Road Risk Results
Results from 501,961 complete mapped road sections
Model 3.2 calculations across selected mapped road sections in all 26 counties.
Provisional Results
Model 3.2.0 · controlled preview
- Average comparative output
Weighted by represented section length - 0.606%
- Across 44,493.981 km of represented centreline, from 501,961 complete sections.
- Lowest section output
- 0.0066%Anonymous minimum · section ACI
- Highest section output
- 23.7193%Anonymous maximum · section ACI
- Median output
- 0.332%P50 · weighted by length
- 95th percentile
- 2.226%P95 · weighted by length
- Complete sections
- 501,961From wholly qualifying mapped parts
- Represented length
- 44,493.981 kmMapped centreline length
Annual Comparative Index (ACI) is Road Risk’s comparative model output, displayed as a percentage.
These results describe selected mapped road sections under stated assumptions. They are not collision probabilities, official safety ratings or representative estimates for all Irish roads.
Completed frozen inventory
Every selected part has a recorded outcome
All 1,419,158 eligible mapped parts were processed. The headline statistics use only 318,898 wholly qualifying parts and all 501,961 of their complete sections.
- 1,419,158Frozen eligible mapped parts
- 100%Received a recorded outcome, including partial and unavailable results
- 22.5%Of processed parts passed every whole-parent requirement
- 501,961Complete sections contribute to this report
Processing coverage is not measured-input completeness. A road part can have an ACI output but lack another required supporting comparison. In particular, near-straight geometry may intentionally lack a curve/friction comparison and therefore fall outside this strict collection.
The distribution
How the section outputs are distributed
Each bar shows the share of represented centreline length in an ACI range. Longer sections contribute more than shorter sections. These are output ranges, not safety categories.
About 63.1% of the represented length has an output below 0.5%. The upper ranges remain included in both the chart and the average.
View exact distribution values and section counts
| ACI range | Sections | Length | Length share |
|---|---|---|---|
| Below 0.1% | 86,086 | 7,706.718 km | 17.321% |
| 0.1–0.2% | 85,803 | 7,682.610 km | 17.267% |
| 0.2–0.5% | 143,961 | 12,678.414 km | 28.495% |
| 0.5–1% | 108,320 | 9,367.447 km | 21.053% |
| 1–2% | 47,684 | 4,325.416 km | 9.721% |
| 2–5% | 27,666 | 2,516.449 km | 5.656% |
| 5% and above | 2,441 | 216.926 km | 0.488% |
Intervals include their lower boundary and exclude their upper boundary. The final range includes every value at or above 5%. Unequal interval widths are shown as labelled range bars, not probability density.
The middle and the upper tail
Reading the percentiles and the range
Percentiles describe represented length, not the percentage of roads. The average is higher than the median because the larger outputs pull it upward.
- Median · P50
- 0.332%
Half of the represented length has an output at or below this value.
- P90
- 1.445%
90% of the represented length has an output at or below this value.
- P95
- 2.226%
95% of the represented length has an output at or below this value.
- P99
- 3.845%
99% of the represented length has an output at or below this value.
Lowest: 0.0066%
The minimum reflects the model’s baseline assumptions within this collection. It is not a physical minimum collision rate or proof that a road is safe.
Highest: 23.7193%
This is the exact section output before display rounding or colour clipping. Technical inspection checks geometry, speed assumptions, traffic proxies, junction context and intermediate clamps; it does not establish equivalent real-world danger.
6.143% of represented length exceeds the App’s 2% colour-display maximum. That limit is a display setting, not a safety threshold. The numerical outputs remain intact.
View additional numerical precision
| Measure | Percentage |
|---|---|
| Length-weighted average | 0.605924% |
| Minimum | 0.006600% |
| Maximum | 23.719332% |
| P50 | 0.332089% |
| P90 | 1.444955% |
| P95 | 2.225685% |
| P99 | 3.845399% |
The download retains full numerical precision as fractional ACI. Percentages on this page are converted once for display.
Geographic coverage
Sections from all 26 counties
318,898 mapped road parts contribute the 501,961 complete sections. A mapped part is not necessarily an entire named road. The table is alphabetical; bars compare represented length, not percentage scanned or county danger.
Open any county for its processing, qualification and input assumptions. These are coverage summaries, not county risk rankings. Whole road parts are assigned once under the frozen county method; a crossing part’s centreline can extend beyond its assigned county.
8 counties meet the preferred 75% Donegal comparison on both complete-section count and represented length; 5 meet 50% but not 75%. The remaining 13 are full-inventory exceptions, with every eligible part processed but the absolute comparison unmet.
Carlow5,227complete sections469.667 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 13,967
- Processed parts
- 13,967 · 100% of eligible parts
- Wholly qualifying parts
- 3,201 · 22.9% of processed parts
- Complete retained sections
- 5,227 · 469.667 km
- Complete ACI coverage
- 9,293 parts · 66.5% of processed parts
- Partial ACI coverage
- 34 parts · 0.2% of processed parts
- No available ACI output
- 4,640 parts · 33.2% of processed parts
Compared with the fixed Donegal reference
17.2% of its 30,441 complete sections; 17.2% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (5,227 of 5,227).
