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Idaho Shoulder Closure Traffic Control Plan
A shoulder closure keeps every through lane open. You taper channelizing devices onto the shoulder, post advance warning, and nobody changes lanes. The numbers below are computed for Idaho from MUTCD 11th Edition Part 6 — taper length, advance sign spacing, buffer, and device count at four posted speeds.
Real MUTCD dimensions, a title block, and a printable sheet — no account, no cost.
Build this plan free — takes about 2 minutesComputed MUTCD dimensions
Governing typical application: TA-3 — Work on the Shoulders. Assumptions: urban collector, 2 through lanes, 12 ft lanes, 8 ft lateral offset, 100 ft work space, short-term duration. Rule set MUTCD 11th Ed. + 50-state/DC adoption layer + ID/ACHD profiles, rule set 2026-08 rev 4.
| Posted speed | Taper length (shoulder) | Advance signs A / B / C | Longitudinal buffer | Device spacing taper / tangent | Channelizing devices |
|---|---|---|---|---|---|
| 25 mph | 30 ft | 100 ft / 100 ft / 100 ft | 155 ft | 25 ft / 50 ft | 15 |
| 35 mph | 55 ft | 250 ft / 250 ft / 250 ft | 250 ft | 35 ft / 70 ft | 13 |
| 45 mph | 120 ft | 350 ft / 350 ft / 350 ft | 360 ft | 45 ft / 90 ft | 15 |
| 55 mph | 150 ft | 350 ft / 350 ft / 350 ft | 495 ft | 55 ft / 110 ft | 14 |
What applies in Idaho
- Agency rule set
- State of Idaho (MUTCD as adopted)
- MUTCD adoption
- National MUTCD adopted with a state supplement (cross-checked against a second source)
Printed on every Idaho sheet:
- Idaho has adopted the national MUTCD for use on Idaho highways and streets; the national Part 6 requirements apply unless the local highway authority has modified them.
This rule set holds no Idaho-specific permit form, review time, or closure-hour restriction, so none is shown. Those are set by whoever owns the road — state DOT, county, city, or highway district — and have to come from them.
Governing citation: Idaho Code §49-201(3) — the Idaho Transportation Board shall adopt a manual of traffic-control devices correlating with and conforming to the most recent edition of the national MUTCD; implemented by IDAPA 39.03.41 “Rules Governing Traffic Control Devices,” which adopts the MUTCD for use in Idaho. See also Idaho Code §49-209 (local traffic-control devices) for city and highway-district authority, and the ITD Traffic Manual Idaho Supplement for state-highway modifications.
Questions people actually ask
How long does a shoulder taper have to be in Idaho?
MUTCD sets the shoulder taper at one third of the merging taper length for the same offset and posted speed. The table above shows the computed length at 25, 35, 45, and 55 mph for an 8 ft shoulder. Change the offset or the speed in the builder and the number recomputes.
Do I need a permit to close a shoulder?
Usually yes, and it depends entirely on who owns the road — state DOT, county, city, or a highway district. This tool records the agency information it can stand behind and says so where it cannot; it does not guess at a permit desk. Call the road authority for the segment you are working on.
Is a generated sheet good enough to submit?
It is a planning sheet, not an approved plan. It gives a reviewer real MUTCD dimensions and a governing typical application to check against, which is far better than a hand sketch — but a qualified person has to review it and adapt it to field conditions, and the permitting agency has the last word.
Real MUTCD dimensions, a title block, and a printable sheet — no account, no cost.
Build this plan free — takes about 2 minutesDISCLAIMER — READ BEFORE USE
This traffic control plan was generated by an automated tool for planning and reference purposes only. It is based on the MUTCD 11th Edition Part 6 typical applications and the agency rule set selected above. It is not a certified, sealed, or professionally engineered document and has not been reviewed against actual field conditions at this site. It must be reviewed, adapted to field conditions, and approved by a qualified person — and, where required, by the permitting agency and/or a licensed Professional Engineer — before use. Field conditions govern. The user is solely responsible for work-zone safety, for conformance with all applicable federal, state, and local requirements, and for obtaining all required permits. PM Axsus disclaims all liability arising from use of this document.