With the state's fiscal woes making many major freeway improvements unlikely, and with severe geographic restraints limiting options, Caltrans was looking for an inexpensive way to reduce congestion and accidents on the notorious interchange of the 5 and 110 freeways near Dodger Stadium.
The agency came up with fluorescent bluish-white lights and electronic warning signs.
Until recently, motorists crawling out of downtown Los Angeles on the 110 north queued up in the far left lane to transition to the 5 north. But beginning last week, cars have been able to use a second lane to get onto the 5 during the peak afternoon rush hour.
The new lane didn't involve any major construction. Rather, officials embedded bluish-white light beacons in the roadway and added new electronic signs that help guide motorists.
The signs direct motorists to the two far-left lanes of the 110 onto the 5. Normally, drivers use only one lane of the 110 to get to the two-lane connector to the 5, so this essentially doubles the capacity of the connector.
"It's almost like turning on the faucet when you need it and turning off the faucet when you don't," said Frank Quon, deputy district director for operations at the California Department of Transportation.
Transportation planners have high hopes for the so-called dynamic lane, which Caltrans officials said is the first in California.
If the project at that interchange works, planners hope to expand the idea to other jammed freeway interchanges at minimal cost. This project cost $3.2 million, far less than most freeway improvement projects.
Officials have had the lighted beacons in the roadway for several months. Now that the signs are up and the dynamic lane is functioning, it will take some time for motorists to get used to it.
Some drivers said in recent days that the system is confusing and some motorists don't appear to realize there are now two lanes merging into the 5 north.
Angela Nordhagen, an insurance policy officer who has been commuting from Tujunga to downtown L.A. for more than 15 years, said she's not sure what to make of the new lights and signs. Despite the new dynamic lane, some drivers last week were still swooping into the northbound 5 transition lanes at the last minute. Others, including her, were confused about whether they could use the second lane to merge.
"I don't know how defined the lights really are," Nordhagen said.
Caltrans says that California Highway Patrol officers will be watching the intersection to check on how drivers are adjusting.
"This is the forefront of technology in traffic management," said Hamid Bahadori, senior policy analyst for the Automobile Club of Southern California. "It's getting attention mostly because our system is pretty much at capacity all over the place, and any capacity enhancement is exponentially expensive."
Bahadori said the dynamic lane is an example of a larger national push toward "adaptive traffic-control systems" that are responsive to real-time data on freeways.
He said using this type of technology to reduce congestion is important because widening freeways is often prohibitively expensive and in some areas, as at the 110-5 interchange, there are severe geographical constraints.
The dynamic lane on the 110 is in operation only between 3 and 7 p.m. on weekdays, but Caltrans officials hope to soon be able to turn the lane on and off at other times when traffic and congestion dictate.
The 5-110 interchange is considered one of the most congested in the region.
In addition to lessened congestion, Caltrans hopes to see a reduction in accidents at the interchange. From January 2006 to December 2008 there were 73 accidents there, most of which were rear-enders and sideswipes. Caltrans considers that number high.
Some motorists say improving the merging of traffic onto the 5 north would make the interchange safer. Motorist Tony Perez, who is familiar with the interchange, said traffic merging onto the 5 can be barely moving while cars continuing on the 110 toward Pasadena "are doing 60."
Lyla Forlani, 35, who works for the L.A. Opera downtown, decided not to use the 110 to the 5 some time ago because of the traffic backups, taking surface streets instead.
But the Los Feliz resident is curious enough about the new system that she said she might try out the freeway again -- if the congestion eases.
Caltrans hopes to have numbers on traffic times in several months.