Mark Pendleton, 49, was riding south on McEwan Road near state Highway 4 between 5:45 p.m. and 6 p.m. when he was hit, California Highway Patrol Officer Scott Yox said.
According to Ross, the ride was one of Pendleton's favorites.
Investigators believe the vehicle, possibly a Chevrolet Silverado or similar model pickup truck or sport utility vehicle, crossed over into the southbound lane and hit Pendleton, who was riding close to the west shoulder, the CHP said.
An off-duty fire captain from Crockett spotted Pendleton just after 6 p.m. and called for medical assistance, but Pendleton died at the scene.
CHP officers handed out flyers Tuesday evening near where the collision occurred, hoping motorists might remember seeing something that could point the CHP in the right direction, Yox said.
According to Yox, investigators have been able to start to piece together some information based on chatting with motorists and on phone calls that came in from people who heard about the crash.
Investigators were also able to narrow the time frame of the crash to about a 15-minute period after a motorist driving in the area around 5:20 p.m. the day of the hit-and-run reported a bicyclist that may have been Pendleton. The motorist reported being startled by the rider because he appeared to be riding without lights or reflectors.
Another motorist was driving northbound on McEwan Road around 5:45 p.m. when she noticed a vehicle behind her that, based on the position of the lights, may have been a pickup truck or sport utility vehicle.
Yox said the woman said she rounded a corner and was also startled by a bicyclist riding on the shoulder with no lights on his bike. A short time later, the motorist noticed that the truck or SUV was no longer driving behind her, Yox said.
A third motorist said a truck was spotted pulled over on the side of the road around the time when the collision may have occurred, Yox said. Debris left at the scene appears to match a Chevy Silverado or similar model, Yox said.
Investigators were working today to determine what color the vehicle might have been.
Investigators are also tracking down people who attended a party hosted by a Pleasant Hill man who is dating a Port Costa resident, Yox said.
"Obviously it would look better if the person turned themselves in," Yox said.
If found the driver could face felony hit-and-run and vehicular manslaughter charges. If there is any evidence that the person was drunk at the time of the crash, the charges could be raised to gross vehicular manslaughter, which carries a stiffer sentence.
Anyone with information about the incident or who has seen a vehicle with recent front-end damage is asked to call (925) 646-4980 or (800) TELL-CHP.