  In traffic safety research, extracting information from crash narratives
using text analysis is a common practice. With recent advancements of large
language models (LLM), it would be useful to know how the popular LLM
interfaces perform in classifying or extracting information from crash
narratives. To explore this, our study has used the three most popular publicly
available LLM interfaces- ChatGPT, BARD and GPT4. This study investigated their
usefulness and boundaries in extracting information and answering queries
related to accidents from 100 crash narratives from Iowa and Kansas. During the
investigation, their capabilities and limitations were assessed and their
responses to the queries were compared. Five questions were asked related to
the narratives: 1) Who is at-fault? 2) What is the manner of collision? 3) Has
the crash occurred in a work-zone? 4) Did the crash involve pedestrians? and 5)
What are the sequence of harmful events in the crash? For questions 1 through
4, the overall similarity among the LLMs were 70%, 35%, 96% and 89%,
respectively. The similarities were higher while answering direct questions
requiring binary responses and significantly lower for complex questions. To
compare the responses to question 5, network diagram and centrality measures
were analyzed. The network diagram from the three LLMs were not always similar
although they sometimes have the same influencing events with high in-degree,
out-degree and betweenness centrality. This study suggests using multiple
models to extract viable information from narratives. Also, caution must be
practiced while using these interfaces to obtain crucial safety related
information.
