Search Results

Non-recurring incidents on our nation's freeways is estimated to cost over $60 billion a year. The challenge is to develop an effective methodology to electronically identify these incidents quickly in order to manage the freeway operation and restore the facility to its optimum operating level in the minimum time. Single vehicle loop detectors have traditionally been used to measure occupancy on the freeway segments as a means of determining when incidents have occurred. Most incident detection algorithms using the traditional occupancy parameter have either taken too long to report an incident or they have given an excessive number of false alarms. Trap travel time obtained from two loops in each lane is shown in this paper to have the promise of much faster detection of the incidents with a lower false alarm rate.

The rapid development and technological changes inherent in IVHS projects can make following standard State bidding practices ineffective. The Arizona Department of Transportation's (ADOT) Freeway Management System project has recently used several non-traditional contracting concepts to ensure delivery of its Advanced Traffic Management System. These contracting procedures include a two-step bidding process, requisitioning from existing statewide contracts, and total life cycle cost bidding for electronic variable message signs. Two-step procedures, statewide procurement contracts, and total life cycle cost bidding procedures provide ADOT with unique concepts to purchase equipment in an effort to obtain the highest quality for a reasonable price. The innovative processes have resulted in 7% to 30% lower overall cost and greater probability of project success. As high technology items are dealt with by public agencies, it is necessary to be innovative in the ways we procure systems.

The Arizona Department of Transportation is implementing an Advanced Traffic Management System Freeway Management System (FMS) for 99 miles of their freeway network. The first project containing 29 miles has been under construction since March 1993. The system will include a vehicle detection system to electronically identify incidents. Management of the incidents will be accomplished with Model 179 ramp metering controllers and fiber optic variable message signs. The field equipment will be interconnected with a fiber optic communications system to a RISC, UNIX based computer system. A new 18,000 square foot control center will house the central equipment and operators. Multiple procurement contracts for the computer equipment and variable message signs have been executed. Kimley-Horn and Associates will serve as the system manager to integrate and test the fust phase of the ATMS which is to be operational in 1995.