- Road-class speed assumption: 73.2% of retained sections (3,827 of 5,227).
- Surface information not recorded: 75.8% of retained sections (3,961 of 5,227).
- Road-class traffic proxy: 100.0% of retained sections (5,227 of 5,227).
- Typical scenario assumptions: 100.0% of retained sections (5,227 of 5,227).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 4,640 mapped parts, containing 4,640 sections.
- Partially available output: 34 mapped parts, containing 112 sections.
- A section does not meet trace requirements: 3,687 mapped parts, containing 6,890 sections.
- A required primary comparison is unavailable: 2,405 mapped parts, containing 8,049 sections.
Cavan20,642complete sections1,890.736 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 37,606
- Processed parts
- 37,606 · 100% of eligible parts
- Wholly qualifying parts
- 11,368 · 30.2% of processed parts
- Complete retained sections
- 20,642 · 1,890.736 km
- Complete ACI coverage
- 27,998 parts · 74.5% of processed parts
- Partial ACI coverage
- 164 parts · 0.4% of processed parts
- No available ACI output
- 9,444 parts · 25.1% of processed parts
Compared with the fixed Donegal reference
67.8% of its 30,441 complete sections; 69.1% of its 2,735.066 km represented length.
Minimum comparison met; preferred comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (20,642 of 20,642).
- Road-class speed assumption: 78.0% of retained sections (16,103 of 20,642).
- Surface information not recorded: 76.1% of retained sections (15,708 of 20,642).
- Road-class traffic proxy: 100.0% of retained sections (20,642 of 20,642).
- Typical scenario assumptions: 100.0% of retained sections (20,642 of 20,642).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 9,444 mapped parts, containing 9,444 sections.
- Partially available output: 164 mapped parts, containing 536 sections.
- A section does not meet trace requirements: 10,069 mapped parts, containing 18,437 sections.
- A required primary comparison is unavailable: 6,561 mapped parts, containing 17,165 sections.
Clare12,686complete sections1,137.665 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 32,189
- Processed parts
- 32,189 · 100% of eligible parts
- Wholly qualifying parts
- 7,591 · 23.6% of processed parts
- Complete retained sections
- 12,686 · 1,137.665 km
- Complete ACI coverage
- 23,644 parts · 73.5% of processed parts
- Partial ACI coverage
- 101 parts · 0.3% of processed parts
- No available ACI output
- 8,444 parts · 26.2% of processed parts
Compared with the fixed Donegal reference
41.7% of its 30,441 complete sections; 41.6% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (12,686 of 12,686).
- Road-class speed assumption: 89.9% of retained sections (11,399 of 12,686).
- Surface information not recorded: 74.6% of retained sections (9,468 of 12,686).
- Road-class traffic proxy: 100.0% of retained sections (12,686 of 12,686).
- Typical scenario assumptions: 100.0% of retained sections (12,686 of 12,686).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 8,444 mapped parts, containing 8,444 sections.
- Partially available output: 101 mapped parts, containing 335 sections.
- A section does not meet trace requirements: 9,574 mapped parts, containing 19,185 sections.
- A required primary comparison is unavailable: 6,479 mapped parts, containing 29,026 sections.
Cork66,938complete sections6,025.770 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 188,548
- Processed parts
- 188,548 · 100% of eligible parts
- Wholly qualifying parts
- 37,876 · 20.1% of processed parts
- Complete retained sections
- 66,938 · 6,025.770 km
- Complete ACI coverage
- 97,897 parts · 51.9% of processed parts
- Partial ACI coverage
- 554 parts · 0.3% of processed parts
- No available ACI output
- 90,097 parts · 47.8% of processed parts
Compared with the fixed Donegal reference
219.9% of its 30,441 complete sections; 220.3% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (66,938 of 66,938).
- Road-class speed assumption: 84.8% of retained sections (56,748 of 66,938).
- Surface information not recorded: 77.1% of retained sections (51,581 of 66,938).
- Road-class traffic proxy: 100.0% of retained sections (66,938 of 66,938).
- Typical scenario assumptions: 100.0% of retained sections (66,938 of 66,938).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 90,097 mapped parts, containing 90,097 sections.
- Partially available output: 554 mapped parts, containing 2,104 sections.
- A section does not meet trace requirements: 41,449 mapped parts, containing 71,688 sections.
- A required primary comparison is unavailable: 18,572 mapped parts, containing 64,416 sections.
Donegal30,441complete sections2,735.066 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 65,750
- Processed parts
- 65,750 · 100% of eligible parts
- Wholly qualifying parts
- 17,328 · 26.4% of processed parts
- Complete retained sections
- 30,441 · 2,735.066 km
- Complete ACI coverage
- 45,094 parts · 68.6% of processed parts
- Partial ACI coverage
- 224 parts · 0.3% of processed parts
- No available ACI output
- 20,432 parts · 31.1% of processed parts
Compared with the fixed Donegal reference
100.0% of its 30,441 complete sections; 100.0% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (30,441 of 30,441).
