I have produced an interactive web map showing pedestrian and cyclist casualties in non-built-up areas of England and Wales 1999-2008, based on STATS19 data that I analysed for my masters dissertation.
Separate layers are provided for pedestrians and cyclists for three injury severities. It includes a postcode search, casualties are clustered at lower resolutions, and the size of the casualty marker increases for higher zoom levels. The map is created using the Ordnance Survey OpenSpace JavaScript library. The data is a little old now, but this was an interesting exercise in developing a map application: