A hacker in California is letting his disdain for President Donald Trump be known by way of a highway sign.

The electronic sign, placed to warn drivers about traffic delays, lit up with the words just before 11pm last night.

A passer-by snapped the image of the sign mocking President Donald Trump and shared it on Twitter.

The California Department of Transportation (Caltrans) said the Sacramento sign was placed there temporarily while a project to build a new bridge was underway.

But despite being locked with a password, hackers were able to bypass their security.

SEE PHOTO BELOW:

The brightly lit road sign was located in Sacramento, California