| Comments: | This CMF was obtained from Table 3.13 for “rear ends” crashes from the unsignalized set (p. 83). The years of data were obtained from Table 10.2 (p. 161). The sample size for the treatment group (total) was 156 crashes. According to the executive summary, all the superstreet sites have a rural area type (p. iv). The minimum and maximum major roadway AADTs were obtained from Table 10.4 (p. 163), and the minimum and maximum minor roadway AADTs were obtained from Table 10.5 (p. 164). The number of legs of intersections was obtained from Table 10.3 (p. 162). The after periods of some of the sites were rather short (i.e., < 1 yr). See Table 10.2 (p. 161). The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development. |
[View score details]