2018 Issue

56 Abstract A crash analysis of a major arterial roadway in a suburb of Salt Lake City, Utah revealed that safety improve- ments implemented during a three- year construction project reduced crashes by 40 percent per year and reduced the severity of crashes overall. Five Keywords: Safety improvements, Crash severity, Intersection improve- ments, Arterial roadway, Access control Crash analyses are often completed prior to the design and construction of safety improvement projects to help identify the most appropriate safety improvements based on the crash history. The effects of those safety improvements are rarely quantified by transportation engineers following the completion of construction. However, Sandy City, a suburb of Salt Lake City, Utah, wanted to forgo the usual and instead conduct a before and after crash analysis to better understand the return on investment of the safety improvements that they constructed along one of the City’s major arterial roadways, 1300 East (See Figure 1). The findings of the study showed that the addition of raised medians, median barriers, right turn lanes, street lighting, pedestrian access ramps, signs with improved retroreflectivity, bicycle lanes with bicycle safe catch basin grates, and more visible signals, among other improvements, reduced the severity and number of crashes by 40 percent per year along the 5-mile corridor. Calculating the Value of Arterial Safety Improvements Before and After Study Shows Safety Improvements Reduced Crashes by 40 Percent Authors: Kelly Harris, PE, PTOE; Ryan Nuesmeyer , PE; and Kelly Hanks Project Engineering Consultants 986 West 9000 South, West Jordan, UT 84088 Office: 801.495.4240 rnuesmeyer@pec.us.com Ryan Kump, PE Sandy City Transportation Engineer 8775 South 700 West, Sandy, Utah 84070 Office 801.568.2962 Cell 801.598.6296 rkump@sandy.utah.gov Figure 1 shows the construction improvements along part of the 1300 East Corridor. Defining the Need for Safety Improvements In 2006, various sections on the corridor had an average annual daily traffic (AADT) volume ranging from23,000 to 42,000, with speed limits ranging from40 to 45 miles per hour. Between 2006 and 2009, 601 crashes were recorded by the Utah Department of Transportation (UDOT) along the corridor—an average of 200 crashes per year. Angle and front-to-rear crashes were the twomost prevalent types of crashes on the corridor. According to values set by UDOT’s Division of Traffic and Safety using the KABCO injury scale (devel- oped by theNational Safety Council), the estimated societal and economic cost to motorists involved in these crashes during the three year periodwas $51.3million. The combination of large traffic volumes, vehicular speed, roadway geometrics, and other roadway characteristics resulted in a significant number of crashes and a need for safety improvements. Details of the Safety Improvements In response to the crash history, Sandy City began a three-year, $26 million construction project in 2009 to im- prove safety and reduce crashes along the major arterial. The construction projects were divided into three seg- ments along 1300 East: Creek Road to 8600 South, 8600 South to 9400 South, and 9400 South to 11000 South (See Figure 2). Raised medians were built in each of the three segments. Seven signalized intersections were recon- structed along the corridor; right-turn lanes were added at most intersec- tions. Continuous street lighting was added. Nearly 150 pedestrian access ramps were improved to comply with the American Disabilities Act (ADA) standards at every intersection and cross street along the corridor. Most of the corridor was widened by 12 feet on average. A vertical curve was reduced in one section to improve sight dis- tance. A grade-separated equestrian tunnel was built at a park crossing. Road signs, pavement marking tape, and thermoplastic messages were replaced or new ones were added to meet the Manual on Uniform Traffic Control Devices (MUTCD) guidelines. Continuous sidewalks were added throughout the corridor for better pe- destrian connectivity. Storm drainage improvements were also completed along the corridor.