- Road-class speed assumption: 76.0% of retained sections (23,123 of 30,441).
- Surface information not recorded: 82.1% of retained sections (24,977 of 30,441).
- Road-class traffic proxy: 100.0% of retained sections (30,441 of 30,441).
- Typical scenario assumptions: 100.0% of retained sections (30,441 of 30,441).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 20,432 mapped parts, containing 20,432 sections.
- Partially available output: 224 mapped parts, containing 766 sections.
- A section does not meet trace requirements: 18,674 mapped parts, containing 33,898 sections.
- A required primary comparison is unavailable: 9,092 mapped parts, containing 34,493 sections.
Dublin31,309complete sections2,584.801 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 175,903
- Processed parts
- 175,903 · 100% of eligible parts
- Wholly qualifying parts
- 26,657 · 15.2% of processed parts
- Complete retained sections
- 31,309 · 2,584.801 km
- Complete ACI coverage
- 80,397 parts · 45.7% of processed parts
- Partial ACI coverage
- 197 parts · 0.1% of processed parts
- No available ACI output
- 95,309 parts · 54.2% of processed parts
Compared with the fixed Donegal reference
102.9% of its 30,441 complete sections; 94.5% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (31,309 of 31,309).
- Road-class speed assumption: 35.9% of retained sections (11,244 of 31,309).
- Surface information not recorded: 31.1% of retained sections (9,728 of 31,309).
- Road-class traffic proxy: 100.0% of retained sections (31,309 of 31,309).
- Typical scenario assumptions: 100.0% of retained sections (31,309 of 31,309).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 95,309 mapped parts, containing 95,309 sections.
- Partially available output: 197 mapped parts, containing 478 sections.
- A section does not meet trace requirements: 36,535 mapped parts, containing 43,293 sections.
- A required primary comparison is unavailable: 17,205 mapped parts, containing 24,387 sections.
Galway34,666complete sections3,094.510 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 82,891
- Processed parts
- 82,891 · 100% of eligible parts
- Wholly qualifying parts
- 21,149 · 25.5% of processed parts
- Complete retained sections
- 34,666 · 3,094.510 km
- Complete ACI coverage
- 56,996 parts · 68.8% of processed parts
- Partial ACI coverage
- 312 parts · 0.4% of processed parts
- No available ACI output
- 25,583 parts · 30.9% of processed parts
Compared with the fixed Donegal reference
113.9% of its 30,441 complete sections; 113.1% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (34,666 of 34,666).
- Road-class speed assumption: 82.9% of retained sections (28,748 of 34,666).
- Surface information not recorded: 71.5% of retained sections (24,770 of 34,666).
- Road-class traffic proxy: 100.0% of retained sections (34,666 of 34,666).
- Typical scenario assumptions: 100.0% of retained sections (34,666 of 34,666).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 25,583 mapped parts, containing 25,583 sections.
- Partially available output: 312 mapped parts, containing 1,164 sections.
- A section does not meet trace requirements: 22,523 mapped parts, containing 40,558 sections.
- A required primary comparison is unavailable: 13,324 mapped parts, containing 45,412 sections.
Kerry25,506complete sections2,276.865 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 61,180
- Processed parts
- 61,180 · 100% of eligible parts
- Wholly qualifying parts
- 15,297 · 25.0% of processed parts
- Complete retained sections
- 25,506 · 2,276.865 km
- Complete ACI coverage
- 44,544 parts · 72.8% of processed parts
- Partial ACI coverage
- 224 parts · 0.4% of processed parts
- No available ACI output
- 16,412 parts · 26.8% of processed parts
Compared with the fixed Donegal reference
83.8% of its 30,441 complete sections; 83.2% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (25,506 of 25,506).
- Road-class speed assumption: 90.6% of retained sections (23,121 of 25,506).
- Surface information not recorded: 80.2% of retained sections (20,467 of 25,506).
- Road-class traffic proxy: 100.0% of retained sections (25,506 of 25,506).
- Typical scenario assumptions: 100.0% of retained sections (25,506 of 25,506).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 16,412 mapped parts, containing 16,413 sections.
- Partially available output: 224 mapped parts, containing 797 sections.
- A section does not meet trace requirements: 18,615 mapped parts, containing 32,188 sections.
- A required primary comparison is unavailable: 10,632 mapped parts, containing 34,095 sections.
Kildare15,118complete sections1,298.659 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 54,837
- Processed parts
- 54,837 · 100% of eligible parts
- Wholly qualifying parts
- 11,507 · 21.0% of processed parts
- Complete retained sections
- 15,118 · 1,298.659 km
- Complete ACI coverage
- 34,170 parts · 62.3% of processed parts
- Partial ACI coverage
- 100 parts · 0.2% of processed parts
- No available ACI output
- 20,567 parts · 37.5% of processed parts
Compared with the fixed Donegal reference
49.7% of its 30,441 complete sections; 47.5% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (15,118 of 15,118).
