10.2.1 Rate of RBTs
The Australian Capital Territory RBT data spans July 2004 to October 2012 (see the lower data series in Figure 26). During this period the minimum monthly rate of RBTs conducted was 226 (April 2005);
the maximum rate of RBTs was 16,762 (April 2006). The mean rate of RBTs conducted across the period was 7,013 (SD 3,277). For the first six months of the series the average monthly rate of RBTs conducted in the Australian Capital Territory was 4,534 (SD 3,488); this increased to 6,631 (SD 2,430) for the last six month period. The trend line suggests that there was one significant deviation across the series in the monthly RBT rates. The first section is between July 2004 and June 2006;
the MPC for this section was 5.65 (2.27 to 9.14; p<0.001). The second section is between June 2006 and October 2012; the MPC for this section was −0.11 (−0.65 to 0.44; p=0.695). This suggests that the estimated monthly rate of RBTs significantly increases by 5.65 per cent between two consecutive months until June 2006. After June 2006, the MPC is non-significant and does not significantly differ from a flat trend; that is an MPC of 0 between any two consecutive months.
Figure 26. Australian Capital Territory: Monthly rate of RBTs. The lower series represents absolute numbers the top series represents proportion per 1,000 licensed drivers
10.2.2 Rate of RBTs per 1,000 licensed drivers
The upper data series of Figure 26 represents the RBT rate after accounting for the population of licensed drivers in the Australian Capital Territory. The data spans July 2004 to October 2012. The following RBT information is relative to the estimated number of licensed drivers. Data is presented per 1,000 licensed drivers. During this period the minimum monthly rate of RBTs conducted was 0.86 (April 2005); the maximum rate of RBTs was 62.53 (April 2006). The mean rate of RBTs conducted across the period was 24.61 (SD 11.63). For the first six months of the series the average monthly rate of RBTs conducted in South Australia was 17.42 (SD 13.35); this increased to 21.22 (SD 7.82) for the last six month period. The trend line suggests that there was one significant deviation across the series in the monthly RBT rates per 1,000 licensed drivers. The first section is between July 2004 and June 2006; the MPC for this section was 5.50 (2.12 to 8.98; p=0.001). The second section is between June 2006 and October 2012; the MPC for this section was −0.32 (−0.85 to 0.23;
p=0.246). This suggests that the estimated monthly rate of RBTs, after adjusting for the number of licensed drivers, significantly increases by 5.50 per cent between two consecutive months until June 2006. After June 2006, the MPC is non-significant and does not significantly differ from a flat trend;
that is an MPC of 0 between any two consecutive months.
0
No. of RBTs (solid) per 1,000 LDs
0
10.3 Monthly alcohol-related traffic crash rates: Absolute numbers and per 100,000 licensed drivers
10.3.1 Rate of ARTCs
The Australian Capital Territory ARTC data spans January 2000 to October 2012 (see the lower data series in Figure 27). During this period the minimum monthly rate of ARTCs reported was one (at multiple months: May 2000, January 2001, January 2010 and October 2011); the maximum rate of ARTCs reported was ten (June 2000). The mean number of ARTCs reported across the period was five (SD 2). For the first six months of the series the average monthly rate of ARTCs reported in the Australian Capital Territory was five (SD 3); this was four (SD 2) for the last six month period. The trend line suggests that there was no significant deviation across the series in the monthly ARTC rates. The MPC for the series was −0.09 (−0.27 to 0.08; p=0.298). As the MPC is not significant this suggests that the estimated monthly ARTC rate does not significantly differ from a flat trend; that
is an MPC of 0 between any two consecutive months.
Figure 27. Australian Capital Territory: Monthly rate of ARTCs. The lower series represents absolute numbers the top series represents proportion per 100,000 licensed drivers
10.3.2 Rate of ARTCs per 100,000 licensed drivers
The upper data series of Figure 27 represents the ARTC rate after accounting for the population of licensed drivers in the Australian Capital Territory. The data spans January 2000 to October 2010.
The following ARTC information is relative to the estimated number of licensed drivers. Data is presented per 100,000 licensed drivers. During this period the minimum monthly rate of ARTCs reported was 0.33 (October 2011); the maximum rate of ARTCs was 4.26 (June 2000). The mean rate of ARTCs reported across the period was 1.79 (SD 0.76). For the first six months of the series the average monthly rate of ARTCs reported in the Australian Capital Territory was 2.07 (SD 1.42);
this decreased to 1.23 (SD 0.56) for the last six month period. The trend line suggests that there
0
No. of ARTCs (solid) per 100,000 LDs
0
drivers. The MPC for the series was −0.29 (−0.46 to −0.11; p=0.001). This suggests that the estimated monthly ARTC rate, after adjusting for the number of licensed drivers, significantly decreases by 0.29 per cent between any two consecutive months.
10.4 Monthly rate of RBTs per 1,000 licensed drivers and monthly rate of ARTCs per 100,000 licensed drivers
Figure 28. Australian Capital Territory: Monthly rate of ARTCs and monthly rate of RBTs proportional to the annual rate of licensed drivers
Figure 28 highlights there is one significant deviation in the series for the monthly RBT rate in the Australian Capital Territory between July 2004 and October 2012. Between July 2004 and June 2006 the estimated monthly RBT trend significantly increased by 5.50 per cent between two consecutive months. For the six months commencing July 2004 the estimated monthly rate of RBTs was 17.42 (SD 13.35); by the end of the segment (June 2006) the estimated monthly rate of RBTs for the last six months was 35.42 (SD 14.67). In the two year period the estimated monthly rate of RBTs had increased by 35.42 per 1,000 licensed drivers. Following June 2006 the monthly RBT rate was flat.
The mean monthly RBT rate for this period was 26.24 (SD 10.25) per 1,000 licensed drivers.
Annually, this translates to approximately 314 RBTs per 1,000 licensed drivers which is equivalent to an RBT to licensed driver ratio of 0.3:1.
There is no significant deviation in the series for the monthly ARTC rate. The estimated monthly ARTC trend significantly decreases by 0.29 per cent between two consecutive months. For the six months commencing January 2000 the estimated monthly rate of ARTCs 2.14 (SD 1.57); by the end of the series (October 2010) the estimated monthly rate of ARTCs for the last six months was 1.12 (SD 0.35). Across the series the estimated monthly rate of ARTCs dropped by 1.02 per 100,000
10.5 Conclusion
The rate of ARTCs in the Australia Capital Territory has fallen since January 2000 regardless of the increase in RBTs by police between July 2004 and June 2006 and the subsequent plateau in RBTs rates. The mean RBT rate conducted across the period was 24.61 (SD 11.63) per 1,000 licensed drivers. The RBT trend line suggests one significant deviation across the series, the first section between July 2004 and June 2006; shows increases until June 2006. After June 2006, the trend is flat. The ARTC data spans January 2000 to October 2010. The mean rate of ARTCs reported across the period was 1.79 (SD 0.76). The trend line suggests that there was no significant deviation across the series in the monthly ARTC rates per 100,000 licensed drivers, the monthly ARTC rate significantly decreases across the series. In summary, it appears the RBT trend increases between July 2004 and June 2006 and is then flat to the end of the series. ARTC rates have declined since January 2000 regardless of the increase and plateau in RBT rates.