If entering a roundabout makes you fear you're about to crash, you're not paranoid.

Although the rotaries are built to ease congestion and lessen serious injuries, data obtained by the Times Union show the number of collisions increased after most of the roundabouts opened in the Capital Region.

Crashes increased at 15 of the 20 roundabouts built where a previous intersection existed, with fender benders even more likely to rise, sometimes dramatically, at two-lane rotaries. And while crashes were reduced at all the single-lane roundabouts built by the state, they rose at almost all those built by counties and towns.

Aggressive drivers are speeding through rotaries and failing to yield the right of way, said Mark Kennedy, director of traffic and safety for the state Department of Transportation in the Capital Region.

"We have found that single-lane roundabouts definitely reduce accidents," he said, referring to the state rotaries. "With multi-lane roundabouts, some are better, some are worse. There are two that are somewhat problematic."

In Malta, the roundabout at Route 9, Route 67 and Dunning Street went from an average of 7.8 crashes a year before the rotary to 45.7 a year afterward. In Bethlehem, the number of accidents at New Scotland Road and Route 140 jumped from an average of 9.6 a year to 38.3.

Two years ago, the state changed the signs and pavement markings at the Malta roundabout to help lessen the number of accidents.

"Those measures were not effective," Kennedy said.

Accidents in roundabouts tend to be less severe than at intersections with traffic lights. Rather than crash into each other head on or smack together in a T-bone crash, as drivers making lefts at conventional traffic lights often do, drivers in roundabouts tend to sideswipe and rear-end each other.

"The potential for high-speed, severe accidents is eliminated," Kennedy said.

At the Malta Diner, owner Steve Gouvis has a close-up view to the Capital Region's most treacherous roundabout. He said it has greatly lessened congestion but he is not surprised to hear crashes have risen.

"You hear a lot of honking during the course of the day," he said. "They control traffic effectively. You never have to wait more than five, six, seven seconds. They do work. I was a big skeptic."

But Gouvis said drivers appear not to always know who has the right of way.

"Most of them are minor accidents from people not accustomed to handling roundabouts," he said. "It's a hell of a lot safer than making left turns."

Brian Alymer and his daughter Maggie Alymer of Malta said they have adjusted to the rotary but see other drivers who are unfamiliar with it.

"I've watched the learning curve for local residents," Brian Alymer said as he sat eating lunch with his daughter at the Malta Diner. "What you see is a lot of people unfamiliar with roundabouts."

He said driving in them is simple: People just need to remember to yield to the person already in the roundabout.

Maggie Alymer recently moved to Malta from Illinois and said it took time for her to adjust to driving through the intersection.

"I don't have a problem with it. I did when I first got here," she said. "I will roll my window down and have to pay attention to what the cars are doing. You can't just roll into it."

Reed Hart of Hadley said roundabouts are good in theory but not in practice, given human nature.

"If people do what they are supposed to and cooperate, they work fine but people don't cooperate," he said while dining with his wife Pat at the Malta Diner. "There is no yielding."

His wife added that the intersection has too many blind spots.

At the Bethlehem roundabout, town resident Andrew Wickert said he became one of the accident statistics after the rotary opened. About a year ago, he rear-ended the car in front of him. Wickert had turned to look at traffic coming up alongside him and didn't realize the person in front of him had stopped.

"What I've learned is to stay in the far lane," Wickert said while standing in the parking lot of the nearby Price Chopper Plaza. "Even though I am a statistic, I am for it just because it keeps the traffic moving. Before, it was worse with the stoplights."

Another shopper, Elaine Verstandig, agreed. She said she was in an accident at the intersection before the rotary was built. On the day she spoke, Verstandig said, she had seen one person try to move into her lane in the roundabout and then stop in it. She watched a Volkswagen Jetta repeatedly circle the roundabout, its driver unsure how to get out to a main road.

"You have to know what you're doing," Verstandig said.

A lifelong resident of the town, she said, "the traffic is so much better."

This summer, both the Malta and Bethlehem roundabouts will get additional signs telling drivers to "Yield to All Lanes in the Circle." Markings that narrow as drivers approach the roundabouts will be added to the pavement to give drivers the impression their speed is increasing and they need to slow down.

In Bethlehem, the previous intersection was changed from one lane in each direction to two to reduce congestion. The result, however, has been that drivers enter the roundabout going too fast, Kennedy said.

Variable message boards warning drivers of their speed will be placed there this summer to get motorists to slow down, he said.

Not all the roundabouts in the Capital Region were built by the state. There are eight other roundabouts built by counties and towns.

All but one of the local roundabouts that are open are single-lane roundabouts, and all but one saw crashes rise. In many cases, the roundabouts are so new it is impossible to tell whether the rates will decline as drivers adjust to them.

The roundabout at Maxwell Road and Albany Shaker Road, built by Albany County, narrows from two lanes to one. It too has seen accidents rise slightly since it opened, according to Colonie town statistics.

In the first 10 months of operation, 20 crashes occurred at the roundabout, an average of two a month. In the prior three years, there were 48 or 1 1/3 a month. County officials say, however, that the change reduced the number of crashes along Albany Shaker Road between Wolf Road and Margaret Drive from an average of 14 a year to seven in the 10 months since it opened.

The accidents are not slowing down the construction of roundabouts in the Capital Region. There are two more, both with double lanes, under construction in Malta and another being built in East Greenbush.

"We've learned quite a lot about the design and operation of roundabouts" over the past five years, said James Boni, assistant to the state DOT's regional director. "If we were to design these problematic roundabouts today, we would have designed them quite a bit differently."

In reviewing crash data, DOT officials said they learned the accidents are not being caused by older people or those from outside the area.

"The accidents tend to be experienced drivers between 25 and 50 with a local zip code," Kennedy said. "It tells us that people familiar with the roundabouts and where they want to go, they are driving too fast. They are also choosing to be in the wrong lane."

To fully reduce crashes, drivers need to be more careful, said Carol Breen, a DOT spokeswoman.

"People do need to watch the pavement markings, watch the signs and be cognizant of their speed," she said. "People need to be very cognizant about yielding. If we can get at that driving behavior, we can bring these accidents down."

Reach O'Brien at 454-5092 or tobrien@timesunion.com.