I think that Paul does have something here, but ideally needs to get the correct base figures - somehow I doubt that average minutes on stairs is something that is recorded anywhere. I would say that Paul's 10 minutes per day is generous across the entire population - a significant proportion of the public probably don't use them much at all (East Anglia bungalow owners?), while 20 minutes per day for anybody is a lot.
Most people however are involved with the road network at some point each day if they leave their house - especially as we should include pedestrian road usage in the road accident data (including pavements, as many of the recorded road deaths are on the pavements). 60 minutes would appear to be very generous as it is probably close to the average time vehicle users spend on the road. Paul's proposed values are in fact a very conservative estimate, and the true values would slew the results even more in favour of roads being much safer than stairs - possibly to as much as stairs being 8 times more dangerous than road use.
It is also likely that a similar ratio would be achieved if you include serious injuries, because just like on the roads, the vast majority of slips on the stairs do not result in death.
Stop press - I did a google, and guess what? The Americans do produce these sorts of statistics! Including the per year and lifetime odds of dying from a wide variety of causes.
http://www.nsc.org/lrs/statinfo/odds.htm
From their data (obviously US figures and accident rates), the chances of dying from these particular causes are:
Motor-Vehicle Accidents (all sources combined) - Deaths: 44,757 One Year Odds: 6,498 Lifetime Odds: 84
Fall on and from stairs and steps - Deaths: 1,588, One Year Odds: 183,155, Lifetimes Odds: 2,360
So at first glance we are completely wrong - motor vehicle accidents are 28 times more likely to kill you. But that is the US, where land is in general cheap, and they are lazy, so less stairs and more lifts, and a lot less pedestrian time, but proportionally much more road time (they think nothing of driving an hour each way to a restaurant in the evening). But replace the death figures with the UK equivalents and assume that the US usage profiles are accurate:
As we are talking odds here (i.e. 1/6498 probability of dying on roads in a single year), the maths is twisted a bit:
Roads 1/((3,200 / 44757) * (1 / 6498 )) = 90,885
Stairs 1/((1000 / 1588) * (1 / 183155)) = 290,850
So at a slightly closer second glance we are still miles out (3.2 times) from having a valid argument - unless you want to follow DfT standards of statistics that is.
However, I am not convinced that the US base translates well across to the UK situation, so the only conclusion I have is that the above numbers mean nothing at all, except that UK stairs are much more dangerous than US stairs per head of population.
I have also found the published data from the Home Acident Statistics collected from A&E admissions which used to be a very basic report, but has since been collected into a datawarehouse, and can be queried online or via the reports. Most importantly they do not appear to include death data, just accident incidents (broken down by cause to the Nth degree - 226 accidents involving a lollypop stick!). If anybody feels like wading through it please feel free, I don't have the time:
The lastest published data is
http://www.hassandlass.org.uk/query/reports/2002data.pdf, and the online query (which is very poorly designed) is at
http://www.hassandlass.org.uk/query/intro2.htm
The very high level summary is:
Home Safety Facts and Figures
More accidents happen at home than anywhere else.
Every year there are approximately 4000 deaths as the result of a home accident. Around 120 of these are below 15 years and 1300 over 75.
During 2002 there were 2.7 million home accidents requiring hospital treatment, of which 477,500 involved children under five.
Children under the age of 5 and people over 65 (particularly those over 75) are most likely to have an accident at home.
Falls are the most common accidents, which can cause serious injury at any time of life. 55% of accidental injuries in the home involve falls.
More women than men over the age of 65 die as the result of an accident in the home.
Approximately 1500 people aged over 75 die annually as the result of a fall.
Every year around 120 children under 14 die as the result of an accident in the home.
Around 25,000 under 5s attend Accident and Emergency Departments each year after being accidentally poisoned.
26,000 under 5s are burnt or scalded in the home every year. A hot drink can still scald a small child up to 15 minutes after it is made.
More accidents happen in the lounge/living room than anywhere else in the home.
Every year over 4,200 children are involved in falls on the stairs and 4,000 children under the age of 15 are injured falling from windows.
Boys have more accidents than girls.
The cost to society of UK home accident injuries has been estimated at £25,000 million annually.
The road data is obviously in a totally different format, and I am sure that Paul has better data anyway.