Immediate dividends: Within first 48 hours, ITD’s new cable rail
improves I-15 safety
A newly installed cable rail on a heavily traveled section of Interstate 15 in southeast Idaho just south of Inkom is already paying dividends, just days after it was installed to improve safety.
“ITD's southeast Idaho District 5 office strongly believed that this project could save many lives, and within the first 48 hours of completion, it had already proved its effectiveness,” District Operations Manager Steve Gertonson said.
The section of highway carries almost 16,000 vehicles per day. It has a narrow, 25-foot median separating the northbound and southbound lanes of travel, and a history of errant vehicles crossing through the median and entering the opposing lanes of traffic. There have been 58 crashes in this stretch of I-15 in the last five years.
The cable-rail system is designed to keep errant vehicles from continuing across the median and either hitting the guardrail from behind or entering the lanes of traffic moving at freeway speeds in the opposite direction. Both options are extremely hazardous.
The cable-rail installation was completed at 5 p.m. Wednesday (Dec. 7). Just before 5 p.m. on Friday (Dec. 9), the cable rail had its first major test, and passed with flying colors.
The new cable-rail system was impacted by an errant vehicle on the northbound freeway less than two miles from Inkom, and the posts collapsed while the cable remained intact (as designed). The motorist was able to drive away from this incident.
ITD’s District 5 (southeast Idaho area) requested this cable-rail project as a high-priority safety improvement initiative funded by savings that came from changes to the agency’s equipment-purchasing policy.
"Cable rail was a good choice for our Inkom project because that stretch features narrow median and sharper curves that lessen the recovery zone; meaning when vehicles depart they can cross through the median and end up in the opposite lane. Cable rail is designed to prevent that, and we feel like it did a great job the other day," explained southeast Idaho District Engineer Ed Bala.
Because this is the first cable-rail project in D5, the district does not have spare parts or tensioning tools on hand to repair the damage. However, ITD District 4 (south-central Idaho) volunteered spare parts, tools, and crew members to come to D5 Dec. 13 to assist in completing repairs. Earlier this year, District 4 installed the state’s first median cable tension system on a stretch between Utah and the I-84/I-86 junction known as Sweetzer Summit.
About three weeks after it was installed, it too was "tested" by a motorist, and performed perfectly.
Published 12-16-16