The "Fast & Furious" star died in November when the vehicle he was riding in smashed into a tree and street light and burst into flames in Santa Clarita, California.
His relatives are now considering the possibility the accident was caused by Botts' dots, which are raised, non-reflective plastic bumps that mark out the lanes on roads, reports tmz.com.
A coroner has concluded the deaths of Walker and his friend Roger Rodas, who was driving the Porsche car when it crashed, were an accident, but investigators are currently looking into the cause of the single car accident, with speed considered to be a factor.
"The family has been in touch with stunt experts, who have gone to the crash site and come back with what they believe is a solid theory. A speeding car that hits the plastic markers will hydroplane, causing the driver to lose control," said a source.
Meanwhile, Paul's loved ones are currently deciding how and when the actor will be laid to rest.