Monday, 19 November 2012

Why have scotland's roads got more lethal for pedestrians?

The scottish road statistics are out, and behind the "roads are getting safer" claims both walking and cycling has got more dangerous, as magnatom shows. This increase in ped/cyclist deaths is merely hidden by a drop in car deaths (gradual retirement of non-airbag, non-ABS fleet?)

The increase in pedestrian KSI is something to draw out.

If it was just an increasing in cyclist KSI, one could discount it by saying "due to an increase in inexperienced cyclists". One could also blame bikes that are more dangerous (fixed wheel) than -the official S Gloucs recommend cycle path bike, an MTB with disk brakes and enough front travel to handle potholes and 20cm drops in the paths.

You can't do so much victim blaming the pedestrians. Unless there has been a surge in walking, something else is happening.

Here are some possibilites and ways to test them.

Hypothesis

Test
More pedestrians -cost of fuel and public transport
any gathered pedestrian counts.
Urban walking has somehow got more dangerous
Increase in percentage KSI in urban/rural environment, assuming constant pedestrian count

increase in speed after cameras removed

turn cameras on but don't issue tickets -just #of vehicles
speeding in town/country roads

drivers on phone

look at phone records after KSI; survey percentage of drivers phoning or texting in urban & rural environments.

drivers texting

consult phone records (and phone)

pedestrians on phone or texting

again: phone records & sampling of pedestrian numbers.

bad weather

compare KSI stats on wet days vs dry days at same time of year/day of week.
Risk compensation of newer cars
Compare change by car model/year from previous year of KSI statistics.

All these are testable -if not in 2011, from now. Cameras can measure the #of speeding cars in an area, correlated with KSI to show if it is an increase in speed, or some other factor.


There's another hypothesis: increase in driving kilometres, but that's already decreasing. Maybe a reduction in car traffic increases speed by reducing congestion.

The two recent trends are: better cars possibly triggering risk compensation, and a growth in phone and texting use.

Phone and text use can be gathered after any RTC -the police can sieze the phone and look for half-competed texts in the drafts folder; phone records will show texts sent and received, phone calls (recent and active). The mobile phone companies will also have records of web requests  and emails made at the time of any crash, though not the content of encrypted communications (mail could be background updates, as facebook and twitter activity could be).


Without attempts to collect these statistics, the reasons for the 6% increase in KSI numbers cannot be determined -and hence cannot be fixed.

There is no evidence that Transport for Scotland are doing this -and until then the causes are guesswork.

If the Pedal on Parliament people want to push for something in the statistics gathering, this is what they should be thinking of -especially the gathering of phone/text data from both drivers and pedestrians.

(side note: cyclist texting/phoning is much rarer than driving; the increase there is unlikely to be due to a rise in cyclists using phones. The other hypothesis list may apply to the increase there -or there may be other causes).

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