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Future Tech: ‘Smart’ road studs coming to L.A. freeways

July 23, 2009 | 10:27 pm


Imagine a future where you can charge your electric car by driving in a special freeway lane. Or where a driver can stick to the speed limit by following lights that pulse in sequence along the roadside. Or even one where traffic jams are a distant memory.

A little bit of the future is coming to L.A.'s freeways later this year in the form of "smart" road studs that gauge road conditions and traffic flow and open and close freeway lanes accordingly. Caltrans has contracted with a New Zealand company to pilot the "dynamic-lane" system on the northbound 110 Freeway where traffic backs up in a tunnel at the single-lane connector to the northbound 5 Freeway. At peak hours, the "smart studs" automatically will open a through lane on the 110 that will also serve as a connector, easing the long lines.

Pretty smart, huh? Caltrans thinks so. So do the tech guys at SmartStud, a unit of 3i Innovations, which is starting to gain serious traction in the U.S. after completing similar projects in tunnels across Europe, Australia and Canada. Despite a couple of delays -- the $3.2-million project had been set to roll out this month -- a Caltrans engineer says it's on target to launch in November and, if successful, could be installed at other L.A. County junctions.     

The road studs' smartness, according to Tim Crabtree of SmartStud, lies in their conversion of magnetic energy to electrical energy -- known as inductive power transfer -- which allows them to function independently from a fixed cable system. Energy is still delivered by a central cable that emits a magnetic field, but the studs do not need to be fixed by electrical wire to harness the electricity. A logical extension of the technology, Crabtree says, is a roadway-based system that can charge a vehicle's battery as it moves along, or a system of road lights that responds dynamically to a vehicle's speed.

Studs2 The studs used in the Caltrans project will have embedded sensors that can transmit information over the ACARS frequency widely used in aircraft monitoring systems. The data on traffic flow and road and weather conditions are sent to a control center, which relays the information to electronic roadway signs, alerting drivers to resulting lane changes. The Caltrans project requires about 650 of the LED lights mounted close together in twin lines.

Crabtree said a recent project in Germany's 5-mile Rennsteig tunnel required 20 miles of the lights in four lines. He said it's possible to install about two-thirds of a mile in one night shift. He said the studs, which are sunk at a minimum of four inches, are easier to install and replace than traditional light studs (as they are not connected to a central hub). Similar studs were installed in Santa Monica's McClure tunnel in 2003 to illuminate the freeway's center divider, but they aren’t used for dynamic lane changes.

Noting that the color of the studs will be white, as legally the LEDs have to match the color of the stripes they sit alongside, Crabtree added: "L.A.'s great, you can see the generations of installations of reflective markers. We recognize we need a product that's easy to replace; the problem is road dynamic. It's always moving, and hard-wiring does not last."

Sheik Moinuddin, a senior traffic engineer at Caltrans, told the Los Angeles Times that the dynamic-lane project is the first of its kind in L.A., and he's "optimistic" it will significantly reduce traffic jams and collisions. He said Caltrans was forced to innovate because the junction of the 110 and 5 freeways is at a historic, protected tunnel with a reservoir on one side and a cliff on the other, so the agency can’t make any major structural changes.

Studs3 He said that the system at first will operate between 3 and 7 p.m. but later, once drivers get used to it, will work automatically at peak-flow hours. "The embedded detectors on the roadway send feedback to a control center, which will operate automatically based on traffic demand to activate the second lane. But at the beginning we will have to let the motorists get used to this system."

So why not permanently open the second lane?

Because cars need to slow down before driving on the curved connector, Moinuddin said. A little bit of congestion, though annoying for drivers, can serve this purpose. 

"At this point, we can't have two lanes," he said. "Only at peak hours can we have enough volume to carry through the lanes. At peak hours the traffic moves slowly. In other hours it's low-volume, so speed will be the major concern.

"We aim to balance traffic volume between through-move and connector-move: If volume is low for the connector, then heavy for the through-move, it's a total imbalance. With a dynamic system we can balance the flow."

Although Caltrans says it has no plans to roll the system out further, Moinuddin says some potential for dynamic lanes exists at the 110 Freeway and 9th Street offramp, although some structural modification of the ramp would be necessary.

-- Craig Howie

Photos, from top: A long line at the connector lane to the northbound 5 Freeway from the northbound 110 Freeway; credit: Craig Howie. Smart studs in red and green; credit: SmartStud. Drivers sit for long periods in the single connector lane; credit: Craig Howie.