In mid-April 2021, East Road in Cambridge was closed for 2 weeks. I didn't realise how important a small bit of road could be until I tried to use it recently - what should have been a simple drive instead took me completely around town due to all of the bus-only and one-way streets.

After this excusion, I decided to take a look at the impact of the closure on traffic more generally. This is made possible using data provided by Smart Cambridge.

Traffic levels are impacted by many things - day of week, school holidays, pandemic-related lockdowns. To fairly analyse the impact of the roadworks ideally all other factors should be constant so the general level of traffic is the same. That said, if things are different (which they absolutely will be) then that's just tough because it's the real world. Here, we're interested in the construction period Tuesday 6 April to Tuesday 20 April. This partially coincides with school holidays from 29 March to 9 April, Good Friday on 2 April, Easter Monday on 5 April,¹ and lockdown restrictions easing on 12 April. Newmarket Road was also closed from 26 Mar - 2 Apr, and there were a total of 73 work-related road changes from 1 - 15 April. sigh

There are two almost-comparable windows here: Tuesday 30 - Thursday 1 and Tuesday 6 - Thursday 8. They're both in the school holidays, but before the long bank holiday weekend.² That's what's selected by default in the table below,³ but you can use the buttons to change which date ranges are compared.

The map shows the change in average traffic speed between the base and comparison time periods. You can click the lines to see more detail, and most roads have data for each direction separately (traffic drives on the left). Some are missing due to lack of data. Unfortunately traffic volume also isn't available, so we can't do any fun comparisons with that.