Community members said the streets are already dangerous, pointing to one fatal accident and a teenager left critically injured in the last year.
Police put out digital signs to encourage drivers to slow down since they legally cannot use radar because a traffic study expired in January.
Families expressed their frustration with speeders, yet CalTrans said it would like to increase the current 25 MPH speed limit.
"I would like to know what planet you are on to be raising the speed limit. It's the dumbest thing I've ever heard," said Thomas Slattery. His child was hit by a car.
CalTrans who is the governing authority over 3rd and 4th Streets, which is a state highway, insisted that a traffic study which it presented at Coronado City Council Tuesday night, showed that 85-percent of drivers go about 34 to 35 MPH on 3rd and 4th Street.
"Increasing the speed limit is not going to change the actual speed that the public is driving," said CalTrans District Division Chief, Marcelo Peinado.
Last month, a 70-year-old man was hit and killed crossing 4th Street, near A Street. The Slattery's 15-year-old son suffered a traumatic brain injury when he was hit by a car crossing 4th Street near B Street last year.
The Coronado mayor stood with the community.
"I can't count on CalTrans to help me," said Coronado Mayor Casey Tanaka.
Residents said no matter the speed limit, police need to enforce. The chief said 400 tickets were issued on 3rd and 4th Street last year.
"Pacing in that area is difficult, but it is something we can do in that area," said Chief Jon Froomin of the Coronado Police.
To help change driver behaviors, digital signs have been placed to encourage drivers to slow down.
Coronado families expressed their frustration with police and CalTrans.
CalTrans said they will work with the city on a plan, but the speed limit could increase as soon as a month. CalTrans also said it was considering putting up speed feedback signs to help slow down drivers.