Yet another motorist plunged into a Metairie canal over the weekend, this time doing so despite the presence of a guardrail.

Jefferson Parish has seen a half-dozen such accidents since April.

In the incident Sunday morning along Vintage Drive, the driver — a 23-year-old woman from Waveland, Mississippi, who said she fell asleep at the wheel before 8 a.m. — swam from her car unharmed.

Others have not been so fortunate. Three people have lost their lives in the recent spate of crashes, including a woman and her 6-year-old daughter.

The parish hired six engineering firms earlier this month to study stretches of canals in East and West Jefferson to figure out a feasible way to help prevent motorists from ending up in parish waterways.

Councilman Ben Zahn, who along with Councilwoman Cynthia Lee-Sheng pushed for the parish to conduct the studies, said he was at the scene at Vintage and Wilson drives as tow trucks pulled Ashley Lanning’s white Volkswagen Jetta out of the canal Sunday morning.

Although the Jefferson Parish Sheriff’s Office could not say how fast Lanning’s car was going at the time, Zahn said it appears that speed played more of a role in this accident than the others.

JPSO spokesman Col. John Fortunato said the car took out about 40 feet of guardrails and pilings, and Zahn said that suggests it was traveling quite fast.

Zahn said each accident has been different, and he still feels that guardrails are important.

He said Lanning, who declined medical help and left with only citations for disregarding a stop sign and careless operation of a vehicle, could have been more seriously hurt had the guardrails not been there.

“I think there’s still a need for guardrails,” Zahn said.

The accident “shows that putting guardrails up is not going to stop you from going into the canal if you’re speeding, but it could help save lives,” he said.

In early June, a man went into the canal along West Esplanade Avenue but managed to stop just short of going into the water.

In April, 6-year-old Karissa Wise and her mother, Elizabeth Braddock, died after their SUV crashed into a canal at Veterans Memorial Boulevard and Clearview Parkway.

Just a few days earlier, firefighter David Yeomans, 33, entered the canal on West Esplanade at some point on or shortly before the morning of April 9, when someone spotted his half-submerged truck and called first responders. His body was found inside the vehicle.

Also this spring, a mother and child were rescued from an SUV that barreled into the West Esplanade canal near Toby Lane, also in Metairie.

The firms studying the East Bank roadways are Pivotal Engineering, Digital Engineering and ECM Consultants. Rahman & Associates, URS and Professional Engineering Consultants will study the West Bank.

The parish should get reports from the engineering firms in four to six months.

There are a number of factors to consider in deciding whether and where to install more guardrails. The parish has 340 miles of unprotected canals, and areas that get guardrails would need pilings deep enough to withstand crashes without weakening the canal banks, parish officials have said.

Follow Chad Calder on Twitter, @Chad_Calder.