Estimation of capacities on Florida freeways.

Details

• Creators:
  Elefteriadou, Lily ; Kondyli, Alexandra ; St. George, Bryan
• Corporate Creators:
  University of Florida. Transportation Research Center
• Subject/TRT Terms:
  • Freeways
  • Highway capacity
  • Traffic estimation
  • Traffic flow
  • Oversaturation (Traffic flow)
  • Field studies
  • Urban highways
  • Rural highways
  • Multilane highways
  • Bottlenecks
• Publication/ Report Number:
  BDV32-977-03
• Resource Type:
  Tech Report
• Geographical Coverage:
  Florida
• Corporate Publisher:
  Florida Department of Transportation
• Abstract:
  Current capacity estimates within Florida’s travel time reliability tools rely on the Highway Capacity Manual (HCM 2010) to ; estimate capacity under various conditions. Field measurements show that the capacities of Florida freeways are noticeably ; lower than the values recommended in the HCM 2010, by an order of a few hundred vehicles. In addition, recent research has ; shown that maximum freeway throughput may differ between undersaturated and oversaturated conditions, and this is not ; acknowledged in the HCM 2010. ; The main objective of this research was to collect field data at several urban and rural freeway and multilane locations in Florida ; in order to measure capacity flows and to provide recommended capacity values before and after the initiation of oversaturation. ; The research team obtained data at urban and rural freeways and multilane highway segments across Florida. The urban ; freeway data were obtained through the Statewide Transportation Engineering Warehouse for Archived Regional Data ; (STEWARD) at various types of bottlenecks including merge junctions, weaving segments, as well as geometric bottlenecks ; (lane drops), while the rural freeway and multilane highway data were obtained from the permanent count stations of FDOT. ; Incidents and weather data were also obtained to ensure that the final datasets included capacity observations due to excess ; demand and not due to random events such as incidents or bad weather. ; Various capacity measures were investigated, and it is recommended to define pre-breakdown capacity as the 85th percentile of ; the 15-min average pre-breakdown flow and the post-breakdown capacity as the average discharge flow. A clear drop in ; throughput between pre-breakdown and discharge capacity values was observed. Recommendations on capacity values as a ; function of the number of lanes and the segment type for both urban and rural locations are offered. This research also proposes ; revised density thresholds for defining Level of Service on various types of segments consistent with the recommended capacity ; values.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28046/dot_28046_DS1.pdf
• File Type:
  [PDF - 2.73 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:8912a88be45ce6d98ac7cd3cd745ef52f0c858d399d8fd725d8417e26e0b629d236cefa008f4b90edd723c1930df2be3608ffa239c95e3193ad0d9f966d3296d