If you live, walk or cycle on minor roads you probably think they've got busier over the years with more rat running. The DfT 2019 traffic data backed up what we’d seen and felt. It seems to correlate with the start of GoogleMaps navigation around 2009.

Satnav users won't be surprised - they ignore signposted routes that planners want you to take, and send you down minor roads all the time. Delivery drivers, taxis, minicabs more than half of private drivers were using satnavs by 2015 (DfT) and 78% by 2017 (uSwitch survey)

But some have questioned the data - not that minor road traffic is now higher - but that the benchmarking correction http://bit.ly/dft_benchmarking was wrong and growth has been over a longer period - to around 2000 - which, they say, would would mean it didn’t correlate with satnav use

But the first satnavs launched in 2000 and a third of drivers were already using them by 2009 (though you can see how google/waze then took the market). Early models were even worse at directing down minor roads as they assumed max speed on all roads and minor were also 30mph.

And this increase in traffic also correlates to an increase in road danger in minor roads. https://twitter.com/jackmaizels/status/1338462371858292741

You’re the maths genius. You work out if number of courier deliveries each day is material. Because my estimates make it sub 50 vehicle movements per day at absolute worst. And of those substitute multiple individual car trips. And unblock me if you’re going to spam me. Berk.

In fact I had a go. Feel free to challenge my estimates. Now added together all these deliveries *might* make a measurable difference to the main roads they drive to and from the depot on. But that’s not where traffic has been growing. https://twitter.com/simonstill/status/1338877877354369026

@PaulLomax wouldn't understand how rat run traffic had increased over the last decades because he lives on a street that would never have been a rat run. I know this because he DCMA'd my repost of one one his spreadsheets which sent me his home address. (!)

As self owns go this one was pretty sweet. (I’ve retyped the key numbers from his “copyright” spreadsheet and credited his work appropriately)