**5. Weibull reliability test for the deterioration of the width of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road**

The shape parameter *β* and the 95% confidence interval of *β* for the data regarding the width of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road are given in

*Quality Impairments in Flexible Road Pavements DOI: http://dx.doi.org/10.5772/intechopen.105697*

**Figure 9.** *Failed portion in Technical College Road.*

**Figure 10.** *Failed portion in Textile Mill Road.*

**Figure 11.** *Failed portion in Ogida/Upper Siluko Road.*

**Table 6**. The road is reliable and there is not enough evidence for the deterioration of the road if the shape parameter *β* is close to 1 and the 95% confidence interval of *β* contains 1.

There is enough evidence though for the deterioration of the width of the roads in Ikpoba Hill, Lucky Way, Mission, New Benin, Ogida, Ring, Sapele and Technical College since the value of *<sup>β</sup>*^ <sup>¼</sup> <sup>22</sup>*:*29 from **Table 6** is far from 1, and the approximately 95% confidence interval for *<sup>β</sup>*^½ � <sup>11</sup>*:*45, 43*:*<sup>40</sup> does not contain 1. The plot of the failure

**Figure 12.** *Failed portion in Upper Sapele Road.*

rate or hazard function, which describes the likelihood of deterioration in width during the next time increment is given in **Figure 13**.

There is a steeper increase after 225 days in the hazard function in **Figure 13**. This shows that the tendency of the width of the road to deteriorate increases after the 225th day. This is due to the value of ^*<sup>β</sup>* <sup>¼</sup> <sup>22</sup>*:*29 being far from 1, and the approximately 95% confidence interval for *<sup>β</sup>*^½ � <sup>11</sup>*:*45, 43*:*<sup>40</sup> does not contain 1. The plot of the reliability test that shows the trend of reliability (the probability of the width of the road not deteriorating at time t) with time is given in **Figure 14**. The deterioration started after the 225th day. There was a sharp rate of deterioration (decrease in the reliability status) of the width of the roads in Lucky Way, Mission Road, New Benin Road, Ogida Road, Ring Road, Sapele Road, Technical College Road and Textile Mill Road after the 225th day.
