Combination Truck Planning Time Index

Combination truck travel times vary from day to day, and drivers tend to recall the frustration of unexpected delays. Travel time reliability measures the extent of this unexpected delay. Planning Time Index (PTI) represents the additional time that a traveler should budget to ensure on-time arrival to their destination at least 95% of the time. The higher the PTI, the less reliable the travel time and necessitates additional time to ensure on-time arrival.

Methodology

Methodology: Combination Truck Planning Time Index

Combination Truck Planning Time Index (PTI) is the ratio of the 95ᵗʰ percent travel time to the travel time at reference speed. Reference Speed is the 85ᵗʰ percentile speed during weekday off-peak hours (9 am to 4 pm and 7 pm to 10 pm).

Calculation

`"Combination Truck Planning Time Index" = "Travel Time"_("95th percentile")/"Travel Time"_("reference speed")`

Reporting Periods

  • Peak Hour
  • Peak Period
  • Daily
  • Yearly
Definitions

Definitions: Combination Truck Planning Time Index

  • Annual Average Daily Traffic (AADT): The total volume of traffic on a highway segment for one year, divided by the number of days in the year.
  • Area Type
    • Urbanized Area: An area with a population of at least 50,000 people.
    • Non-Urbanized Area: An area with a population less than 50,000 people.
  • Combination Trucks: Trucks with vehicle classification from 8 to 13.
  • Combination Truck Factor: Represents the proportion of heavy vehicles that are combination trucks (Classes 8-13).
  • Context Classification: A classification assigned to a roadway that broadly identifies the various built environments in Florida, based on existing or future land use characteristics, development patterns, and the roadway connectivity of an area. For more information about context class, please reference methodology document.
  • Facility Type
    • Arterials: Signalized roadways that primarily serve through traffic with average signalized intersection spacing of two miles or less.
    • Highways: High speed roadways with signal spacing greater than two miles per signal.
    • Freeway: A multilane, divided highway with at least two lanes for exclusive use of traffic in each direction and full control of ingress and egress.
  • Highway System: An integrated network of roads and highways for motor and non-motor transport. Each highway system has roadways that are exclusive to their respective system.
    • National Highway System (NHS) - Roads designated by Congress as nationally important for inter-regional travel, including roads designated as connectors to NHS intermodal facilities.
    • State Highway System (SHS) - Roads under the jurisdiction of the State of Florida, and maintained by the Florida Department of Transportation or a regional transportation commission; includes roads with Interstate, US, and SR numbers.
    • Strategic Intermodal System (SIS) - Transportation system created by the Florida Legislature in 2003 to include statewide and regionally significant facilities and services, containing all forms of transportation for moving both people and goods, including linkages that provide for smooth and efficient transfers between modes and major facilities.
  • Planning Time Index (PTI): The ratio of the 95ᵗʰ percent travel time to the travel time at reference speed.
  • Reference Speed: 85ᵗʰ percentile speed during weekday off-peak hours (9 am to 4 pm and 7 pm to 10 pm).
  • Reporting Periods
    • Peak Hour: 5:00 p.m. to 6:00 p.m. on a weekday. This hour is chosen to allow consistent comparisons among transportation modes. It may not be the hour of greatest travel for any given roadway, mode or area.
    • Peak Period: 4:00 p.m. to 6:00 p.m. on a weekday in which travel is greatest. These peak period hours are chosen based on the hours of greatest travel in different area types.
    • Daily: For the average 24-hour day.
  • Segment: A portion of roadway defined by two boundary points.

Download Data

Date of last refresh: 01/19/2024

SOURCES

FDOT - Traffic Characteristics Inventory
FDOT - Roadway Characteristics Inventory Feature 147 (Strategic Intermodal System)
HERE Technologies - Travel Time Data