AUGUSTA — Over the past 10 years, the number of crashes on Maine’s roads and highways has decreased, as has the number of accidents that resulted in injuries or death.

Still, troublesome intersections persist throughout the state. The Bangor Daily News has compiled information from the Maine Department of Transportation to identify where those intersections are and to ask why accidents persist in those locations and what the state is doing to improve motorists’ safety.

First, some numbers: Automobile crashes are down statewide since 2003, from around 35,000 per year to just more than 28,000 in 2012, according to the Maine Department of Transportation. Fatal accidents also are down, though the trend line has been up and down over the decade, from 202 deaths in 2003 to 163 in 2012.

Steve Landry, MDOT traffic engineer, said the reduction in crash numbers and fatalities is a result of the department prioritizing the most dangerous roads, highways and intersections. But he cautions against assuming areas with the most crashes are necessarily the most dangerous.

The department prioritizes safety projects in areas that have the most dangerous accidents, not the ones with the most incidents, he said.

“I could have an intersection that has only three crashes [over a three-year period], but if two of them are fatal, that’d be an area we really want to look at,” he said in a recent interview.

The department ranks intersections with a calculation called the “critical rate factor,” or CRF, an equation that factors in the number of accidents and average traffic, but not the severity of crashes. The idea is that an intersection with fewer crashes can be more problematic than one with more, if the lower-crash location also has a lighter traffic load.

The CRF does not allow for side-by-side comparisons of any two intersections, Landry said, but shows how dangerous a particular intersection is compared with similar ones. A score of 1 is considered “average,” with higher numbers corresponding with more troublesome areas.

So where are you most likely to get into an accident? Of those five most accident-prone intersections from 2010 through 2012, four are in the Augusta area. The most accident-prone is the four-way intersection of the Interstate 95 Exit 102 ramp, Gardiner Service Plaza entrance and Lewiston Road in West Gardiner, with a CRF of 21.68 and 27 accidents over the three-year period.

The second, third and fourth most accident-prone locations are all in Augusta: They are, in order, the intersection of I-95 South and Western Avenue at Exit 109B, with a CRF of 20.76 and 97 accidents; Cony Circle, the rotary on the eastern side of the Kennebec River, with a CRF of 10.7 and 126 accidents; and Memorial Circle, the rotary on the river’s western side, with a CRF of 10.41 and 107 accidents.

The fifth most accident-prone intersection is where Cumberland Street meets Warren Avenue in Westbrook, with a CRF of 9.75 and 66 accidents in the three-year period.

Over the next three years, MDOT’s work plan includes about $4.1 million in projects to improve those five intersections or the roads leading to them. If voters in November approve the $100 million transportation bond backed by lawmakers in the recent special session, those and every other project in the work plan will be fully funded, said Transportation Commissioner David Bernhardt.

Roundabouts and rotaries

The most extensive intersection project is the construction of a roundabout at the most accident-prone location on the list, where I-95 meets Lewiston Road and the Gardiner Service Plaza. Construction costs are expected to total $1,395,000.

Roundabouts and rotaries often are touted by traffic engineers as ways to improve intersections, and that’s the idea behind the plan in West Gardiner. So why are two of the top five most dangerous intersections at rotaries?

Landry, the state traffic engineer, said it’s because “taking away one set of problems often creates others.”

Traffic circles slow down vehicles and direct all traffic in one direction. That creates fewer potential “conflict areas,” at the intersection, he said. Because the cars are moving more slowly and all moving in the same direction, the likelihood of an accident causing injury or death is significantly lower, he said.

Put another way: “Three or four deaths in a three-year period, that’s a lot different than just breaking some glass,” Bernhardt said.

The two traffic circles on the list are also in the state’s capital. That means people from all over the state, many of whom have never navigated a rotary, travel through the area. Confusion or distraction could be why there are still so many fender-benders at Cony and Memorial circles.

It could also be sheer numbers, Landry said. The nature of Augusta’s traffic map means a whole lot of drivers are directed to the two traffic circles every day. More traffic always will mean more accidents, he said.

“There’s so much traffic going through there, there’s unfamiliar drivers coming through, and you’ve got people unfamiliar with the area,” Landry said. “People are going to and from the hospital, and if you’ve got a dying family member, you may not be in the right frame of mind. But I think it’s mostly volume. There are five major legs coming into [Cony Circle.] Most high-volume intersections have only four. That makes a big difference.”

Landry also stressed that “most dangerous” or “most accident-prone” are relative superlatives. There are also factors that have nothing to do with traffic engineering — such as the rise of smartphones and the associated accidents from distracted driving — that contribute to accidents.

“No matter what we do to fix the roadways out there, we’re always going to have high-crash locations because it drops the standard we measure from down,” he said. “We’ve seen overall crashes reduce for a while now, and something that might not be considered a high-crash location 10 years ago might be considered one today, because there are less total.”