The BBC News website's road casualties map, which shows all recorded deaths on Britain's roads between 1999 and 2010, has been enormously popular.
As a result, we have received hundreds of emails asking a range of questions. Here are the answers to some of the most frequent about the map and related features.
Where does the data come from?
Why do you say the data covers Great Britain when it includes Northern Ireland?
A crash close to where I live is missing or the details are inaccurate. Why?
A crash I am familiar with is not located in the right place on the map. Why?
The map doesn't seem to show individual crashes for my postcode area. Is there a problem?
Some of the incidents I have looked at say it was snowing at the time, but it was summer. Is there a problem with the data?
Where did you get the 730,000 figure for all road casualties?
How did you calculate the £15 - £32bn economic cost?
What is the source of the Dangerous Driving slide?
What is the difference between a "serious" and "light" injury?
Are you more likely to be involved in a collision during rush hour in a city?
