At Klein's truck stop many drivers chose to delay the start of their morning rather than deal with driving in its pea soup.
This is the first fog season for 12-million dollars worth of fog sensors and cameras along the 13 mile stretch of highway 99 between Tulare and Fresno counties.
When activated by fog, electronic messages are automatically sent to signs alerting drivers of the thick fog.
The CHP says despite the new technology drivers still have to do their job.
"When they see that wall of fog coming at them, if they can't see past that, they need to slow-down, they need to really watch where they're going," said CHP Axel Reyes.
Bus drivers say they need at least 400 feet visibility to drive children to school.
By 10 a-m yesterday... Visibility was only 200 feet in some parts of Tulare county.
Oak Valley Elementary school canceled classes altogether.
"We finally saw that it wasn't gonna clear and it was too dangerous for the buses so we had to cancel altogether," said Oak Valley Superintendent Kerry Beauchaine.
By 4:35 Thursday morning, schools --in Madera Unified were already announcing delays.
The CHP paces when visibility gets below 500 feet... when you come upon a pace car... Don't try to pass them.
