Published
Island Park roads are wider on purpose, and the reason is snow.
The county's road widths have a north-county exception written into them
Fremont County publishes recommended right-of-way widths for each class of road. Most of the table is what you would expect. What is not expected is the sentence immediately underneath it, which singles out this end of the county by name.
“The recommended width of the public roadway right-of-way for each classification is as shown in Table 1. Additional right-of-way width may be required in the north County (Ashton and Island Park) area to allow for storage of plowed snow.”
— Fremont County Development Code, 2011 Edition (Ordinance 2011-04), Appendix B, section 1.08.010. Consolidated through Ordinance 2026-03. Retrieved 1 September 2026
Snow has to go somewhere, and the code treats the place it goes as part of the road. That is the single most useful idea in Appendix B for anyone laying out ground up here: the right-of-way is not sized for the traffic alone, it is sized for the traffic plus the winter.
Table 1, with the values matched to the right rows
The table is short. One word of caution before reading it: in the county's PDF the column header runs to two lines, which makes the numbers appear to sit one row lower than the classes they belong to. The pairing below is the corrected one.
| Type of roadway | Minimum width of public right-of-way |
|---|---|
| Principal Arterials | 120 feet |
| Minor Arterials | 80 – 100 feet |
| Collectors | 70 – 90 feet |
| Local Roads | 60 – 80 feet |
| Subdivision Roads | 50 – 70 feet |
Notice that every class except the largest is a range rather than a single figure. That is deliberate, and the footnote explains what pushes a road toward the top of its range.
The footnote is where the real conditions are
Underneath the table the code lists what may require additional width, and it is a list of exactly the things that describe ground in this part of the county.
- Higher traffic corridors.
- Accommodation of extreme cut or fill sections.
- Steep slopes.
- Snow storage.
- Other site-specific considerations, which is the clause that lets Public Works take account of anything particular to one stretch of road.
Then two specific provisions that are more useful than the ranges themselves:
Fences should be constructed at least five feet beyond the toe of slope to prevent damage to the fence from plowed snow. That is a concrete, checkable number, and it is the answer to a question every landowner on a plowed road eventually asks after losing a fence line. The measurement is from the toe of slope rather than from the property line or the pavement edge.
And the bottom of the range is conditional: only low volume roads carrying fewer than 150 vehicles per day, with no future potential of higher volume, may be eligible for the minimum 50-foot right-of-way width. The narrowest option is not simply available on request. It requires both a current volume below the threshold and an absence of future potential, which is a judgement about what the ground might become rather than only about what it is now.
Put together, the width a given road actually needs is a function of several independent factors rather than of its class alone:
- The functional classification, which sets the range.
- Expected traffic volume, which moves the road within that range.
- Whether the alignment requires extreme cut or fill sections.
- The steepness of the ground it crosses, which the footnote names separately from cut and fill.
- How much plowed snow will have to be stored, where it will be thrown, and whether there is anywhere for it to go that is not somebody's fence line or ditch.
- Any site-specific consideration Public Works identifies for that particular road, since the ranges are recommendations rather than entitlements and a specific site can move within or beyond them.
How roads get classified in the first place
The classification is not the county's own invention. All roadways within Fremont County are classified in accordance with the appropriate Federal Highway Administration legislation, and all streets and highways are functionally classified as arterials, collectors, or local roads.
Where to actually look it up matters, and the code names three places:
- A description of the functional classification categories is in the Fremont County Transportation Plan.
- The plan also carries a Functional Classification System Map showing which roads carry which classifications.
- A map showing the functional classifications can also be obtained from the Idaho Transportation Department.
That last one is worth knowing because it is a second source for the same fact. Where a road's classification is genuinely in doubt — and on rural roads it sometimes is — being able to check it against two independent records is more useful than arguing about it.
What to do with this before laying anything out
- Find the road's functional classification before designing anything, because the width range follows from the class rather than from the traffic you expect.
- Assume the upper end of the range up here rather than the lower, since snow storage is named as a reason for additional width in exactly this area.
- If you are planning to rely on the 50-foot minimum, check both conditions: fewer than 150 vehicles per day now, and no future potential of higher volume.
- Set fences at least five feet beyond the toe of slope, and measure it from the toe rather than from the pavement or the boundary.
- Look at cut and fill sections and steep slopes separately, because each is independently a reason for more width.
- Cross-check the classification against the Idaho Transportation Department map if anything about it is unclear.
- Remember these are recommended widths in a county standard, so treat them as the starting point for a conversation with Public Works rather than as the final answer for a specific site.
The practical lesson is that a road here is wider than a road of the same class further south, and the reason is entirely about winter. Anyone who has watched a plow throw a berm knows where that width goes — and anyone who has replaced a fence knows what happens when it is not there. It is the same seasonal arithmetic that governs how snow removal gets contracted and whether the county plows your road at all, and it is worth building into a layout at the start rather than discovering in February.
Common questions
How wide does a county road right-of-way have to be?
Fremont County's recommended minimums are 120 feet for principal arterials, 80 to 100 feet for minor arterials, 70 to 90 feet for collectors, 60 to 80 feet for local roads, and 50 to 70 feet for subdivision roads.
Why do Island Park roads need extra width?
The code states that additional right-of-way width may be required in the north County — naming Ashton and Island Park — to allow for storage of plowed snow. The right-of-way is sized for the traffic plus the winter.
What else can require additional right-of-way width?
The table's footnote names higher traffic corridors, accommodation of extreme cut or fill sections, steep slopes, snow storage, and other site-specific considerations.
How far back from the road should a fence go?
The code says fences should be constructed at least five feet beyond the toe of slope, to prevent damage to the fence from plowed snow. The measurement is from the toe of slope rather than from the pavement edge or the property line.
Can I use the 50-foot minimum right-of-way?
Only in limited circumstances. Only low volume roads carrying fewer than 150 vehicles per day that have no future potential of higher volume may be eligible for the minimum 50-foot width, so both conditions have to hold.
How are Fremont County roads classified?
All roadways are classified in accordance with the appropriate Federal Highway Administration legislation, and all streets and highways are functionally classified as arterials, collectors, or local roads.
Where can I find out my road's classification?
The Fremont County Transportation Plan describes the categories and carries a Functional Classification System Map. A map showing the functional classifications can also be obtained from the Idaho Transportation Department.
Are these widths mandatory?
The code calls them recommended widths and gives ranges for every class except principal arterials. They are the starting point for a specific site rather than a fixed requirement, and site conditions push a road toward the upper end.
Does snow storage really change road design?
In this county it is written into the standard. Snow storage appears both in the north-county provision for additional width and in the footnote listing reasons a road may need more right-of-way than its class suggests.