Michigan urban trunkline intersections safety performance functions (SPFs) development and support.

Details

• Creators:
  Savolainen, Peter T. ; Gates, Timothy ; Lord, Dominique ; Geedipally, Srinivas ; Rista, Emira ; Barrette, Timothy ; Russo, Brendan J. ; Hamzeie, Raha
• Corporate Creators:
  Wayne State University ; Iowa State University. Institute for Transportation
• Subject/TRT Terms:
  • Signalized intersections
  • Unsignalized intersections
  • Highway safety
  • Traffic crashes
  • Urban highways
  • Crash data
  • Crash severity
  • Data analysis
• Publication/ Report Number:
  RC-1628
• Resource Type:
  Tech Report
• Geographical Coverage:
  Michigan
• Corporate Publisher:
  Michigan. Dept. of Transportation. Office of Research Administration
• Abstract:
  This study involves the development of safety performance functions (SPFs) for signalized and stop-controlled intersections ; located along urban and suburban arterials in the state of Michigan. Extensive databases were developed that resulted in the ; integration of traffic crash information, traffic volumes, and roadway geometry information. After these data were assembled, an ; exploratory analysis of the data was conducted to identify general crash trends. This included assessment of the base models ; provided in the Highway Safety Manual (HSM), as well as a calibration exercise, which demonstrated significant variability in ; terms of the goodness-of-fit of the HSM models across various site types. Michigan-specific SPFs were estimated, including ; simple models that consider only annual average daily traffic (AADT). More detailed models were also developed, which ; considered additional geometric factors, such as posted speed limits, number of lanes, and the presence of medians, intersection ; lighting, and right-turn-on-red prohibition. Crash modification factors (CMFs) were also estimated, which can be used to adjust ; the SPFs to account for differences related to these factors. Separate SPFs were estimated for intersections of only two-way ; streets and for those where at least one of the intersecting streets was one-way as the factors affecting traffic safety were found to ; vary between these site types. Severity distribution functions (SDFs) were also estimated, which can be used to predict the ; proportion of injury crashes which result in different injury severity levels. The SDFs may include various geometric, operation, ; and traffic variables that will allow the estimated proportion to be specific to an individual intersection. Ultimately, the results of ; this study provide MDOT with a number of methodological tools that will allow for proactive safety planning activities, ; including network screening and identification of high-risk sites. These tools have been calibrated such that they can be applied ; at either the statewide level or within any of MDOT’s seven geographic regions, providing additional flexibility to accommodate ; unique differences across the state. The report also documents procedures for maintaining and calibrating these SPFs over time, ; allowing for consideration of general trends that are not directly reflected by the predictor variables.
  More +
• Format:
  PDF
• Funding:
  2013-0070-4
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29195/dot_29195_DS1.pdf
• File Type:
  [PDF - 3.10 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:73638602280ce4f807b62668ba6a4f284392094cc207f06179781b7b09b0c3d223b5d25f3a55374a45676646e5d588e11d3f0a794976b28395d0b520edcacdc6