An unidentified man driving a truck at about 3am alerted local police and a rescue team that he had found the wild bison lying in the middle of a road about four to five kilometres from the downtown district.
Officials found the heavily bleeding big gaur at the scene but it fled after people started gathering nearby.
An initial investigation found that it had been hit by a car, which apparently had been heavily damaged but was capable of driving. The animal was the hit again by a motorcycle, resulting in injuries to the rider, who was sent to hospital for treatment.
The rescue team continued efforts to locate the wild buffalo and a vet team from Khao Yai National Park was put on standby.
Officials and bystanders wondered how the gaur had found its way from Khao Yai National Park, which is about 40 kilometres away. Pak Chong market is within a few kilometres of the accident site.
The wild cow was red listed as a vulnerable species by the International Union for the Conservation of Nature in 1986.