The southbound lanes of the Coronado Bridge and Interstate 5 were shut down Monday morning after CHP found a suspected pipe bomb just north of the on-ramp to the bridge.
The one-foot pipe was found on the southbound shoulder of I-5 just after 8:30 a.m., said San Diego Police Department Lt. Hassen.
Officers said the tube had caps on both ends.
"We called for the San Diego Police bomb squad to come out and evaluate the device," said CHP Officer Art Athans.
CHP officers have been told to be on alert after the death of Osama Bin Laden.
"Because of the recent events of last night our officers have been briefed to be extra vigilant -- to be more aware of their surroundings," Athans said.
After a closer look, investigators said the pipe was some sort of inert military ordnance.
"There is no explosive device in it, a training device or something along that line," Athans said. "What exactly it is used for I do not know."
Investigators said the device was not hazardous and may have fallen off a passing vehicle.
CHP re-opened southbound lanes of traffic just before 10 a.m.