While it's not aimed specifically at benzodiazepines, you can apply Tom McLellan's ASI (Addiction Severity Index) to BZD use. It might be a useful secondary measurement, although it is primarily aimed at individuals using BZDs illicitly, and might not be of much use for individuals taking legally prescribed BZDs. Are you simply trying to measure "dependence" (e.g. how dependent an individual is on BZDs from a psychoneurological standpoint) or are you looking at overall severity of a patient's benzodiazepine use disorder?
there was an effort at the Addiction Research Institute in Toronto to develop a scale for measuring benzodiazepine WITHDRAWAL similar to those they had used for alcohol (the CIWA-A) and opioids (CINA) and they called it the CIWA-D (diazepam). However, the signs and symptoms of benzodiazepine withdrawal proved to be so variable and inconstant (including appearing in very different orders at different times) that I understand they gave up on it and never published on it. Benzo withdrawal can look exactly like alcohol withdrawal, with a gradual increase in hyperautonomic signs and symptoms, followed by development of seizures, followed by delirium, or it can present with delirium and no autonomic signs, or can include depersonalization, dereealization and hypnogogic/hypnopompic hallucinations with insight and then progress to delirum, and the hyperautonomia can occur late in the syndrome.
We published a paper (link: https://www.researchgate.net/publication/278412275_Eight-week_Depression_Program_Decreases_Usage_of_Benzodiazepines) on benzodiazepines showing how people that participate on our depression and anxiety program decrease dramatically the amount of benzodiazepines. We used a custom made test called the Nedley depression and anxiety assessment test we published a paper on it here: https://www.researchgate.net/publication/278411982_Nedley_Depression_Hit_Hypothesis_Identifying_Depression_and_Its_Causes?ev=prf_pub in it it has some questions about benzodiazepine usage.
Article Eight-week Depression Program Decreases Usage of Benzodiazepines
Article Nedley Depression Hit Hypothesis: Identifying Depression and...