A decision to "go for it" and overtake a campervan as well as a station wagon cost a mother her life.

Lisa Lyon died in a head-on collision at Four Mile Bridge on State Highway 6 near Charleston on May 7, 2009.

A report by Coroner Richard McElrea includes evidence from her husband Derek Lyon who was sitting in the passenger's seat. The couple's sons, aged four and six years, were in the back seats and all family members were wearing seatbelts.

Mr Lyon said his wife pulled out to overtake a grey station wagon on a straight road before the bridge.

"Lisa then decided to overtake the campervan and I told her to pull in behind it. Lisa decided to go for it and continued on with the overtaking," he said.

She was travelling at 120km/h when he saw the oncoming vehicle.

Another coroner's report released on Monday says that Melissa Mahia, who was 12 weeks pregnant, was travelling in a Lexus at between 128km/h and 147km/h when she lost control and hit a power pole on Ruahapia Road near Hastings on November, 10, 2011.

She may have been eating a pie before the accident.

Coroner Tim Scott recommended that trees be removed near a railway crossing near the intersection of Jacksons Road and Koputaroa Road south of Levin where Rosalyn Sylvia Yong died on December 11, 2011 after a collision with a locomotive.

Sun strike, or the distraction of a dog in the car, may have been a cause in that accident.

"There may have been any one of a number of reasons why Sylvia did not see the approaching locomotive and/or there may have been a combination of these reasons," the coroner said.