By Kjel Jones, independent excavation & dirt-work researcher for Island Park · licensed Idaho real estate agent, LPT Realty

Published 2026-09-12

On a county road, your driveway keeps its distance: 125 feet from an intersection, 50 from the neighbour’s.

The county road has its own spacing numbers, and they are not the state’s

This site has already covered how far apart driveways must be on US-20, because the state highway runs the length of Island Park and the state’s table starts at 650 feet. But most approaches in this county are not onto US-20. They are onto county roads, and Appendix B of the Development Code carries a different, shorter set of distances for those:

“All approaches shall be, for local roads, a minimum of 125 feet from any intersection, measured from the intersection right-of-way to the edge of the approach; 155 feet for collector roads; and 200 feet for arterial roads. These distances may be increased based on factors such as type of facility and amount of traffic expected to be generated. Private approaches may be a minimum of 50 feet apart. See Fremont County Transportation Plan (2006), as may be amended, for access spacing guidelines.”

— Fremont County Development Code, 2011 Edition (Ordinance 2011-04), Appendix B, section 1.10.020. Consolidated through Ordinance 2026-03. Retrieved 7 September 2026

Three numbers, one per road class, and a floor of 50 feet between neighbouring private approaches. The measurement is specific enough to check with a tape: from the intersection’s right-of-way line to the near edge of the approach. And every distance can move upward with the traffic the use will generate — the code says so in the same breath.

Which number applies: the road class decides

The three figures are selected by the functional class of the road you are accessing:

Two cautions keep this honest. First, the 200 feet here is a distance from an intersection — it is not the 200 feet of sight distance in the county’s access standard, which is a different measure entirely. Second, road class is the county’s functional classification, not something readable off the pavement; the same classification system behind the right-of-way width table decides this table too.

What the road itself is allowed to do: Table 2

The same section of Appendix B fixes the geometry of the roads those approaches connect to — the alignment limits a county-standard road is designed within:

The curvature row is in degrees of curvature, the surveyor’s measure of how hard a curve turns — lower is gentler. The minimum-radius figures behind those degrees run from 340 feet at 35 mph on an arterial up to 1,330 feet at 60 mph, with local roads allowed down to 154 at 25 mph.

Two footnotes carry practical weight for anyone building or living on one of these roads:

• Roads built with curb and gutter may use a minimum grade of 0.35% instead of 0.5% — flat pavement drains only if it is not quite flat.
• The local-road grade maximum may be increased to 10% “with special attention to maintenance consequences.” That phrase is doing heavy winter work: a 10% grade is a road that a plow climbs with chains and that a loaded truck descends on the engine. The county permits it; the code is honest about who pays for it later.

That maintenance sentence is the one to read twice before buying ground at the top of a steep new road. It is the county warning, in its own standard, that steeper-than-8% is buildable and then plowed on somebody’s judgment every winter — and grade interacts with drainage the same way it does for the ditch and culvert rules on steeper ground.

Why 50 feet between private approaches matters on subdivided ground

The minimum between two private approaches — 50 feet — is the number that shapes shared ground. It sets how close two neighbours’ driveways may sit, and therefore how many separate accesses a stretch of frontage can legally carry:

• On a 300-foot shared boundary, the 50-foot floor allows at most a handful of separate approaches — and each must also clear the intersection distance for its road class.
• A private collector driveway — one access serving several dwellings, a class the county’s access standard recognizes — is the designed answer to that squeeze.
• The distances may be increased by traffic generation, so a commercial or multi-lot use should expect more than the minimum even where the tape measure says the minimum fits.

Put plainly: spacing is cheap to check at the sketch stage and expensive to discover at the permit stage. The tape measures two things — intersection distance for the road class, and separation from the neighbour’s approach — and both take ten minutes on the ground before anyone prices an approach anywhere near a highway.

Checking a lot’s access before you commit

1. Identify the road class — local, collector, or arterial — rather than guessing from traffic; the class sets 125, 155, or 200 feet.
2. Measure from the intersection right-of-way line to the nearest edge of the proposed approach, which is the measurement the code specifies.
3. Measure to the neighbour’s existing approach as well: private approaches may be a minimum of 50 feet apart.
4. Walk the road’s grade and curves against Table 2 — a road already pushing 8% or a hard curve is context for where an approach can safely sit.
5. Expect the minimum to grow with the traffic the use generates; the code says the distances may be increased on those factors.
6. Check the Fremont County Transportation Plan (2006, as amended) — the code itself points to it for access spacing guidelines beyond these floors.
7. If the frontage cannot satisfy the distances, ask about a shared private collector approach before assuming the lot has no access.

None of these numbers is hidden — they sit on one page of a public code, in the same appendix as the cross-section recipe. What makes them valuable is that they are measured before purchase, in minutes, and they decide something no amount of dirt work can fix afterward.

Common questions

How far must a driveway be from an intersection on a county road?

For local roads, a minimum of 125 feet, measured from the intersection right-of-way to the edge of the approach; 155 feet for collector roads; and 200 feet for arterial roads.

How is the distance from an intersection measured?

From the intersection right-of-way line to the nearest edge of the approach. It is a boundary-to-driveway measurement, not a sight-distance measurement.

How far apart can two neighbouring driveways be on a county road?

Private approaches may be a minimum of 50 feet apart. The intersection distances are separate and additional — an approach must satisfy both its road-class distance from the intersection and the 50-foot separation from other private approaches.

Can the county require more than these minimum distances?

Yes. The code states the distances may be increased based on factors such as the type of facility and the amount of traffic expected to be generated.

What is the steepest grade a county road can have?

Table 2 sets a maximum vertical grade of 6% on arterials and collectors and 8% on local roads. The local maximum may be increased to 10% with special attention to maintenance consequences.

What is the minimum grade on a county road?

0.5%, except that roadways constructed with curb and gutter sections may have a minimum grade of 0.35%. Below that, pavement does not drain.

At what angle must roads intersect?

Angles of intersection from 85 to 95 degrees for all three road classes in Table 2 — roads meet essentially square.

How fast are county roads designed for?

Design speeds run 35 to 60 mph on arterials, 35 to 50 mph on collectors, and 25 to 45 mph on local roads, with superelevation on curves limited to 0.06 feet per foot.

Where else are access spacing guidelines written down?

The code points to the Fremont County Transportation Plan (2006), as it may be amended, for access spacing guidelines beyond the minimum distances in section 1.10.020.