- Road-class speed assumption: 80.7% of retained sections (12,207 of 15,118).
- Surface information not recorded: 73.7% of retained sections (11,137 of 15,118).
- Road-class traffic proxy: 100.0% of retained sections (15,118 of 15,118).
- Typical scenario assumptions: 100.0% of retained sections (15,118 of 15,118).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 20,567 mapped parts, containing 20,567 sections.
- Partially available output: 100 mapped parts, containing 282 sections.
- A section does not meet trace requirements: 14,221 mapped parts, containing 21,133 sections.
- A required primary comparison is unavailable: 8,442 mapped parts, containing 19,115 sections.
Kilkenny16,083complete sections1,423.224 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 42,982
- Processed parts
- 42,982 · 100% of eligible parts
- Wholly qualifying parts
- 10,456 · 24.3% of processed parts
- Complete retained sections
- 16,083 · 1,423.224 km
- Complete ACI coverage
- 29,965 parts · 69.7% of processed parts
- Partial ACI coverage
- 106 parts · 0.2% of processed parts
- No available ACI output
- 12,911 parts · 30.0% of processed parts
Compared with the fixed Donegal reference
52.8% of its 30,441 complete sections; 52.0% of its 2,735.066 km represented length.
Minimum comparison met; preferred comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (16,083 of 16,083).
- Road-class speed assumption: 45.4% of retained sections (7,306 of 16,083).
- Surface information not recorded: 74.0% of retained sections (11,898 of 16,083).
- Road-class traffic proxy: 100.0% of retained sections (16,083 of 16,083).
- Typical scenario assumptions: 100.0% of retained sections (16,083 of 16,083).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 12,911 mapped parts, containing 12,911 sections.
- Partially available output: 106 mapped parts, containing 299 sections.
- A section does not meet trace requirements: 12,945 mapped parts, containing 20,780 sections.
- A required primary comparison is unavailable: 6,564 mapped parts, containing 18,843 sections.
Laois10,846complete sections964.145 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 27,621
- Processed parts
- 27,621 · 100% of eligible parts
- Wholly qualifying parts
- 6,945 · 25.1% of processed parts
- Complete retained sections
- 10,846 · 964.145 km
- Complete ACI coverage
- 20,226 parts · 73.2% of processed parts
- Partial ACI coverage
- 94 parts · 0.3% of processed parts
- No available ACI output
- 7,301 parts · 26.4% of processed parts
Compared with the fixed Donegal reference
35.6% of its 30,441 complete sections; 35.3% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (10,846 of 10,846).
- Road-class speed assumption: 53.5% of retained sections (5,804 of 10,846).
- Surface information not recorded: 79.8% of retained sections (8,658 of 10,846).
- Road-class traffic proxy: 100.0% of retained sections (10,846 of 10,846).
- Typical scenario assumptions: 100.0% of retained sections (10,846 of 10,846).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 7,301 mapped parts, containing 7,301 sections.
- Partially available output: 94 mapped parts, containing 320 sections.
- A section does not meet trace requirements: 7,895 mapped parts, containing 13,790 sections.
- A required primary comparison is unavailable: 5,386 mapped parts, containing 15,176 sections.
Leitrim12,162complete sections1,118.750 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 21,484
- Processed parts
- 21,484 · 100% of eligible parts
- Wholly qualifying parts
- 6,463 · 30.1% of processed parts
- Complete retained sections
- 12,162 · 1,118.750 km
- Complete ACI coverage
- 15,696 parts · 73.1% of processed parts
- Partial ACI coverage
- 102 parts · 0.5% of processed parts
- No available ACI output
- 5,686 parts · 26.5% of processed parts
Compared with the fixed Donegal reference
40.0% of its 30,441 complete sections; 40.9% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (12,162 of 12,162).
- Road-class speed assumption: 66.7% of retained sections (8,112 of 12,162).
- Surface information not recorded: 77.9% of retained sections (9,471 of 12,162).
- Road-class traffic proxy: 100.0% of retained sections (12,162 of 12,162).
- Typical scenario assumptions: 100.0% of retained sections (12,162 of 12,162).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 5,686 mapped parts, containing 5,686 sections.
- Partially available output: 102 mapped parts, containing 361 sections.
- A section does not meet trace requirements: 5,527 mapped parts, containing 10,896 sections.
- A required primary comparison is unavailable: 3,706 mapped parts, containing 10,865 sections.
Limerick14,308complete sections1,280.758 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 46,212
- Processed parts
- 46,212 · 100% of eligible parts
- Wholly qualifying parts
- 8,729 · 18.9% of processed parts
- Complete retained sections
- 14,308 · 1,280.758 km
- Complete ACI coverage
- 27,124 parts · 58.7% of processed parts
- Partial ACI coverage
- 141 parts · 0.3% of processed parts
- No available ACI output
- 18,947 parts · 41.0% of processed parts
Compared with the fixed Donegal reference
47.0% of its 30,441 complete sections; 46.8% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (14,308 of 14,308).
