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The Pasadena Freeway (SR-110) was built in 1940, and originally carried 27,000 vehicles. Today, Average Annual Daily Traffic volume at the northbound SR-110 connector to I-5 is 127,000. No where to build? Sounds like a job for -- Technology.

A NEW PLAN FOR AN OLD FREEWAY
by  Judy Gish
Issue Date: 03/2009

"Dynamic" lane on northbound SR-110 will do double duty as both a through lane and a connector. How? Lights, cameras and lots of signs.

How do you solve a modern problem on a historic freeway tunnel where there is no room to expand? With modern technology, of course. District 7 is implementing a brand new solution never attempted anywhere else in the state, which is to create a “Dynamic” lane on the Arroyo Seco Parkway (SR-110) at the northbound Golden State Freeway (I-5) connector.

Clearly, current population and traffic growth was not envisioned in 1940, when SR-110 was built, or it never would have been designed with a one-lane connector through a tunnel to one of the State’s most vital transportation facilities. As it is, a significant traffic queue develops in the connector lane during peak hours. Many motorists (the naughty ones) remain in the Number 2 lane until just before the connector and cut over at the last minute, resulting in a significant number of rear-end and sideswipe accidents.

The solution: Turn the Number 2 lane into a connector lane during peak hours and allow it to function as a through-lane on SR-110 during general hours.

“The project proposes the development and deployment of an active lane management system based on real-time traffic demand,” said Senior Transportation Engineer Sheik Moinuddin of the Traffic Investigations Office. During the initial phase, expected to go into operation some time this month, the system will be activated on a fixed time basis between the hours of 3 p.m. and 7 p.m. on weekdays only. “Following the initial phase, the system will be activated based on real-time traffic demand,” he said.

Lane management will be accomplished using three Extinguishable Message Signs (EMS) in series. The first will be installed around the Hill Street on-ramp, before the first tunnel; subsequent EMS will be installed before the second and fourth tunnels. An electronic lane assignment sign at the gore point will also assist motorists in choosing the correct lane.

As part of this system, lighted pavement markers, or Smart-stud systems, will be used to guide and enforce the use of lane Number 2 as an optional lane. The Smart-studs will be placed between lane Number 1 and lane Number 2 as delineators. During peak hours, the lighted pavement markers will be turned off, thus allowing motorists to use lane Number 2 as an optional lane for northbound SR-110 mainline or to the northbound I-5 connector. During all other hours, lighted pavement markers will be turned on displaying a continuous light between lane Number 1 and lane Number 2. Near the connector, the lighted pavement markers are installed so closely that, when lighted, they will mimic a solid white line, prohibiting motorists from using lane Number 2 as an optional SR-110 lane.

Smart-stud is a road marker guidance system that is highly visible in any weather or roadway condition. Each Smart-stud is lit with ten or 20 high-intensity LED lights, visible from up to 500 meters away. “Smart-studs are inductively powered and therefore have no direct wire connections,” Moinuddin said. “They are cost effective to install and run, as well as highly durable even in the heaviest traffic conditions.”

Lighted pavement markers and the EMS will work in conjunction so that when pavement markers are turned off, the EMS will be turned on to allow motorists to use lane Number 2 as an optional lane, and vice versa.

“We believe this is the best solution to congestion at the connector given the constraints of the geography,” Moinuddin said. “It’s a great example of technology helping us to drive smarter.”

Senior Transportation Engineer Sheik Moinuddin is working on the SR-110 Dynamic lane project. Motorists will be guided by lighted pavement markers, or Smart-stud systems, to use lane Number 2 as an optional lane.  This drawing illustrates what the new signage would look like.