The GScholar link had many studies, yes. I found some conflicting opinions.
Institute of Transportation Studies, UC California [0]:
“There is, however, no empirical study that demonstrates that the 85th percentile rule optimizes safety.”
Hilda Ofori-Addo, University of Louisiana [1]:
“85th percentile speeds of vehicles are greatly affected by roadway characteristics. Therefore, roadway characteristics should be considered as equally important…”
I’ll note that this also had the lowest rate of crashes when vehicle speeds were <= 1 MPH from the 85th percentile, but there was also a confusing (to me) multi-modal distribution after that, with a 7 MPH delta having strikingly higher rate than anything else. I suspect, as the author admits, this may be due to other factors such as area type, road traffic volume, etc.
The GScholar link had many studies, yes. I found some conflicting opinions.
Institute of Transportation Studies, UC California [0]:
“There is, however, no empirical study that demonstrates that the 85th percentile rule optimizes safety.”
Hilda Ofori-Addo, University of Louisiana [1]:
“85th percentile speeds of vehicles are greatly affected by roadway characteristics. Therefore, roadway characteristics should be considered as equally important…”
I’ll note that this also had the lowest rate of crashes when vehicle speeds were <= 1 MPH from the 85th percentile, but there was also a confusing (to me) multi-modal distribution after that, with a 7 MPH delta having strikingly higher rate than anything else. I suspect, as the author admits, this may be due to other factors such as area type, road traffic volume, etc.
[0]: https://escholarship.org/content/qt5hg5m6sm/qt5hg5m6sm.pdf
[1]: https://media.proquest.com/media/hms/PFT/2/gUjrJ?_s=mHpv4T4%...