2018 Issue

59 percent to 13 crashes, the signalized intersection became an area of concern post construction due to one of the five angle crashes being classified as severe. Section 3D Segment The Section 3D Segment had 29 crashes in the three years pre-construction. A landscaped median was constructed in this segment, as well as an equestrian tunnel. In the three years post-construction, Section 3D had 11 crashes, with one of the five angle crashes being severe. Due to this se- vere crash and other similar crashes, this section became an area of concern despite the number of crashes decreasing by 62 percent. Crash Severity Analysis As part of the crash analysis, a crash severity analysis of the corridor was conducted to determine if crash severity of the pre-construction crashes compared to the post-con- struction crashes decreased. Crash severity was analyzed by segments and by the corridor as a whole. The severity of crashes was evaluated using the crash analysis method identified in UDOT’s Operational Safety Report Manual 1 . According to the manual, crashes are ranked by level ac- cording to severity, similar to the KABCO scale (See Table 1). Level 5 crashes involve a fatal injury. Level 4 crashes involve incapacitating injuries (i.e., at least one individual involved in the crash is taken to a hospital by ambulance). Level 5 and level 4 crashes are considered severe. Level 3 crashes involve non-incapacitating injuries. Level 2 crashes may have possible injuries. Level 1 crashes have no injuries and involve property damage only. Table 1 shows the severity level of crashes and the societal costs of each level of crash 2 . Using this crash analysis method, 17 severe crashes oc- curred within the study area during the pre-construction period. Two locations, Forbush Lane and 10600 South, had more than one severe crash, all of which were angle crash- es. The other severe crashes were of various manner of collision and occurred at different locations throughout the corridor. In the three years after construction, 14 severe crashes occurred in the study area. At 10600 South, severe crashes decreased from four during the three years before construction to zero during the three years after construction. Six areas that had not previously had severe crashes had at least one severe crash during the three year period post construction; a total of seven severe crashes occurred at these new locations. The number of severe crashes at Forbush Lane remained the same. The number of severe crashes at 8600 South increased by one. Averaging the reductions of each level of severity, the corri- dor experienced an average reduction of 41 percent. Each severity level was decreased as indicated (See Figure 5): • Severity level 5 crashes were reduced 100 percent from one pre-construction crash to zero post con- struction crashes (due to the limited quantity of level 5 crashes, the crash reductions of this type were deemed statistically insignificant); • Severity level 4 crashes were reduced 11 percent, from 16 crashes pre-construction to 14 crashes post con- struction; • Severity level 3 crashes were reduced 6 percent overall, from 67 pre-construction crashes to 63 post construction crashes; • Severity level 2 crashes were reduced from 136 crashes pre-construction to 76 crashes post construction, a 44 percent reduction; and • Severity level 1 crashes were reduced by 45 percent, from 381 crashes pre-construction to 210 crashes post construction. Figure 5 shows the average number of severe crashes along 1300 East in the three years prior to construction and the three years after construction. Societal Cost Savings The UDOT Division of Traffic and Safety periodically evalu- ates crash costs using the KABCO injury scale (developed by the National Safety Council) and has assigned a dol- lar amount to the severity of a crash (See Table 1). Dollar amounts are assigned for productivity losses, property damage, medical costs, rehabilitation costs, congestion costs, legal and court costs, emergency services such as medical, police, and fire, insurance administration costs, and the costs to employers. The dollar amount also includes