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Safety Analysis

Safety conditions along the I-25 Corridor and US 85 Corridor were quantified by examining the most recent crash records (covering the calendar years 1995, 1996, and 1997). Total numbers of crashes during this three-year period are shown in the figure below. The largest crash frequencies (150 during the three-year period) on I-25 occurred between Schweiger (milepost 191) and Surrey Ridge (milepost 190) and between Happy Canyon Road (milepost 187) and Meadows/Founders (milepost 184). The largest crash frequency (48 during the three years) along US 85 occurred between Titan Road (milepost 196) and Louviers Avenue (milepost 194).

While the frequency of crashes within a roadway segment is important, an additional measure, the crash rate, is needed in evaluating safety. A crash rate is defined by the number of total crashes per million vehicle miles of travel and allows a comparison of different roadways. Rates can be compared to the statewide average for a given roadway type. The crash rate for each segment as compared to the 1996 state average crash rate is shown in the following table. Clicking on a segment of the safety analysis map displays the frequency of crashes and the type of crashes.
 

I-25 Crash Rates
(crashes per million vehicle miles traveled)
A = Federal Aid Rural Interstate     B = Federal Aid Urban Interstate
Segment Class Crash Rate 1996 State Average
Segment 1 A 1.13 0.90
Segment 2 A 1.51 0.90
Segment 3 A 1.28 0.90
Segment 4 A 1.10 0.90
Segment 5 A 1.05 0.90
Segment 6 B 0.87 1.92
Segment 7 B 0.98 1.92
Segment 8 B 1.81 1.92
Segment 9 A 0.72 1.90
Bold Numbers indicate segments where the crash rate is higher than the state average


US 85 Crash Rates
(crashes per million vehicle miles traveled)
C = Federal Aid Primary Urban Interstate     D = Federal Aid Primary Rural Interstate
Segment Class Crash Rate 1996 State Average
Segment 10 C 1.02 3.17
Segment 11 D 1.15 1.22
Segment 12 D 0.29 1.22
Segment 13 D 1.20 1.22
Segment 14 D 1.83 1.22
Segment 15 D 0.62 1.22
Segment 16 D 1.18 1.22
Segment 17 C 0.99 3.17
Segment 18 C 1.69 3.17
Bold Numbers indicate segments where the crash rate is higher than the state average

Crashes are classified into the following types:

  • Animal – A vehicle colliding with a wild or domestic animal
  • Approach Turn – A broadside crash involving a turning vehicle
  • Bicycle – A vehicle colliding with a bicyclist
  • Broadside – The front of a vehicle collides with the side of another vehicle
  • Fixed Object – A collision involving a vehicle and a non-moving object (such as a median barrier, delineator, guard rail, bridge rail, curb, tree, sign, parked vehicle, etc.)
  • Head-On – The front of two vehicles collide
  • Other – A miscellaneous (unidentified) crash type
  • Other Non-Collision – A miscellaneous crash category in which no collision occurs
  • Overturning – A crash resulting in a vehicle rolling or turning over
  • Rear-End – The front of a vehicle collides with the rear of another vehicle
  • Sideswipe – Two vehicles traveling the same direction crash sides
  • Sideswipe Opposing Direction – Two vehicles traveling in opposite directions crash sides
  • Unknown – An unknown type of collision

Types and patterns of crashes within each roadway segment (i.e., between interchanges or intersections) will be analyzed to determine possible contributing factors. Transportation improvements addressing the likely cause of specific crash patterns will be investigated. For example, if a specific location experienced a high frequency of fixed object accidents, options for relocating the fixed object would be identified.

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Last Updated: 07.07.2008 04:13 PM

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