The Department for Transport allow the analysis of STATS19 data by many different geographies including Westminster Parliamentary Constituency. Although responsibility for road safety lies with local authorities, MPs and constituents often find it useful to understand what is happening at this level. Constituencies also offer a smaller area of analysis on certain large local authorities.
The Parliamentary Advisory Council for Transport Safety publishes a interactive map showing casualties by Westminster parliamentary constituency. As well as showing traditional analysis of casualty groups it also highlights the vehicles in conflict with casualties by type. The dashboard is updated annually about one month after the official DfT annual results are published.
Recently, the House of Commons Library published a PowerBI dashboard which offers more limited functionality.