Study Shows Crashes Reduced by 40 Percent with New Safety Improvements
Apr 07, 2016 04:11PM
● By Stacy Nielsen
By Stacy Nielsen | [email protected]
Sandy - Crash analyses are often completed prior to the design and construction of safety improvement projects. However, the effects of the safety improvements are not always quantified after their completion. Sandy City officials wanted to conduct a before-and-after crash analysis to better understand the return of investment of the safety improvements along one of its major arterial road: 1300 East. The data was analyzed by Project Engineering Consultants Ltd. and indicates the safety improvements made reduced the severity and number of crashes by 40 percent along the 5-mile stretch of road.
“The results show a significant increase in public safety—always one of our top concerns,” Sandy City Communications Director Nicole Martin said.
Between 2006 and 2009, 601 crashes were recorded by the Utah Department of Transportation, averaging 200 crashes per year. In 2009, Sandy City began a three-year safety construction project estimating $26 million in efforts to improve safety and reduce crashes along the roadway. The projects were divided into three segments along 1300 East: Creek Road to 8600 South, 8600 South to 9400 South, and 9400 South to 11000 South.
The improvements included raised medians, median barriers, right-turn lanes, street lighting, pedestrian access ramps improved to comply with the American Disabilities Act, signs with improved reflectivity, bicycle lanes with safe catch basin grates, more visible signals and other improvements. Most of the corridor was also widened by an average of 12 feet.
For the purpose of the study, severe crashes were identified as those involving a fatality or a person being taken to a hospital by way of ambulance. If a high number of less severe crashes were reported in an area, those crashes were analyzed to determine whether a pattern of multiple crashes of a similar collision occurred. Additionally, the segments were further divided into smaller sections and analyzed individually to determine if certain sections had more severe crashes or more crash clusters than others.
The study identified eight areas of concern, four of which were no longer concerning after the construction. Even though crashes were reduced at the remaining four locations, they stayed areas of concern, including Forbush Lane, 8600 South, 9400 South and Sego Lily.
In the three years following improvements, 37 crashes were recorded at the Forbush Lane intersection and since four of the 25 post-construction angle crashes at this intersection were severe. At the 8600 South intersection, 19 crashes occurred, and two of the 14 angle crashes were severe; the other 5 crashes were front-to-rear. Crashes at the 9400 South intersection actually increased by 14 percent after the safety improvements were made, going from a recorded 36 crashes prior to the construction to 41. Meanwhile, the intersection at Sego Lily Drive shows a 25 percent decrease in crashes but remains an area of concern, because of 10 severe angle crashes and that number creates a cluster.
In addition to the four areas that have remained a concern, two more areas were identified in the post-construction date. These sections include the Ridgemark Drive intersection and, on 1300 East, a segment near Sego Lily to just before 10600 South. Ridgemark Drive was identified because one of the five angled crashes was classified as severe, and 11 crashes with five being severe near 1300 East and Sego Lily. Due the severe crashes and other similar crashes, this area became a concern despite crashes decreasing by 62 percent.
Overall, the changes that Sandy made to the 1300 East Corridor were successful in improving safety. An average of 79 percent fewer crashes occurred per year, a decrease of 40 percent. The number of crashes that occurred in the areas of concern were reduced by 38 percent per year, and all crash types were also reduced. The severe crash rates decreased by an average of 41 percent per year, with the lower severity crashes showing the greatest decrease.
Sandy City leaders plan to make additional safety improvements to the corridor to reduce crashes in the new areas of concern and the areas that still remain a concern.
“By having the foresight to do a ‘before study’ to compare with after construction, we can definitively show residents these changes made a difference, that their taxpayer dollars were wisely invested and, most importantly, that road safety has been improved, potentially saving lives,” Martin said. “That’s reassurance money can’t buy.”