Brian Donavan (kneeling), construction foreman with Tri-Valley Landscaping of Saginaw, monitors the auger as it drills a foundation hole for the cable guardrail system on I-75 near St. Ignace. Work progressed slowly Wednesday, October 28, for the Tri-Valley crew as rocks and water hampered progress. Frequent breaks from drilling were needed to pump out water from the hole. High-tension cables strung on metal posts are being installed in Mackinac County along I-75 to save lives and reduce injuries. The cable guardrail system is engineered to stop out-of-control vehicles from crossing the highway median and crashing into oncoming traffic. The system already has saved lives in other areas of the state.

The St. Ignace portion of the $40 million state project will cost $2 million and includes the installation of 10 miles of the cable guardrail along a 23-mile strip of highway between the US-2 interchange north to the Mackinac County line. Tree-filled areas and sections of the highway with metal guardrails already in place are not included in the project.

A cable guardrail system is being installed along part of I-75 in Mackinac County. The Michigan Department of Transportation project is designed to save lives by stopping out-of-control vehicles from crossing the median. Wednesday, October 28, vehicles travel past a newly completed portion of the guardrail near St. Ignace. Work began in June and is expected to be completed next year.

The local project is part of a three-year statewide Michigan Department of Transportation (MDOT) program and is designed to improve highway safety. The department estimates that more than 13 lives are expected to be saved in the state each year from the system and about 51 incapacitating injuries are estimated to be prevented annually, said Bob Felt, an MDOT safety outreach specialist from the Gaylord office.

The cable guardrail system installed along I-69 in Genesee County captured this semi-truck and prevented the rig from crossing into the oncoming traffic lane January 13, 2009. (Michigan Department of Transportation photograph) State and federal engineers analyzed 340 miles of potential high crash locations across the state, he said, and determined 280 miles of highway would receive the cable guardrail system, including the St. Ignace area.

When a vehicle enters the center strip between the northbound and southbound lanes of traffic, explained Mr. Felt, the cable guardrail stops the vehicle from traveling into the opposing traffic lane. The metal poles that hold the cable are designed to "break away" or come out of the ground, although the cable remains taut, stopping the vehicle and absorbing its force, he said.

The cable, said Mr. Felt, does not bounce vehicles back into traffic, rather it captures them.

"The cable is designed to absorb some of the impact and catch the vehicle, which reduces injuries and saves lives. There is some concern that the cable guardrail will act like a rubber band and shoot people back into traffic, and that is far from the truth."

In June along I-94, said Mr. Felt, the driver of a van carrying 10 people lost control of the vehicle and headed toward the median. The cable guardrail stopped the van from crossing the highway median and driving into opposing traffic. No one was killed in the accident, he said.

The cable guardrail is being installed about 12 feet from the edge of the road, rather than the middle of the median, said Mr. Felt. The location helps maintain the integrity of the system, keeping it above standing water that can pool in the downward sloped median, and is easier to maintain.

The cable guardrail is a low cost solution compared to installing concrete barriers or a steel guardrail, he said.

Tri-Valley Landscaping of Saginaw, a company that specializes in highway construction, won the state bid for the St. Ignace project. The work of about 15 men is inspected by Stacy Sutela of St. Ignace, a construction inspector with MDOT's Newberry Transportation Center.

Right now, said Mr. Sutela, weather will determine the amount of work that will be done yet this fall. The crew is divided into two groups, with one group focused on drilling holes and pouring foundations for the breakaway posts. The other crew is responsible for installing the posts and stringing the tension cables.

The project began by preparing the ground for the installation. The ground where the system is placed was flattened and leveled for consistency. The holes for the foundations are drill with an auger and concrete is poured into the holes. A sleeve is placed in the concrete, which will hold the posts that are set about four feet deep. The posts, about 10.5 feet apart, are complete with reflectors and can be dislodged from the foundation when struck by a vehicle. At each end of a guardrail section are posts that anchor the tension cable.

Work is progressing slower than expected, said Brian Donovan, construction foreman with Tri-Valley. Crews are hitting a lot of rock, slowing the drilling process, and fall rains have soaked the ground, requiring crews to pump out the water from post holes during drilling.

"I wish it had been a dryer fall," he said.

Michigan is not the first state to install the cable guardrail system, which already is in place in Missouri, Washington, and South Carolina.

"The success rate is phenomenal," said Mr. Felt of the system. "About 90% to 95% of the vehicles captured by the guardrail are kept from crashing into opposing traffic."