A red SMART car was pulled over by El Cerrito police at about 7:30 a.m. on westbound I-80 on-ramp from Potrero Avenue, Richmond police spokesman Lt. Felix Tan said.
Police say the suspect, who works at a local auto-repair shop borrowed the car and the customer who owns it had no idea the crime occurred.
RELATED: 3-year-old child hurt in hit-and-run crash in Richmond
The hit-and-run was reported at about 11:30 a.m. Wednesday in the 2700 block of Macdonald Avenue, Tan said.
Officers learned that the 3-year-old boy was with his mother as he was about to get into their car parked along the curb, but escaped his mother's grasp and darted into the street where the car struck him, according to Tan.
The driver of the red Smart car, which has a black top and was believed to have damage to its front end, fled in the vehicle.
The boy was described as being critically injured Wednesday and Tan said this morning that his condition is now "critical but stable."
Anyone with information about the incident is asked to call police at (510) 233-1214.
ABC7News' Eric Thomas contributed to this report.