- Road-class speed assumption: 85.4% of retained sections (12,221 of 14,308).
- Surface information not recorded: 74.6% of retained sections (10,668 of 14,308).
- Road-class traffic proxy: 100.0% of retained sections (14,308 of 14,308).
- Typical scenario assumptions: 100.0% of retained sections (14,308 of 14,308).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 18,947 mapped parts, containing 18,947 sections.
- Partially available output: 141 mapped parts, containing 583 sections.
- A section does not meet trace requirements: 10,655 mapped parts, containing 20,656 sections.
- A required primary comparison is unavailable: 7,740 mapped parts, containing 26,881 sections.
Longford3,284complete sections301.211 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 7,336
- Processed parts
- 7,336 · 100% of eligible parts
- Wholly qualifying parts
- 1,711 · 23.3% of processed parts
- Complete retained sections
- 3,284 · 301.211 km
- Complete ACI coverage
- 5,705 parts · 77.8% of processed parts
- Partial ACI coverage
- 27 parts · 0.4% of processed parts
- No available ACI output
- 1,604 parts · 21.9% of processed parts
Compared with the fixed Donegal reference
10.8% of its 30,441 complete sections; 11.0% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (3,284 of 3,284).
- Road-class speed assumption: 77.5% of retained sections (2,545 of 3,284).
- Surface information not recorded: 70.1% of retained sections (2,303 of 3,284).
- Road-class traffic proxy: 100.0% of retained sections (3,284 of 3,284).
- Typical scenario assumptions: 100.0% of retained sections (3,284 of 3,284).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 1,604 mapped parts, containing 1,604 sections.
- Partially available output: 27 mapped parts, containing 165 sections.
- A section does not meet trace requirements: 1,973 mapped parts, containing 5,713 sections.
- A required primary comparison is unavailable: 2,021 mapped parts, containing 10,367 sections.
Louth10,564complete sections897.241 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 34,177
- Processed parts
- 34,177 · 100% of eligible parts
- Wholly qualifying parts
- 8,096 · 23.7% of processed parts
- Complete retained sections
- 10,564 · 897.241 km
- Complete ACI coverage
- 23,095 parts · 67.6% of processed parts
- Partial ACI coverage
- 87 parts · 0.3% of processed parts
- No available ACI output
- 10,995 parts · 32.2% of processed parts
Compared with the fixed Donegal reference
34.7% of its 30,441 complete sections; 32.8% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (10,564 of 10,564).
- Road-class speed assumption: 63.1% of retained sections (6,662 of 10,564).
- Surface information not recorded: 73.7% of retained sections (7,786 of 10,564).
- Road-class traffic proxy: 100.0% of retained sections (10,564 of 10,564).
- Typical scenario assumptions: 100.0% of retained sections (10,564 of 10,564).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 10,995 mapped parts, containing 10,995 sections.
- Partially available output: 87 mapped parts, containing 231 sections.
- A section does not meet trace requirements: 10,408 mapped parts, containing 13,857 sections.
- A required primary comparison is unavailable: 4,591 mapped parts, containing 9,948 sections.
Mayo33,081complete sections2,928.015 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 75,804
- Processed parts
- 75,804 · 100% of eligible parts
- Wholly qualifying parts
- 21,412 · 28.2% of processed parts
- Complete retained sections
- 33,081 · 2,928.015 km
- Complete ACI coverage
- 57,318 parts · 75.6% of processed parts
- Partial ACI coverage
- 358 parts · 0.5% of processed parts
- No available ACI output
- 18,128 parts · 23.9% of processed parts
Compared with the fixed Donegal reference
108.7% of its 30,441 complete sections; 107.1% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (33,081 of 33,081).
- Road-class speed assumption: 81.6% of retained sections (27,005 of 33,081).
- Surface information not recorded: 84.2% of retained sections (27,853 of 33,081).
- Road-class traffic proxy: 100.0% of retained sections (33,081 of 33,081).
- Typical scenario assumptions: 100.0% of retained sections (33,081 of 33,081).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 18,128 mapped parts, containing 18,128 sections.
- Partially available output: 358 mapped parts, containing 1,134 sections.
- A section does not meet trace requirements: 22,317 mapped parts, containing 38,745 sections.
- A required primary comparison is unavailable: 13,589 mapped parts, containing 41,670 sections.
Meath20,545complete sections1,744.330 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 104,939
- Processed parts
- 104,939 · 100% of eligible parts
- Wholly qualifying parts
- 15,488 · 14.8% of processed parts
- Complete retained sections
- 20,545 · 1,744.330 km
- Complete ACI coverage
- 49,531 parts · 47.2% of processed parts
- Partial ACI coverage
- 159 parts · 0.2% of processed parts
- No available ACI output
- 55,249 parts · 52.6% of processed parts
Compared with the fixed Donegal reference
67.5% of its 30,441 complete sections; 63.8% of its 2,735.066 km represented length.
Minimum comparison met; preferred comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (20,545 of 20,545).
