Two men died in two separate crashes on the Big Island over the weekend.

Shortly before 7:50 p.m. in Kealakekua Friday, police said a 1992 Mazda two-door convertible sedan operated by Robert Weeks, 48, of Hilo was traveling north on Highway 11 when he failed to negotiate a right curve near the 99-mile marker.

The vehicle ran off the roadway and overturned into an embankment. Paramedics transported Weeks to Hilo Community Hospital where he was pronounced dead at 1:54 a.m. Saturday.

Police said speed and inattention were involved.

The second fatal crash involved a motorcycle and a sedan in Kailua-Kona.

Police said Elvis Sheppard, 43, of Kailua-Kona was killed in the broadside collision.

At about 7:30 p.m., a 2016 Honda motorcycle operated by Sheppard was traveling east on Hinalani Street when a 2006 Kia four-door sedan operated by a 61-year-old man also of Kailua-Kona, failed to yield the right of way to the motorcycle.

Police said the sedan driver broadsided Sheppard who was making a left turn onto Hinalani Street from Kamanu Street.

Paramedics transported Sheppard to Kona Community Hospital in critical condition. He succumbed to his injuries and died at 10:24 a.m. Saturday.

Police said the 61-year-old driver was uninjured.

Speed and inattention were factors in the crash.

Weeks and Sheppard’s deaths were the eighth and ninth traffic-related fatalities, respectively compared to 10 at the same time last year. Autopsies are expected to be conducted to determine the exact cause of deaths.

The Hawaii Police Department’s Traffic Enforcement Unit has initiated a negligent homicide investigation into the Kailua-Kona crash. Anyone who witnessed the collision is asked to call Officer Justin Hooser at 326-4646.

Police are also asking for individuals who witnessed the Kealakekua crash to call Officer Christopher Kapua-Allison at 326-4646.

Tipsters who have information on either case also may call CrimeStoppers at 961-8300.