Following two similar incidents in the past five months, a Southern Maryland resident jumped to his death from a highway bridge last week, prompting some officials and advocates to raise questions about how to modify bridges to deter suicides.

The two spans in question are the Gov. Harry W. Nice Memorial Bridge, which crosses the Potomac River from southern Charles County to Virginia, and the Thomas Johnson Bridge, which connects Calvert and St. Mary's counties across the Patuxent River.

Neither bridge has tall barriers or fences to stop people from jumping, which is not unusual. Neither bridge has emergency "crisis" telephones. There are 20 phones along the Chesapeake Bay Bridge and six on the Francis Scott Key Bridge.

"I think we can take what they've done [with phones] and move it to other bridges," said Lisa Hurka Covington, a suicide-prevention activist in Maryland who is president of Suicide Prevention Education Awareness for Kids.

She lobbied to get phones stationed on the Chesapeake Bay and Francis Scott Key bridges. "It gives the jumper one last time to maybe think about it twice," she said.

In Calvert, Anthony J. O'Donnell, the Republican leader of the House of Delegates, said constituents asked him late last year what measures could be taken at the Thomas Johnson Bridge. "I'm trying to learn about the phenomenon and what can be done," he said, adding that he is studying phones and barriers.

In the most recent incident, rescue workers on Thursday found the body of a 42-year-old Mechanicsville man in the Potomac, 300 feet south of the Harry W. Nice Bridge, said Cpl. Jonathan Green, a spokesman for the Maryland Transportation Authority Police. The man apparently jumped from the bridge Tuesday. Authorities found a 2000 Chrysler Sebring on the bridge. A passenger in that car witnessed the incident, Green said.

The bridge crests 137 feet above the water, Green said. But the man might not have died from the impact. Green cited hypothermia and drowning as contributing factors to his death.

A little more than a week ago, a 40-year-old Prince Frederick man allegedly abducted his estranged girlfriend from St. Leonard, bound her and placed her inside a car, according to the Calvert County Sheriff's Office. He then traveled to the Thomas Johnson Bridge, got out of the car and jumped. The woman apparently could see what he did, said Sgt. Mike Moore, a Calvert sheriff's spokesman.

The search for the jumper continued Friday. In October, a 42-year-old St. Leonard woman jumped off the same bridge. At least six people reportedly called 911 after seeing her jump. Rescue workers found her body the next day.

"The more recent incident [on the Johnson bridge] is most unfortunate and highlights some of the questions I am asking," said O'Donnell, the state delegate.

How to make bridges more suicide-proof is a vexing question across the nation. In San Francisco, the Golden Gate Bridge Highway and Transportation District is in the midst of a $2 million engineering and environmental study on erecting barriers along the scenic span. Engineers are conducting wind model tests to see what kind of barriers would be possible, a spokeswoman for the Golden Gate Bridge district said.

In the past, barrier proposals were dismissed in part because they would diminish the bridge's aesthetics. Since the bridge opened in 1937, more than 1,200 people have died after jumping off it, according to articles published by the San Francisco Chronicle in 2005.

In New York, the state's Bridge Authority this month approved the purchase of telephones at four Hudson River bridges. The phones will link to a national suicide prevention line. In December, two people died by jumping off the Hudson Valley's Kingston-Rhinecliff Bridge. In January, a distraught man climbed to the top of the Newburgh-Beacon Bridge but was talked down by police officers, according to the Associated Press.

Research suggests crisis phones and barriers can be effective, or at least should be considered. Other possible solutions include surveillance cameras and safety nets. David Gunnell, a British researcher, said barriers can slow down the attempt, which allows reconsideration or intervention. He listed the arguments against such measures, including cost and possible structural safety issues.

Telephones might not be a panacea. And with more and more people carrying cellphones, potential jumpers may already have a phone. In that case, suggested Hurka Covington, the Maryland suicide prevention expert, authorities might want to at least post strategic signs that list toll-free crisis numbers. She said permanent phones are important, because not everyone carries a cellphone. Even when such callers use a cellphone, she said, if volunteers could direct them to a permanent phone, police would be able to identify where they are.

Hurka Covington said her sister, Laura, fatally shot herself in 1991, and that has motivated her work. With barriers or phones or signs on bridges, she said, "If we can save one person, or save one family from what we've experienced, it's worth it."