- Road-class speed assumption: 79.5% of retained sections (16,337 of 20,545).
- Surface information not recorded: 73.7% of retained sections (15,137 of 20,545).
- Road-class traffic proxy: 100.0% of retained sections (20,545 of 20,545).
- Typical scenario assumptions: 100.0% of retained sections (20,545 of 20,545).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 55,249 mapped parts, containing 55,249 sections.
- Partially available output: 159 mapped parts, containing 473 sections.
- A section does not meet trace requirements: 24,460 mapped parts, containing 32,540 sections.
- A required primary comparison is unavailable: 9,583 mapped parts, containing 21,038 sections.
Monaghan14,380complete sections1,314.812 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 25,399
- Processed parts
- 25,399 · 100% of eligible parts
- Wholly qualifying parts
- 7,945 · 31.3% of processed parts
- Complete retained sections
- 14,380 · 1,314.812 km
- Complete ACI coverage
- 19,599 parts · 77.2% of processed parts
- Partial ACI coverage
- 117 parts · 0.5% of processed parts
- No available ACI output
- 5,683 parts · 22.4% of processed parts
Compared with the fixed Donegal reference
47.2% of its 30,441 complete sections; 48.1% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (14,380 of 14,380).
- Road-class speed assumption: 63.3% of retained sections (9,096 of 14,380).
- Surface information not recorded: 56.8% of retained sections (8,172 of 14,380).
- Road-class traffic proxy: 100.0% of retained sections (14,380 of 14,380).
- Typical scenario assumptions: 100.0% of retained sections (14,380 of 14,380).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 5,683 mapped parts, containing 5,683 sections.
- Partially available output: 117 mapped parts, containing 473 sections.
- A section does not meet trace requirements: 6,853 mapped parts, containing 13,289 sections.
- A required primary comparison is unavailable: 4,801 mapped parts, containing 13,687 sections.
Offaly9,966complete sections880.859 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 26,868
- Processed parts
- 26,868 · 100% of eligible parts
- Wholly qualifying parts
- 6,554 · 24.4% of processed parts
- Complete retained sections
- 9,966 · 880.859 km
- Complete ACI coverage
- 20,064 parts · 74.7% of processed parts
- Partial ACI coverage
- 91 parts · 0.3% of processed parts
- No available ACI output
- 6,713 parts · 25.0% of processed parts
Compared with the fixed Donegal reference
32.7% of its 30,441 complete sections; 32.2% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (9,966 of 9,966).
- Road-class speed assumption: 50.5% of retained sections (5,033 of 9,966).
- Surface information not recorded: 60.5% of retained sections (6,025 of 9,966).
- Road-class traffic proxy: 100.0% of retained sections (9,966 of 9,966).
- Typical scenario assumptions: 100.0% of retained sections (9,966 of 9,966).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 6,713 mapped parts, containing 6,713 sections.
- Partially available output: 91 mapped parts, containing 352 sections.
- A section does not meet trace requirements: 8,110 mapped parts, containing 13,582 sections.
- A required primary comparison is unavailable: 5,400 mapped parts, containing 15,511 sections.
Roscommon12,181complete sections1,109.026 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 28,097
- Processed parts
- 28,097 · 100% of eligible parts
- Wholly qualifying parts
- 6,975 · 24.8% of processed parts
- Complete retained sections
- 12,181 · 1,109.026 km
- Complete ACI coverage
- 22,165 parts · 78.9% of processed parts
- Partial ACI coverage
- 115 parts · 0.4% of processed parts
- No available ACI output
- 5,817 parts · 20.7% of processed parts
Compared with the fixed Donegal reference
40.0% of its 30,441 complete sections; 40.5% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (12,181 of 12,181).
- Road-class speed assumption: 79.4% of retained sections (9,667 of 12,181).
- Surface information not recorded: 82.7% of retained sections (10,077 of 12,181).
- Road-class traffic proxy: 100.0% of retained sections (12,181 of 12,181).
- Typical scenario assumptions: 100.0% of retained sections (12,181 of 12,181).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 5,817 mapped parts, containing 5,817 sections.
- Partially available output: 115 mapped parts, containing 457 sections.
- A section does not meet trace requirements: 7,859 mapped parts, containing 16,680 sections.
- A required primary comparison is unavailable: 7,331 mapped parts, containing 25,270 sections.
Sligo9,249complete sections828.469 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 23,355
- Processed parts
- 23,355 · 100% of eligible parts
- Wholly qualifying parts
- 5,553 · 23.8% of processed parts
- Complete retained sections
- 9,249 · 828.469 km
- Complete ACI coverage
- 16,759 parts · 71.8% of processed parts
- Partial ACI coverage
- 74 parts · 0.3% of processed parts
- No available ACI output
- 6,522 parts · 27.9% of processed parts
Compared with the fixed Donegal reference
30.4% of its 30,441 complete sections; 30.3% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (9,249 of 9,249).
- Road-class speed assumption: 58.0% of retained sections (5,361 of 9,249).
- Surface information not recorded: 73.4% of retained sections (6,792 of 9,249).
