Are drivers and cyclists just as dangerous to pedestrians?

Cyclists are just as dangerous to pedestrians as drivers. That’s the claim made by an article on The Times website today.

According to transport correspondent Phillip Pank, analysis of the 2012 road accident figures published by the Department for Transport reveals: “When serious injuries are measured as a proportion of distance travelled, cyclists injured 21 pedestrians per billion km travelled in 2012 compared with 24 pedestrians injured by drivers.”

To steal a phrase from debunker of Bad Science Ben Goldacre, we think you’ll find it’s more complicated than that.

What you really want to know here is how much of a risk different road users pose to pedestrians. It could be therefore misleading to take as your starting point the distances travelled by the those road users. You want the distances travelled by pedestrians.

road.cc doesn’t have an in-house statistician (applications are open, but be warned: the pay is lousy), so no doubt there are serious flaws in what follows and we expect smarter people than us to point them out in the comments.

The national travel survey says the average person travelled 6,691 miles in 2012. There 60 million people in the UK, so that's just over 400 billion miles.

Of that distance, 3 percent is walked so that's 12 billion miles of walking. For the sake of argument, let’s say that half of that is in the kind of urban environments The Times is talking about.

That’s 6 billion miles of walking which would get you out to Pluto’s orbit, if the frigid outer reaches of the solar system are your thing.

There were 79 pedestrians killed or seriously injured (KSI) by bikes in urban areas in 2012, so that’s one KSI per 75 million miles walked.

By contrast, there were 4,679 pedestrian KSIs involving motor vehicles - one KSI per 1.25 million miles walked.

That means for every mile you walk, you are 60 times more likely to be killed or seriously injured by a driver than a cyclist.

Another criticism of The Times’ analysis, and one that the paper touches on, is that the injuries sustained by pedestrians who are hit by cyclists are likely to be less severe than injuries to those who are hit by drivers.

The DfT’s classification of serious injury is:

Serious injury: An injury for which a person is detained in hospital as an “in-patient”, or any of the following injuries whether or not they are detained in hospital: fractures, concussion, internal injuries, crushings, burns (excluding friction burns), severe cuts, severe general shock requiring medical treatment and injuries causing death 30 or more days after the accident.

An injured casualty is recorded as seriously or slightly injured by the police on the basis of information available within a short time of the accident. This generally will not reflect the results of a medical examination, but may be influenced according to whether the casualty is hospitalised or not. Hospitalisation procedures will vary regionally.

So a broken collarbone or mild concussion comes under the same heading as multiple broken bones and severe brain damage.

On the basis of its pedestrian-injuries-per-billion-vehicle-miles analysis, The Times concedes that “drivers are five times more likely than cyclists to kill a pedestrian.” It doesn’t seem unreasonable to expect that they are also far more likely to inflict the most severe injuries.

After all, what would you rather be hit by, a Mondeo doing 30mph, or a skinny cyclist doing 20mph?