The combination truck planning time index is the ratio of the 95ᵗʰ percentile combination truck travel time to the combination truck travel time at reference speed, defined as the 85ᵗʰ percentile speed during weekday off-peak hours (9:00 a.m. to 4:00 p.m. and 7:00 p.m. to 10:00 p.m.). This measure represents the total travel time that a combination truck driver should budget to ensure on-time arrival at least 95% of the time.

• Annual Average Daily Traffic (AADT): The total vehicle volume on a roadway segment over 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: Vehicles classified as Classes 8-13 by Federal Highway Administration; commonly referred to as a “semi-truck.”
• Combination Truck Factor: The proportion of heavy vehicles that are combination trucks (FHWA Vehicle Classes 8-13) to all vehicles.
• Combination Truck Planning Time Index: Total travel time that a combination truck driver should budget to ensure on-time arrival to their destination at least 95% of the time. It is expressed as the ratio of the 95^th percentile combination truck travel time to the reference speed travel time.
• 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 the methodology report.
• Facility Type
  • Arterials: Signalized roadways that primarily serve through traffic, with intersections spaced two miles or less apart.
  • Highways: High-speed roadways with signalized intersections spaced more than two miles apart.
  • Freeways: Multilane, divided highways 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. Multiple highway systems exist in Florida, with the following three maintained by the State of Florida with a little distinction:
  • National Highway System (NHS): Roads designated by Congress as nationally important for inter-regional travel, including roads designated as connectors to NHS intermodal facilities, which are part of the State Highway System, and other NHS 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) - A statewide network of high-priority transportation facilities, including the state's largest and most significant airports, spaceports, deepwater seaports, freight rail terminals, passenger rail and intercity bus terminals, rail corridors, waterways, and highways. The FDOT Source Book reports roadway SIS facilities on the SHS or the NHS.
• 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. The majority of travel typically occurs during the PM peak hour resulting in more congestion in the PM peak than in the AM peak.
  • 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.