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Table 2 Summary of evaluation results for treatments on road sections: efficiency indices and their 95 % confidence intervals
From: The evaluation of safety efficiency of non-urban infrastructure improvements; a case-study
Type of infrastructure improvement (#) | Injury accidents | Severe accidents | Total accidents |
Upgrading a single-carriageway to a dual-carriageway road section (2) | −32 % [−48 %; −11 %] | Reduction trend, ns | −31 % [−41 %; −19 %] |
Building a median on a road section crossing an urban area (2) | No change | -- | −53 % [−66 %; −37 %] |
Barrier installation - building a rigid median, on a single-carriageway road (4) | −50 % [−68 %; −24 %] | Reduction trend, ns | −23 % [−40 %; −2 %] |
A combined treatment: barriers, road marking/signing, on a single-carriageway road (4) | Increasing trend, ns | -- | −13 % [−27 %; +3 %]* |
A combined treatment: barriers, road marking/signing, on a dual-carriageway road (3) | No change | No change | −14 % [−22 %; −6 %] |
A combined treatment: resurfacing, road marking, barriers' treatment, on a single-carriageway road (6) | −16 % [−29 %; −1 %] | No change | −20 % [−28 %; −11 %] |
A combined treatment: resurfacing, road marking, barriers' treatment, on a dual-carriageway road (6) | −23 % [−30 %; −16 %] | No change | No change |
A combined treatment: barriers, resurfacing, shoulders, on a single-carriageway road (5) | −12 % [−23 %; −0 %] | Increasing trend, ns | −19 % [−25 %; −13 %] |
A combined treatment: signs, pavement, shoulders, on a single-carriageway road (1) | Reduction trend, ns | Reduction trend, ns | Reduction trend, ns |
A combined treatment: resurfacing, crash cushions' installation, barriers' treatment, on a dual-carriageway road (1) | No change | No change | −17 % [−24 %; −11 %] |
Pavement treatments, including road marking, raised markers, on a single-carriageway road (1) | No change | Reduction trend, ns | −23 % [−38 %; −5 %] |