Traffic Data Collection Day – A Conversation With Sam Milsom from Open Data Manchester  – Part 3

Welcome back for our 3rd and final instalment of A Conversation with Sam Milsom; one of our data gurus! In today’s blog, Sam will be walking us through the Traffic Data Collection day that took place in April. 

If you didn’t catch the previous blogs, make sure to check out part one and part two.

And before we jump into part three, here’s an overview of our team and what they’re getting stuck in with: 

Sam Milsom is one of the local people involved with Our Streets Chorlton. He also works at community interest company (CIC) Open Data Manchester. 

A data expert, one of his passions is communicating data in a simple, understandable way and enabling people who ‘don’t do data’ to enjoy it, access it, use it and be empowered by it.

As part of his work with the Chorlton Climate Action Partnership he, along with ODM colleagues Julian Tait and Sophie Walker, is supporting the three mini-projects with data collection and analysis. We’re also working with the community to develop a cohort of Data Champions who will be involved in collecting and understanding data about Chorlton.

They are here to help Our Streets Chorlton tell the story of current traffic levels and air quality in the neighbourhood, as well as measure any changes over the course of the project.

We’ve spoken to Sam about their work with the project to date and he’s written a series of bitesize blogs to share more about who they are, what they do and their work with Chorlton. Here’s part three –  Traffic Data Collection Day.


Roadside Traffic Counts, A Conversation with Sam Milsom

On Wednesday April 7 2021, we carried out our first roadside traffic survey, conducted by our initial cohort of data champions. The purpose of this was to pilot our methodology in advance of our first ‘official’ surveys which will be carried out in June for the school streets project at Barlow Hall Primary School.


Throughout March we recruited and trained our first cohort of Data Champions. As detailed in the last blog, we designed the training and the traffic surveys with the community. We were really pleased that we had a total of 24 people take part in these sessions. 

Pilot day

On Wednesday 7 April 2021 we carried out the pilot traffic count in order to give our volunteers a chance to practice, and to iron out any creases in our methodology. The count took place outside Barlow Hall Primary School on Darley Avenue, at the location of one of our calibrated air quality sensors.

In keeping with the Department of Transport’s own methodology, the count ran from 7am-7pm, breaking the day into 1-hour shifts. Each shift had two volunteers – each volunteer was responsible for counting traffic travelling in a single direction – and a third representative from Our Streets Chorlton to provide support and talk to the public as necessary (so the counters weren’t distracted!). A total of 20 volunteers took part alongside the project partners.



We were lucky that the weather remained dry, although it was a rather cold day, with temperatures in the morning below freezing! The traffic counting went without a hitch, and there was a general vibe of camaraderie amongst those working together.



We purposefully located the count beneath the location of our calibrated EarthSense Zephyr AQ sensor, so that we could begin to draw links between the traffic counts and the data from the sensor. That said, we were counting traffic not only during a lockdown, but also a school holiday and during a period of time when the nearby Barlow Moor Road was closed for roadworks. In short, the data we were collecting was never going to be representative.  

We did have one interesting observation with regards to air quality. At one point in the day, a car was observed idling and, taking note of the time, we were able to match it with a significant spike in poor air quality. Not only did this encourage us in the efficacy of our AQ sensor, but it means we would also expect to see the same thing during the peak hours and especially during the school run during drop off and pick ups – if cars are sat idling, of course. 

If you want to explore these results a little bit further you can do so here.

Get Involved

The feedback from the volunteers was overwhelmingly positive, with many commenting that it had been surprisingly fun and enjoyable. Luckily there are more opportunities for you to join in on the fun in the coming weeks. Our next steps are to carry out the first ‘official’ traffic counts, which will take place around the school streets project. Sustrans is due to carry this out with Barlow Hall Primary School on the 15th & 16th of June, and our Data Champions will be taking part in traffic counts the week before, the week after and then one month after. This will allow us to baseline before the project, measure any change in behaviours afterwards, and then assess whether any behaviour change has become embedded.

If you’re keen to get involved and become a Data Champion, we have two training sessions at the very start of June. The dates and Eventbrite links are below: 

If you’re already trained up and want to put your name down for a volunteer slot, just drop us a line or add your name into the google sheet rota !

And before you leave, here are the Traffic Data Collection days for your diaries:

  • Wednesday the 9th of June 
  • Wednesday the 23rd of June
  • Wednesday the 14th of July

See you soon!