| Countermeasure | CRFs | ||||
| Average CRF from the county engineers’ survey (%) | CRF from the FHWA report (%) [12] | % of survey responses matching the FHWA CRFs | CRF from the surveys in the FHWA’s CRF range? (Yes/No) | ||
| Rear-end crash type | |||||
| Flatten horizontal curve | 37 | 24 - 73 | 75% | Yes | |
| Increase the number of lanes | 32.5 | 32 - 53 | 75% | Yes | |
| Improve pavement friction (grooving) | 35 | 35 - 54 | 63% | Yes | |
| Install acceleration/deceleration lanes | 64.5 | 75 | 77% | No | |
| Install channelized lane | 70.4 | 93 | 75% | No | |
| Install lane-assignment signs | 8.1 | 10 | 77% | No | |
| Improve pavement friction (overlay) | 11.4 | 12 | 70% | No | |
| Install edge-line markings | 35.3 | 45 - 50 | 67% | No | |
| Implement maintenance and bituminous overlay | 18.5 | 21 | 60% | No | |
| Head-on crash type | |||||
| Widen lane | 36.2 | 5 - 70 | 70% | Yes | |
| Widen shoulder (paved) | 41.7 | 15 - 75 | 70% | Yes | |
| Improve pavement friction (overlay) | 31.5 | 19 - 61 | 70% | Yes | |
| Install centerline rumble strips | 41.3 | 21 - 68 | 77% | Yes | |
| Widen bridge | 37 | 40 - 50 | 80% | No | |
| Flatten horizontal curve | 47.8 | 64 - 67 | 70% | No | |
| Increase the number of lanes | 36 | 38 - 53 | 77% | No | |
| Install shoulder bus lanes | 38.9 | 50 | 77% | No | |
| Install curve advance-warning signs | 24.2 | 29 | 80% | No | |
| Install delineators (general) | 58.6 | 67 | 80% | No | |
| Improve pavement friction (curve overlay) | 68 | 86 | 70% | No | |
| Improve pavement friction (resurface with deicing additives) | 21.8 | 31 | 67% | No | |
| Improve pavement friction (resurface with open-graded mix) | 71.1 | 90 | 77% | No | |
| Pave shoulder | 61.6 | 86 | 56% | No | |
| Install no-passing line | 37.7 | 40 | 77% | No | |