- Road-class traffic proxy: 100.0% of retained sections (9,249 of 9,249).
- Typical scenario assumptions: 100.0% of retained sections (9,249 of 9,249).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 6,522 mapped parts, containing 6,522 sections.
- Partially available output: 74 mapped parts, containing 269 sections.
- A section does not meet trace requirements: 6,755 mapped parts, containing 13,156 sections.
- A required primary comparison is unavailable: 4,451 mapped parts, containing 16,798 sections.
Tipperary27,630complete sections2,489.287 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 64,570
- Processed parts
- 64,570 · 100% of eligible parts
- Wholly qualifying parts
- 16,889 · 26.2% of processed parts
- Complete retained sections
- 27,630 · 2,489.287 km
- Complete ACI coverage
- 47,713 parts · 73.9% of processed parts
- Partial ACI coverage
- 240 parts · 0.4% of processed parts
- No available ACI output
- 16,617 parts · 25.7% of processed parts
Compared with the fixed Donegal reference
90.8% of its 30,441 complete sections; 91.0% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (27,630 of 27,630).
- Road-class speed assumption: 87.4% of retained sections (24,151 of 27,630).
- Surface information not recorded: 83.3% of retained sections (23,018 of 27,630).
- Road-class traffic proxy: 100.0% of retained sections (27,630 of 27,630).
- Typical scenario assumptions: 100.0% of retained sections (27,630 of 27,630).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 16,617 mapped parts, containing 16,617 sections.
- Partially available output: 240 mapped parts, containing 737 sections.
- A section does not meet trace requirements: 18,352 mapped parts, containing 32,114 sections.
- A required primary comparison is unavailable: 12,472 mapped parts, containing 34,390 sections.
Waterford16,905complete sections1,474.928 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 47,837
- Processed parts
- 47,837 · 100% of eligible parts
- Wholly qualifying parts
- 11,369 · 23.8% of processed parts
- Complete retained sections
- 16,905 · 1,474.928 km
- Complete ACI coverage
- 30,831 parts · 64.5% of processed parts
- Partial ACI coverage
- 130 parts · 0.3% of processed parts
- No available ACI output
- 16,876 parts · 35.3% of processed parts
Compared with the fixed Donegal reference
55.5% of its 30,441 complete sections; 53.9% of its 2,735.066 km represented length.
Minimum comparison met; preferred comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (16,905 of 16,905).
- Road-class speed assumption: 86.4% of retained sections (14,602 of 16,905).
- Surface information not recorded: 87.0% of retained sections (14,702 of 16,905).
- Road-class traffic proxy: 100.0% of retained sections (16,905 of 16,905).
- Typical scenario assumptions: 100.0% of retained sections (16,905 of 16,905).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 16,876 mapped parts, containing 16,876 sections.
- Partially available output: 130 mapped parts, containing 394 sections.
- A section does not meet trace requirements: 13,380 mapped parts, containing 19,370 sections.
- A required primary comparison is unavailable: 6,082 mapped parts, containing 15,140 sections.
Westmeath7,138complete sections646.505 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 17,445
- Processed parts
- 17,445 · 100% of eligible parts
- Wholly qualifying parts
- 4,174 · 23.9% of processed parts
- Complete retained sections
- 7,138 · 646.505 km
- Complete ACI coverage
- 13,372 parts · 76.7% of processed parts
- Partial ACI coverage
- 61 parts · 0.3% of processed parts
- No available ACI output
- 4,012 parts · 23.0% of processed parts
Compared with the fixed Donegal reference
23.4% of its 30,441 complete sections; 23.6% of its 2,735.066 km represented length.
Full-inventory exception — absolute comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (7,138 of 7,138).
- Road-class speed assumption: 81.0% of retained sections (5,782 of 7,138).
- Surface information not recorded: 60.3% of retained sections (4,304 of 7,138).
- Road-class traffic proxy: 100.0% of retained sections (7,138 of 7,138).
- Typical scenario assumptions: 100.0% of retained sections (7,138 of 7,138).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 4,012 mapped parts, containing 4,012 sections.
- Partially available output: 61 mapped parts, containing 263 sections.
- A section does not meet trace requirements: 4,889 mapped parts, containing 10,907 sections.
- A required primary comparison is unavailable: 4,309 mapped parts, containing 16,808 sections.
Wexford24,019complete sections2,111.844 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 61,935
- Processed parts
- 61,935 · 100% of eligible parts
- Wholly qualifying parts
- 16,072 · 25.9% of processed parts
- Complete retained sections
- 24,019 · 2,111.844 km
- Complete ACI coverage
- 44,015 parts · 71.1% of processed parts
- Partial ACI coverage
- 161 parts · 0.3% of processed parts
- No available ACI output
- 17,759 parts · 28.7% of processed parts
Compared with the fixed Donegal reference
78.9% of its 30,441 complete sections; 77.2% of its 2,735.066 km represented length.
Preferred comparison met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (24,019 of 24,019).
