The Safe Passing Distance index (SPDi)

Just scroll through your Strava feed and it won't be long before you find someone bemoaning yet another 'close pass'. Get out on the road and it's not funny how distinct patterns of behaviour emerge among drivers of certain soon-to-be-shamed vehicles. Ever been innocently idling along a country lane when – woah, what the? yet another black BMW X5 (second gen model) just screamed past! Really? Again?! Every. Fricking. Time.

Years ago, just days after learning to drive, I took a wrong turn and nosed into a one-way street. A particularly obnoxious Addison Lee (London-centric private hire company) driver accelerated up the road so we were plate-to-plate, slammed his brakes on and bawled me out. I've lost count of the number of examples of poor, aggressive or illegal Addison Lee driving I've witnessed since.

The point is: there's more than a hint of confirmation bias at play here, which is why we decided to conduct our own pseudo-scientific study to establish the facts, Benitez-style, once and for all. Fact.

The sciencey bit

Over the last four days and five-and-a-half rides (does Zwift count?), we've worked tirelessly to reinforce and accurately document our prejudices. Average car values have been rigorously guessed at and average passing distances comprehensively approximated. Now, for the first time, the wholly controvertible truth is revealed.

Yes, an unmistakeable bell-curve. Our spurious analysis reveals a strong positive correlation between vehicle owners with some deep-seated sense of inadequacy and the tendency to close-pass cyclists at speed. To the lower left, a distinct cluster of souped-up, second-hand hot hatches and white vans of various sizes. Over on the bottom right, a smattering of ill-deserved privilege and vulgar ostentation (do the super-rich have minions take their driving tests for them?).

We came to a stark and damning conclusion: a lot of cars of all makes and models still pass really close to cyclists when overtaking - and that's bloody dangerous.

The letter of the law

Rule 163 of the UK Highway Code stipulates that drivers of cars and other vehicles should give cyclists - and motorcyclists and horse riders for that matter - at least as much room as they would when overtaking a car. The use of the word "should" rather than "must" indicates this is advisory only and not a legal requirement. To secure a conviction, you'd need to prove beyond reasonable doubt a driver was guilty of careless or dangerous driving under the 1988 Road Traffic Act. And frankly that's just not going to happen without video evidence.

Guidance of 1.5 metres is frequently given, but who's got a tape measure or yardstick handy out on the road? Worry not, if you can reach out with your right hand and scratch a key down the side of a car as it overtakes, they're probably passing too close (best not try this).

Get involved

Cycling UK has its Too Close for Comfort initiative and the London Cycling Campaign has a Stay Wider of the Rider website (why not join forces, folks?) where you can sign a petition and put a pin on a map indicating details of a close pass.

If you think we've misplaced one of the cars within the Safe Passing Distance index, or have a suggestion for a make and model that we've missed, add a comment below. Ride safe. Drive safe. Stay safe.