The Victorian Government has spent $1 million to stop the next “dickhead” from running into a notoriously low bridge.

Trucks and buses have struck the Napier Street bridge in Footscray more than 70 times in the past 12 years.

Every time it happens, trains on the Werribee line (which runs over the top of the bridge) are stopped, and experts are called in to check the structural integrity of the bridge.

The bridge now features a new $1.2 million detection system that uses laser beams to trigger flashing warnings and turn stop lights red to prevent tall vehicles from proceeding.

The new upgrade is in addition to the 28 height warning signs on the approach to the bridge.

“You've really got to be a dickhead in ignoring every sign to hit a bridge,” Roads Minister Luke Donnellan said.

“This is a more activist intervention to literally say; ‘Well if you are going to hit the bridge you will have had to ignore traffic signals’.

“You would have had to have gone through red lights and you would have to deliberately defy everything along the way to actually hit the bridge.”

A bridge on Montague St in South Melbourne has the same problem, and has seen

gantries with hanging flaps installed in recent years that are at the same height as the bridge, and designed to warn drivers when their vehicles are too tall.

“Even the Montague St bridge, [where] we've got creepy crawly spiders coming all over the truck before they hit the bridge and people still ignore that,” Mr Donnellan said.

“I mean I don't know what you do sometimes. It's just plain defiance.

“You've really got to be a driver who's just not paying attention and obviously has no interest in safety.

“It's not good enough that people continue driving trucks and ignore the messaging.”