% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/data.R
\docType{data}
\name{london_tree}
\alias{london_tree}
\title{London Road Collisions - Hierarchy}
\format{
A data.frame with 81 rows and 2 columns:
\describe{
  \item{node_id}{Character identifier of each node.}
  \item{parent_id}{Character identifier of the parent node. \code{NA}
    for the root.}
}
}
\source{
Constructed from the leaf-level codes in \code{\link{london_collisions}}.
See \code{data-raw/} in the GitHub repository for the build script.
}
\usage{
london_tree
}
\description{
Hierarchical classification of road collisions by light conditions,
road type, and junction detail.
}
\details{
3-level tree: Root -> Light conditions (Daylight/Darkness) -> Road type
(5 types) -> Junction detail (7 types). 68 leaf categories.
}
\examples{
data(london_tree)
head(london_tree)
}
\seealso{
\code{\link{london_collisions}}
}
\keyword{datasets}
