High occupancy, low usage

As costs mount, zipper lanes face new questions about future role

By David Abel
Globe Staff / March 8, 2009
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Before dawn and dusk every weekday, the large, lumbering machines crawl along the Southeast Expressway, gobbling 750-pound concrete barriers at one end and spitting them out in seamless rows at the other.

The heavy lifting required to open and close the so-called zipper lanes on the 6 miles of Interstate 93 south of Boston has become increasingly expensive as the Pac-Man-like trucks get older and a dwindling number of vehicles use the high-occupancy lanes.

On an average day in January, fewer than 7,000 vehicles - cars with two or more occupants, motorcycles, and emergency vehicles - used the zipper lanes, a 20 percent drop from the average peak use three years ago.

The 14-year-old barrier transport vehicles are well beyond their intended lifespan and will have to be replaced in the next few years at a cost of more than $1 million apiece. As lawmakers debate how to pay for the deteriorating transportation system, the high replacement cost raises questions about whether the state should continue an operation that already costs taxpayers $1.25 million a year.

"Given the small amount of vehicles using the lanes, common sense says it may not be worth it to continue," said Art Kinsman, a spokesman for AAA Southern New England. "With tax revenues what they are today, the state should reevaluate whether it would be better to use the money for something else."

While the state has no plans to close the zipper lanes, which run from the Braintree split to Dorchester, others are calling on officials to open the lanes to solo drivers as a means of raising revenue, as have seven other states.

Last week, the Massachusetts Taxpayers Foundation encouraged state officials to join a federal program to convert the high-occupancy vehicle, or HOV, lanes on I-93 into high-occupancy toll, or HOT, lanes. The idea would be to allow single-occupancy vehicles to pay a toll to use the zipper lanes. Carpoolers would still drive for free, but solo drivers would pay to use the lanes with transponders.

"If we just made up for the drop in users of the HOV lane, it would begin to pay for itself," said Andy Bagley, a spokesman for the Massachusetts Taxpayers Foundation.

"Rather than get rid of the HOV lanes, this would make them more useful," he said. "No one would have to pay a toll who didn't want to, and it would reduce congestion on the rest of the highway."

Transportation officials say they have no plans to introduce a tolling system for solo drivers. To do so, they said, would require changes in the state's environmental regulations and a plan to offset any increased pollution.

They attribute much of the decline in the last three years to the slowing economy and fewer people driving to Boston for work, even though the overall number of vehicles using the Southeast Expressway increased during the same period. On average last year, 185,200 vehicles a day used the highway, up nearly 4 percent from 2006.

Luisa Paiewonsky, commissioner of the Massachusetts Highway Department, argued that the zipper lanes are worth their cost and that opening them to solo drivers would hinder their environmental benefits and reduce the incentive of a speedy commute for carpoolers. She estimated that traffic in the zipper lanes would slow if they attracted 10,000 vehicles a day.

"We don't want to risk undermining the purpose of the HOV lanes," Paiewonsky said. "We should have enough vehicles to make sure the public investment is being used, while also making sure there's an incentive to use the lanes and reward those who use them."

But federal transportation officials said that opening HOV lanes in other states has helped to promote carpooling and reduce congestion.

"The conversion of HOV lanes to HOT lanes has shown it improves traffic flow," said Nancy Singer, a spokeswoman for the Federal Highway Administration, which has provided financial assistance and administrative approval for states from Florida to Washington to make the change. "And with less congestion, the air quality is certainly better."

In Denver, which made the conversion in 2006, the number of vehicles using the HOT lanes has increased to an average of 12,000 a day, 20 percent more than when they were HOV lanes. Colorado has also recouped the costs of the program, taking in more than $3 million a year in tolls and fines, nearly $1 million more than the system costs.

Like other states with HOT lanes, Colorado controls the traffic using variable pricing, charging as little as 50 cents to use the lanes in off-peak hours and as much as $3.50 in rush-hour periods. The lanes are monitored by police, and carpoolers and solo drivers enter from different points, at highway speeds.

"The lanes have been very successful," said Mindy Crane, a spokeswoman for the Colorado Department of Transportation. "We no longer underutilize the lanes, and it has helped with the overall flow of traffic."

Frequent commuters to Boston such as state Senator Mark C. Montigny, a New Bedford Democrat who serves on the Legislature's Joint Transportation Committee, said the state should consider the conversion.

"Absolutely, I think this should be on the table," said Montigny. "There shouldn't be an incentive for people to commute alone, but if this would help reduce congestion, we should explore it."

Stephen Silveira, former chairman of the state's Transportation Finance Commission, estimated that if 3,000 solo drivers paid $1 each way to drive in the zipper lane, the state would earn $1.5 million, more than covering its costs. "I think it would be worth $1 for a lot of people to get home 20 minutes faster," he said.

For now, the state avoids the expense of replacing the massive yellow trucks, which rearrange the zipper lane's 10,000 Jersey barriers twice a day, by relying on the tender care of Rob Bodoin and his fellow mechanics.

The machines were supposed to last no longer than a decade, but Bodoin, who drives and repairs them, has kept them moving at their average 5.2 miles per hour every weekday. He compares his job to running a NASCAR pit crew.

"It's all about maintenance, but we have to do the maintenance very quickly," he said. "We can't be late to open the lanes."

On a recent morning closing the southbound zipper lane, Bodoin stopped the truck and got out to remove a piece of metal on the road. Other obstacles he has come across include lawn furniture, mattresses, cellphones, clothing, and a variety of animal carcasses.

"We're careful," he said. "We don't want to destroy the machines."

David Abel can be reached at

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