In a ROADS & BRIDGES case study published last October, we reported that Utah DOT had recently conducted tests on portable rumble strips.
Utah DOT conducted a live test in early August 2013 on I-70 near Green River. The location featured both high average daily traffic (ADT) and a high posted speed limit of 75 mph. The temperature on test day was about 70° F, with asphalt pavement temperatures on the asphalt at 85-90° F.
After traffic control was in place, including a “Rumble Strips Ahead” temporary sign, two arrays of three strips each were placed about 50 ft apart in the same travel lane. The strips were placed on 10-ft centers.
Utah DOT engineers observed the effect of the portable rumble strip arrays on drivers, and vice versa. They saw that the arrays alerted drivers to upcoming changes in road conditions, and that most drivers reduced their speed. Engineers also saw that the arrays remained in place, with little movement.
As a follow-up, in November 2013 the Utah DOT issued Detail Sheet 11523, “Temporary Portable Rumble Strip” for use on various upcoming projects. The detail sheet addresses portable rumble strip placement, and warning-sign legends and spacing.
In the same month, Utah DOT issued a Finding in the Public Interest (FIPI) for RoadQuake 2 portable rumble strips.
A FIPI is an FHWA program. Known also as Public Interest Finding (PIF), FHWA recognizes that there are situations that require a deviation from normal policy and procedures in order to better serve the public interest. As such, while situations may exist, those situations should prove rare.
FHWA allows the issuance of a PIF “in the following areas: use of proprietary products, use of public equipment, and contract award based on a method other than competitive bidding.”
In its FIPI, Utah DOT determined that the product both reduces the chance of injury to the driving public, and reduces the risk of exposure to the workers installing the product.
The Utah DOT FIPI is effective until November 2018.