Knowledge Resources

In 2000, the Arkansas State Highway and Transportation Department (AHTD) began the Interstate Rehabilitation Project, a major construction effort including the rebuilding of 60% of Arkansas’ total Interstate miles. In response to the increase in number of work zone sites statewide, AHTD implemented a safety program, including five highway projects, in an attempt to minimize work zone incidents. This report covers two work zones that were equipped with two different types of Automated Work Zone Information Systems (AWIS) in an attempt to mitigate traffic congestion and automobile incidents at the work zone site.

Both systems were provided by a contractor and each work zone contractor was required to select from a choice of two vendor AWIS systems. Both systems utilize traffic sensors and changeable message signs (CMS) that are equipped to communicate with a central controller via radio (FCC or FHWA band). The CMS were automated to display one of the various preset messages available. The display corresponded to the scenario monitored by the traffic sensors.

The costs given are the winning bids submitted by the contractors. The cost figures are divided into two separate costs, a daily fee and an HAR fee. Daily costs include relocation costs associated with the job setup, the rental of hardware equipment, staff to maintain the system and traffic information displayed on a website. The website is maintained by the contractor and provides users with the information given on the CMS and HAR, as well as, real-time backup location and severity. The flat rate for the HAR systems includes rental of hardware and equipment maintenance for the duration of the project. The cost was divided in the event of downtime; the contractor may be penalized depending upon which equipment is not functional. No equipment was purchased in the given costs.

The first site was a 6.3 mile segment of I-40 located in Lonoke County. This segment of roadway is considered rural and has an average daily traffic volume of 36,350 vehicles, with 43 percent of traffic being trucks. The AWIS deployed at this work zone site included: a central system controller, two highway advisory radios (HAR), five traffic radar sensors measuring vehicle speed, five CMS and two supplemental speed stations. The system provided real-time traffic, delay and diversion advisories to travelers through CMS and pager alerts to selected personnel. The system communicated with the HAR via landline telephone. The contract bid for 350 days at $750 per day plus $60,000 for the HAR systems, totaled $322,500. The project was let to contract in May 2000 and completed in November 2001.

The second site was an 8.6 mile segment of I-40 located in Pulaski County or urban North Little Rock. This segment has a daily traffic volume of 44,000 vehicles, with 35 percent truck traffic. The AWIS deployed at this work zone site included: a central system controller, a host computer in the engineer’s office, two changeable message signs, queue detection sensors and five highway advisory radio systems which communicated with the AWIS by landline telephone. Traffic sensors provided delay information related to construction and communicated this information to the CMS. The CMS displayed the appropriate message to the motorists. These messages included delay information and/or warnings for speed reduction depending upon the speed detected by the traffic sensors. The contract bid for 1,000 days at $390 per day plus $100,000 for the HAR systems, totaled $490,000. The project was let to contract in January 2001 and was completed in September 2003.

See also: Fact Sheet 9 - Arkansas Uses Public Outreach to Pave The Way During Interstate Rehabilitation