Official sources do not support calling one Nampa road the city’s “most dangerous.” The latest adopted regional high-injury analysis, published by COMPASS in 2025 from 2018–2022 Idaho crash records, identifies three Nampa-area corridor segments with elevated fatal-or-serious-injury crash histories. Garrity Boulevard from 11th Avenue to I-84 has the highest count in that table. These are historical planning measures, not forecasts of where a crash will occur. Below are the data, limits, and current city project updates.
What the latest official Nampa corridor data shows
The Community Planning Association of Southwest Idaho (COMPASS) accepted its Regional Safety Action Plan in February 2025. Its source analysis uses five calendar years of Idaho crash records, 2018 through 2022. Appendix D of the plan’s strategy memorandum lists the following Nampa-area segments among the region’s high fatal-and-serious-injury crash locations.
| Corridor limits | Source classification / owner | Fatal + serious-injury crashes | Approx. miles | Crashes per mile |
|---|---|---|---|---|
| Garrity Boulevard, 11th Avenue to I-84 | Nampa / ITD | 21 | 2.2 | 9.5 |
| State Highway 45, Roosevelt Avenue to Greenhurst Road | Nampa/Melba / ITD | 14 | 1.5 | 9.3 |
| Caldwell Boulevard, Orchard Avenue to Middleton Road | Nampa / ITD | 11 | 2.2 | 5.0 |
Measure: “K/A crashes” means crashes classified as fatal (K) or serious injury (A). “Crashes per mile” divides that five-year crash count by the corridor’s approximate mileage. It is not a rate per driver, trip, vehicle-mile, or traffic volume.
Data-quality note: The memorandum’s Appendix D segment table reports 21 K/A crashes for the stated Garrity Boulevard limits. A later strategy row in the same memorandum says 30 without explaining the difference. This guide uses the Appendix D table value and discloses the conflict instead of guessing which unpublished adjustment produced the second number.
Why this is a corridor watchlist—not a “most dangerous roads” ranking
The source does not cover every Nampa street
COMPASS limited the network analysis to collectors and higher roadway classes. It removed local roads, interstates, and ramps from High Injury Network development. Regionwide, 148 fatal or serious-injury crashes were also excluded because they were on local roads or outside the buffered network features; the memorandum says 13 of those records may have been poorly geocoded. A list built from that filtered network cannot rank every road in Nampa.
Counts and distance-normalized figures answer different questions
The crash count is the numerator for the five-year period. Corridor miles are the denominator for the published per-mile figure. That comparison controls for approximate segment length, but not for exposure: the number of vehicles, trips, or vehicle-miles on each road. Although the methodology describes joining traffic-volume data, its data dictionary marks the crash-rate fields as not quality-controlled or verified. We therefore do not republish an exposure rate or call the table a probability ranking.
A location association is not a finding of causation
The analysis assigned a crash within 150 feet of a junction to the junction layer; other crashes went to the nearest roadway segment. COMPASS also warns that correlation between a roadway characteristic and severe crashes does not prove the characteristic caused a collision. For statewide context on the difference between a reported contributing factor and a legal cause, see our Idaho crash-causes data guide.
Newer Nampa project data uses different boundaries and measures
Newer City of Nampa notices add useful project context, but they should not be spliced into the 2018–2022 severe-crash table. The city notices publish crash counts without a severity definition and use different corridor limits.
| City project | Published crash context | What the current source supports |
|---|---|---|
| Northside Boulevard, North Yale Street, and 7th Street South study, from 2nd Street South to 12th Avenue | 305 crashes in 2020–2024; 81% occurred at intersections | A July 7, 2025 city notice documents the study limits, exact five-year window, and alternatives process. It does not publish a severity split or traffic-volume rate. |
| Northside corridor BUILD project, from Northside Boulevard/4th Street North 1.5 miles south to 12th Avenue South/7th Street South | The city says 350 crashes in the “past five years,” but does not name the start and end years | A July 8, 2026 city announcement reports a $23 million grant, a first phase potentially beginning in fiscal year 2027, and a September 30, 2030 completion target. The undated five-year count is project context, not a ranking input. |
Project status can change. The city’s current transportation studies page is the appropriate place to check for new notices rather than assuming that an announced concept, funded project, or construction phase is complete.
What to document after a crash on a Nampa corridor
These historical tables do not decide who caused a particular collision. Signal phase, right of way, lane position, speed evidence, visibility, vehicle data, witness accounts, video, and the conduct of each road user can matter. A citation or crash report is evidence, but it is not a civil judgment. Our guide to how fault is determined in an Idaho car accident explains that process.
- Call 911 when someone may be injured or the scene is unsafe.
- If it is safe, photograph vehicle positions, lane markings, signs, signals, sight obstructions, debris, and temporary construction controls.
- Record the exact direction of travel, lane, time, and weather; do not rely only on a nearby business name.
- Save dash-camera files promptly and identify nearby doorbell, traffic, or business cameras whose recordings may be overwritten.
- Use the correct agency channel when obtaining the report; our Nampa crash-report guide distinguishes the likely record holders.
If you need help evaluating evidence after an injury crash, our Idaho car-accident attorneys can explain the process. A consultation is not a promise about fault, compensation, or outcome; the facts and available evidence control. You may request a case review when you are ready.
Methodology and update schedule
- Primary crash source: Idaho crash records analyzed by COMPASS for 2018–2022.
- Geography: Only Appendix D rows labeled Nampa or Nampa/Melba; the source’s corridor endpoints and ownership labels are preserved.
- Selection: Non-comprehensive watchlist of the Nampa-area segments in COMPASS’s high-K/A location table; not a ranking of all city streets.
- Calculations: Published K/A crashes per approximate mile; the accompanying chart-ready file also divides each count by five for an annualized historical count, clearly labeled as not exposure-normalized.
- Last data check: September 2, 2026.
- Review owner: Attorneys of Idaho content operations.
- Next scheduled check: June 30, 2027, or earlier if COMPASS or ITD publishes a replacement High Injury Network dataset.
Download the Attorneys of Idaho companion files: Nampa 2018–2022 severe-crash corridor comparison CSV, Nampa current-project context CSV, and Nampa research methodology CSV. These Attorneys of Idaho research companions organize information from the cited sources; they are not official agency datasets or raw crash records.
Sources and Legal References
- COMPASS, Regional Safety Action Plan (current plan page; accepted February 2025; page updated May 4, 2026).
- COMPASS Technical Memorandum 3: Existing Conditions (October 8, 2024; 2018–2022 data, methods, exclusions, and definitions).
- COMPASS Technical Memorandum 4: Strategy Development (September 16, 2024; Appendix D tables and jurisdiction strategies).
- City of Nampa, Northside/Yale/7th proposed safety improvements (July 7, 2025).
- City of Nampa, $23 million transportation grant announcement (July 8, 2026).
- City of Nampa, current surveys and studies (project-status index checked September 2, 2026).
This article provides general information, not legal advice. Crash histories and project plans can change, and a location-level statistic does not establish fault in an individual case.
Legal review
Legal reviewer
Reviewed by J.W. Bond , Founding Attorney and Partner on September 2, 2026.