- Road-class speed assumption: 40.9% of retained sections (9,821 of 24,019).
- Surface information not recorded: 82.6% of retained sections (19,828 of 24,019).
- Road-class traffic proxy: 100.0% of retained sections (24,019 of 24,019).
- Typical scenario assumptions: 100.0% of retained sections (24,019 of 24,019).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 17,759 mapped parts, containing 17,759 sections.
- Partially available output: 161 mapped parts, containing 543 sections.
- A section does not meet trace requirements: 19,256 mapped parts, containing 28,528 sections.
- A required primary comparison is unavailable: 8,687 mapped parts, containing 21,437 sections.
Wicklow17,087complete sections1,466.836 kmrepresented length
Processing and qualification
- Eligible mapped parts
- 50,226
- Processed parts
- 50,226 · 100% of eligible parts
- Wholly qualifying parts
- 12,093 · 24.1% of processed parts
- Complete retained sections
- 17,087 · 1,466.836 km
- Complete ACI coverage
- 32,083 parts · 63.9% of processed parts
- Partial ACI coverage
- 136 parts · 0.3% of processed parts
- No available ACI output
- 18,007 parts · 35.9% of processed parts
Compared with the fixed Donegal reference
56.1% of its 30,441 complete sections; 53.6% of its 2,735.066 km represented length.
Minimum comparison met; preferred comparison not met. This comparison measures the amount of retained data, not road safety or model accuracy.
Inputs and assumptions
- At least one documented fallback: 100.0% of retained sections (17,087 of 17,087).
- Road-class speed assumption: 74.9% of retained sections (12,802 of 17,087).
- Surface information not recorded: 61.4% of retained sections (10,488 of 17,087).
- Road-class traffic proxy: 100.0% of retained sections (17,087 of 17,087).
- Typical scenario assumptions: 100.0% of retained sections (17,087 of 17,087).
Fallback categories overlap and cannot be added together.
Why some parts are outside the strict collection
- No available whole-part output: 18,007 mapped parts, containing 18,007 sections.
- Partially available output: 136 mapped parts, containing 406 sections.
- A section does not meet trace requirements: 15,072 mapped parts, containing 20,285 sections.
- A required primary comparison is unavailable: 4,918 mapped parts, containing 11,461 sections.
Bars compare represented length within this collection. County coverage does not establish a representative estimate for the national road network.
Inputs and interpretation
What went into these calculations
“Complete” means the retained sections have the required numerical outputs and consistent explanations, and every section of their parent road part qualifies. It does not mean every input was measured.
- A frozen map. OpenStreetMap centreline geometry from 31 August 2026. It is not surveyed lane geometry or a reconstruction of historical road conditions. Separate carriageways contribute separate centreline length.
- A consistent scenario. The documented typical App scenario is frozen for this collection; driver behaviour and physical conditions are assumptions rather than observations.
- Traffic assumptions: 100% of retained sections. Road-class traffic proxies are used instead of measured traffic exposure.
- Speed assumptions: 73.5% of retained sections. 368,827 sections use the documented road-class speed fallback.
- Surface not recorded: 73.5% of retained sections. 368,977 sections lack recorded surface information in the source.
Fallback categories overlap and must not be added together. Model 2.0.0 remains the public App default; Model 3.2.0 remains a controlled preview with insufficient empirical evidence.
How this collection was selected, calculated and released
One clearly defined population
The calculation pool contained 1,419,158 distinct mapped road parts and 2,249,357 sections. The whole-parent completeness checks retained 318,898 parts and all 501,961 of their qualifying sections. Roads were not selected for an attractive ACI. Every eligible part in the frozen 26-county inventory was processed; this report uses one verified run per county, never duplicate reproduction runs or earlier sample copies. Requiring complete supporting outputs can exclude straight or gently curving geometry without a curve/friction comparison, so this filter affects the distribution.
| Reason | Road parts | Sections |
|---|---|---|
| No native whole-part output | 519,755 | 519,756 |
| Part not fully covered | 4,109 | 14,034 |
| Part contains a section that does not qualify | 372,053 | 612,158 |
| Part contains an incomplete primary output | 204,343 | 601,448 |
Each excluded part appears in its first applicable category once. No missing output is substituted with zero; this report does not give a competing average for excluded roads.
Weighting and disclosure
The average is the sum of section ACI multiplied by section length, divided by total represented length. Percentiles use the first sorted output whose cumulative section length reaches the stated proportion. Anonymous extrema come from this same collection. Road-class statistics are omitted under small-cell and complementary disclosure protection; county outputs are not ranked.
Source and publication
© OpenStreetMap contributors, ODbL 1.0. The Geofabrik snapshot and county-union study boundary use the same frozen source. This descriptive collection uses neither RSA collision records nor measured TII exposure.
Permission to report anonymous extrema was added after the original calculations. Public provisional permission is a separate, later owner decision; it does not rewrite the sampling protocols, approve missing reviews or promote the model.
Explore the method and evidence
Read how the index is calculated, download the same aggregate used here, or inspect the independent-review requirements and further research.