Table 1

Annual road traffic collision rates by severity rates for intervention and control sites over time

Site/severity2 years pre-implementation1 year pre-implementationIntervention implementation1 year post-implementation3 years post-implementation
20142015201620172019
Intervention site
 Slight injury80 (−7%; p=0.64)86 (Ref)76 (−12%; p=0.43)76 (−12%; p=0.43)72 (−16%; p=0.27)
 Serious injury/fatal4 (+100%; p=0.42)2 (Ref)3 (+50%; p=0.66)9 (+350%; p=0.05)3 (+50%; p=0.66)
 Overall84 (−5%; p=0.76)88 (Ref)79 (−10%; p=0.47)85 (−3%; p=0.82)75 (−15%; p=0.31)
Control site (city centre)
 Slight injury100 (+2%; p=0.89)98 (Ref)101 (+3%; p=0.83)90 (−8%; p=0.56)106 (+8%; p=0.58)
 Serious injury/fatal6 (+50%; p=0.53)4 (Ref)7 (+75%; p=0.37)12 (+200%; p=0.06)8 (+100%; p=0.26)
 Overall106 (+4%; p=0.78)102 (Ref)108 (+6%; p=0.68)102 (0%; p=1.00)114 (+12%; p=0.41)
Control site (metropolitan area)
 Slight injury1078 (+6%; p=0.19)1018 (Ref)1034 (+2%; p=0.72)974 (−4%; p=0.32)939 (−8%; p=0.07)
 Serious injury/fatal79 (−11%; p=0.44)89 (Ref)102 (+15%; p=0.35)97 (+9%; p=0.56)67 (−25%; p=0.08)
 Overall1157 (+5%; p=0.29)1107 (Ref)1136 (+3%; p=0.54)1071 (−3%; p=0.44)1006 (−9%; p=0.03)
Matched control
 Slight injury26 (0%; p=1.00)26 (Ref)23 (−12%; p=0.67)25 (−4%; p=0.89)23 (−12%; p=0.67)
 Serious injury/fatal2 (+100%; p=0.57)1 (Ref)1 (0%; p=1.00)3 (+200%; p=0.34)1 (0%; p=1.00)
 Overall28 (+4%; p=0.89)27 (Ref)24 (−11%; p=0.68)28 (+4%; p=0.89)24 (−11%; p=0.68)
  • Fatal injury is one which causes death less than 30 days after the accident. Serious injury is one which does not cause death but serious injury such as needing to be detained in hospital as an inpatient, fractures, concussion, internal injuries. Slight injury is any injury which is neither ‘fatal’ nor ‘serious’, for example, a sprain, bruise or cut which is not judged to be severe, or slight shock requiring roadside attention.

  • Ref, reference case.