Office of Operations
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21st Century Operations Using 21st Century Technologies

Traffic Bottlenecks

Combating Bottlenecks

Los Angeles

A new high-tech system from New Zealand will be installed on L.A.'s 110 freeway, which will feature sensors that will know when traffic slows and open an alternate lane automatically.

Bottleneck Project: In November 2009, Caltrans expects to inaugurate a "dynamic lane" from the 110 freeway to the NB 5 freeway. When traffic slows and backs up in a tunnel at this connector the pavement-imbedded "smart" lights will engage to open up a second lane. Although the product (similar to a lane reflector) has been used elsewhere in the U.S. for typical lane accentuation, the $3.2M project is the first to employ dynamic lane use. A New Zealand company produces the "SmartStuds" lights, which are independent units that convert magnetic energy to electrical energy (known as inductive power transfer), which allows them to function independently from a fixed-cable system. Energy is delivered by a central cable that emits the magnetic field, but the studs do not have to be fixed by electric wires. The SmartStuds will transmit data that will help induce the switch from one lane to two, including sending messages to electronic roadway signs to alert motorists of the lane operation. The 110 / 5 junction is a persistent bottleneck, but is constrained by a reservoir on one side and a cliff on the other, so the agency can't make traditional widening changes. Initially the system will operate between 3 and 7 p.m. but eventually may operate dynamically during any perceived peak condition. Why not just operate two lanes full time? "Because cars (at speed) need to slow down before driving on the curved connector," said Sheik Moinuddin, a senior traffic engineer with Caltrans. During choked conditions, when speeds are low, two narrow lanes can help to mitigate the congestion. "With a dynamic system, we can balance the flow (to the demand)" says Moinuddin.