q11 Apr – 26 Jun 2026 | 87% on time | no figure |
TfL's figures come from its own tracking equipment and its own timetable; mine are computed from the buses' public position feed. They are the same calculation on independent data, so they should broadly agree and move together rather than match exactly.
About this data
- Data collected, week ending 17 October 2026
- 100% of the week. This is the share of the week for which we hold bus location data at all, across the whole of London rather than for this route. A week under 60% is not published; under 90% it is marked as thin.
- Departures observed
- Waddon Marsh Sainsbury's: 146 departures seen
- Sutton / Marshall's Road: 145 departures seen
- How it is measured
- Every day, 05:00–23:59. On time means leaving no more than 2.5 minutes early or 5 minutes late. A day with less than four hours of data collected shows no daily figure. How these figures are made.
Gaps in the record for this period (39)
Most recent first. Hover a week on the chart and it will name the gap behind it. Most are a few missing hours on an otherwise ordinary day.
- 17 Sept 2026 partial day, no data 12:00-12:59: our collector was down (machine off or power cut)
- 28 Aug 2026 partial day, no data 20:00-23:59: our collector was down (machine off or power cut)
- 29 Jul – 26 Aug 2026 no collection: the volunteer BODS archive was down and our own collector had not yet started
- 28 Jul 2026 partial day, no data 11:00-23:59: no collection: the volunteer BODS archive was down and our own collector had not yet started
- 7 Jul 2026 partial day, no data 15:00-15:59: gap in the volunteer BODS archive (its collector was down)
- 5 Jul 2026 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
- 4 Jul 2026 partial day, no data 06:00-21:59: gap in the volunteer BODS archive (its collector was down)
- 2 Jul – 3 Jul 2026 gap in the volunteer BODS archive (its collector was down)
- 8 Jun 2026 partial day, no data 07:00-08:59: gap in the volunteer BODS archive (its collector was down)
- 7 Jun 2026 partial day, no data 12:00-12:59, 18:00-19:59: gap in the volunteer BODS archive (its collector was down)
- 6 Jun 2026 partial day, no data 12:00-12:59, 16:00-16:59, 18:00-18:59: gap in the volunteer BODS archive (its collector was down)
- 27 Apr 2026 partial day, no data 12:00-12:59: gap in the volunteer BODS archive (its collector was down)
- 21 Apr 2026 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
- 20 Apr 2026 partial day, no data 15:00-23:59: gap in the volunteer BODS archive (its collector was down)
- 16 Apr 2026 partial day, no data 12:00-15:59: gap in the volunteer BODS archive (its collector was down)
- 28 Feb 2026 partial day, no data 06:00-18:59: gap in the volunteer BODS archive (its collector was down)
- 16 Feb – 27 Feb 2026 gap in the volunteer BODS archive (its collector was down)
- 15 Feb 2026 partial day, no data 16:00-23:59: gap in the volunteer BODS archive (its collector was down)
- 30 Jan 2026 partial day, no data 20:00-23:59: gap in the volunteer BODS archive (its collector was down)
- 25 Dec 2025 no bus service on Christmas Day
- 23 Dec 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
- 5 Dec 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
- 24 Nov 2025 partial day, no data 17:00-17:59: gap in the volunteer BODS archive (its collector was down)
- 17 Nov 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
- 15 Nov – 16 Nov 2025 no London vehicles in the national feed — TfL's export to BODS was down (the volunteer archive itself was collecting)
- 14 Nov 2025 partial day, no data 06:00-07:59, 13:00-23:59: gap in the volunteer BODS archive (its collector was down)
- 31 Oct 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
- 17 Oct 2025 partial day, no data 06:00-07:59: gap in the volunteer BODS archive (its collector was down)
- 10 Oct 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
- 3 Oct 2025 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
- 19 Sept 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
- 5 Sept 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
- 1 Aug 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
- 18 Jul 2025 partial day, no data 06:00-09:59: gap in the volunteer BODS archive (its collector was down)
- 8 Jul 2025 partial day, no data 06:00-08:59: gap in the volunteer BODS archive (its collector was down)
- 6 Jul – 7 Jul 2025 gap in the volunteer BODS archive (its collector was down)
- 5 Jul 2025 partial day, no data 18:00-23:59: gap in the volunteer BODS archive (its collector was down)
- 4 Jul 2025 partial day, no data 06:00-14:59: gap in the volunteer BODS archive (its collector was down)
- 25 Jun 2025 partial day, no data 06:00-11:59: gap in the volunteer BODS archive (its collector was down)
For latest timetable and route information, see TfL's official page.
Contains public sector information licensed under the Open Government Licence v3.0; bus data via the DfT Bus Open Data Service and Transport for London. Figures are computed from observed bus positions, every day, 05:00–23:59. How these figures are made. Bus positions from the Department for Transport’s Bus Open Data Service (BODS); the Department for Transport cannot warrant the accuracy or quality of the data published there. Positions before September 2026 come from the Bus Open Data archive generously built and kept by Open Innovations, with thanks. Route lines and stops: Powered by TfL Open Data. Contains OS data © Crown copyright and database rights 2016. Geomni UK Map data © and database rights [2019]. These pages and the bus replay are built independently from open data: Transport for London, the Department for Transport and the bus operators had no part in making them, and none of them endorses them. Not for planning a journey.