# How wide are London's pavements? Measuring 7,908 cross-sections in Whitechapel

No UK dataset records pavement width. I measured left pavement, road and right pavement for 10 Whitechapel streets, then tried four ways to prove myself wrong.

Published: 2026-11-05

No public dataset tells you how wide a pavement is in the UK: not the left side, not the right side, and not the carriageway in between. So I measured all three on the same cross-section for 10 streets in Whitechapel, East London, and ended up with **7,908 cross-sections**. Measuring was the easy part. The work was deciding which numbers to trust.

## Why does pavement width matter?

Width decides whether a wheelchair, a pushchair or two people walking side by side can get down a street. UK government guidance (*Inclusive Mobility*, Department for Transport) recommends 2 metres of clear footway and treats **1.5 metres as the minimum acceptable** where space is constrained. Councils and planners make decisions against those numbers every day, usually without a measured baseline for the street in front of them.

I picked Whitechapel because the UK's geospatial data for it is publicly available and the streets are a good stress test: old, narrow, irregular, full of junctions.

## What is wrong with the obvious method?

The obvious method fires a line straight out from the road centreline and measures the pavement it crosses. On a straight street that works.

At a junction it fails badly. The line shoots down the side street and counts the whole side street as pavement. My first run told me one pavement was **44 metres wide**.

The bigger problem is that this method is right about **95% of the time**. The failures don't move the average, so summary statistics look fine. They hide in the tail, **4.7% of readings**, and the tail is where the bad decisions get made: those are the junctions and pinch points that matter most for accessibility.

## How did I fix the measurement?

I changed the question each measurement asks:

* **Aim at the kerb, not the middle of the road.** Each cross-section is anchored to the kerb line, so a junction ends the measurement instead of extending it.
* **Measure from surveyed Ordnance Survey geometry.** Aerial imagery is used only to check a number, never to set one.
* **Let OpenStreetMap fix what OS mislabels.** Cycle tracks filed as "path" would otherwise be counted as pavement.
* **Reject anything it can't trust, and record why.** Every discarded cross-section carries a reason code. Nothing disappears silently.

## How do you know the numbers are right?

I tried to prove myself wrong four ways that share no code with the measurement:

1. **Against Ordnance Survey's own carriageway widths:** median difference **0.19 m**, correlation **r = 0.91**.
2. **Against the surveyed surface:** the median measured pavement strip sits **99.9%** on surveyed pavement polygons.
3. **Closure against building frontage:** where buildings line both sides, left + road + right should add up to the frontage-to-frontage distance. The median gap is **0.00 m**.
4. **Sensitivity:** 12 different parameter settings move the answer by **under 10 cm**.

None of these proves the data perfect. Together they make it very hard for a systematic error to hide.

## What did the data show?

**58% of Gunthorpe Street's pavement is narrower than 1.5 m**, below what UK guidance calls the minimum acceptable. Along **41% of one side there is no pavement at all**.

That is the kind of finding an average would never surface, and the kind a council can act on.

## What I took away from it

* **Validate the tail, not the mean.** A method that is right 95% of the time can still be useless for the decisions that matter.
* **Separate the instrument from the check.** Imagery that sets numbers can't also be the thing that validates them.
* **Make rejection a first-class output.** "We couldn't measure this, and here's why" is data too.

I'm planning to publish the cross-sections and strip maps for all 10 streets. If you work on streets, accessibility or urban data and want them sooner, [get in touch](https://aliahmed.si/contact/).

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Written by Ali Ahmed · [Original article](https://aliahmed.si/blog/whitechapel-pavement-widths/)