Canyon Highway District #4 (CHD4) has developed a Draft Transportation Planning Study that will prioritize projects for the future. More information regarding the Highway District's function and Asset Management Program is provided below.


Demographic trends were evaluated based on Community Planning Association of Southwest Idaho (COMPASS) models and supporting Geographic Information System (GIS) data. The following exhibits identify current conditions, historical trends, and future projections of demographics within the CHD4 jurisdiction.


Multimodal Transportation

Multimodal transportation planning documents from other jurisdictions were evaluated along with stakeholder and CHD4 personnel meetings for inclusion into the report. The exhibits are based on GIS data provided by COMPASS. The following are definitions of terms used in the report:

  • Pathways are considered to accommodate multi-modal transportation and are physically separated from the roadway. Pathways are typically used in areas where vehicle traffic travels at high speeds.
  • Bike Lanes are lanes approximately 4-5 feet in width dedicated to modes of transportation faster than walking/running and slower than vehicles.
  • Shared Roadways are roadways dedicated to modes of transportation faster than walking/running. Automobiles are anticipated to be able to pass bicyclists with an acceptable amount of delay for traffic to create a passing opportunity.
  • Sidewalks are dedicated to walking/running transportation.

Please note, bus stops are also displayed.


Roadway Operations

The CHD4 roadway network was analyzed by intersections and road segments. Traffic volumes counted for 2018 and projected for 2040 were used to determine the Level of Service. A LOS D is adequate but approaching unstable flow. Therefore, LOS D segments and intersections were identified, and LOS E or F segments and intersections were listed as needing improvement.



Two safety analysis approaches for road networks are analyzing crash data, referred to as substantive, and comparison of actual conditions to recommended standards or practices, referred to a nominal approach.  Evaluation of crash data can look at trends across the whole roadway system or identify specific locations of concern.

An example of a system wide concern might be a higher than anticipated nighttime intersection crash rate that may indicate a need for enhanced nighttime visibility.  A specific location issue might be a curve that has a higher crash rate than the remainder of the road segment.  Intersection and non-intersection related crashes are often analyzed separately, since these crash types typically have different contributing factors and therefore involve different mitigation measures.

Systematic (system wide) issues are often identified by looking for trends in crash data, including time of day, weather, or contributing circumstances. Specific locations of concern are typically identified by looking for clusters of crashes along a road segment or intersection, and then analyzing data for that location.  The nominal approach compares the system to geometric standards or guidelines that may or may not have an effect on crash occurrences.  Examples of these are road curvature, intersection angle, road grade (steepness), and side slopes.

Asset Management 

One of the primary obligations of the Highway District is to maintain the roads, bridges, culverts, and related components of the local road system.  There are 320.1 miles of roadway in the District’s current road network, which the District evaluates the condition of every two years.  Based on condition, history, traffic, and coordination with other needs, the District develops a schedule for preventative maintenance and major rehabilitation with the goal of maintaining an acceptable level of pavement condition throughout the road network.  There are 109 bridges maintained by the District as part of the roadway system that vary from 8’ to 433’ in length.  Bridges are inspected on a 1, 2, or 4 year cycle depending on their condition.  Based on the condition ratings of various bridge components, maintenance, rehabilitation/repairs, replacements are scheduled.  Bridge width is also considered to determine the need for widening.  The District’s inventory of all culverts, including those at driveways, exceeds 4100, with 139 that have diameters or spans greater than 42 inches.  Similar to bridges, culverts larger than 30” (225 total) are inspected every 1 to 4 years depending on condition and are scheduled for maintenance, rehabilitation, or replacement depending on their condition.  Pavement, bridge, and culvert projects are coordinated to provide the most efficient approach to maintaining these public assets.  A more detailed description of these programs is provided in the Asset Management Summary.