Even a gray morning will put a highway in a wall. It is the pitfall of motorists on the Highway 99 in California when the heavy Tule fog goes down the Central Valley and they can hardly see through a few car lengths. During the collision on the earlimart road, drivers were faced with zero visibility and a chain reaction that was spread over the lanes and left the road block of considerable length with the drivers unable to move forward as the crews searched through the messy trails of wreckage.
The fog pileups are attractive due to their size, yet their mechanics are obstinately the same: speed encounters surprise, and surprise does not allow a hold-up. According to Caltrans, almost three out of four motor vehicle crashes caused by fog are linked to excessive speeding of drivers. Practically “too fast” may be that which is comfortable at an empty morning and is unsafe when the view is reduced to hundreds of feet. The issue is worsened due to the fact that every hard brake in the rear of the “sudden stop” forms another point of impact, and every new point of impact forms a hindrance on the cars that continue to enter the fog. When big rigs are on the table the stakes lengthen in a short period of time: increasing mass, increasing stopping distance, and possible to obtain smaller vehicles that would be crushed and would result in slower and more dangerous rescues.
Local geography can be used to understand the reason such an emergency continues to recur. The tule fog occurs when wet ground gives out moisture, which fills the cold still air; the bowl-shaped terrain of the San Joaquin Valley can retain that air there. The persistence was bluntly explained by meteorologist Emily Wilson: “The persistence simply continues through the afternoon due to the meteorological physics.” “And it is even a hard task to make predictions, at least a seasoned meteorologist,” I added. This uncertainty is important to commuters and freight traffic since what was an acceptable route at the beginning of the day can suddenly become hazardous, particularly in rural areas where the sun and adjacent urban heat fail to clear the fog as fast.
The information that officials focused on following the Earlimart pileup was not much, but it can prove to be very decisive: headlights. The county officials cautioned motorists against thinking they are safe because they have automatic headlight systems that will save them during foggy days. When it is thick fog, keep off and DO NOT trust to automatic headlights, they said. Due to the absence of darkness, Headlights and tail lights are not on, and your car is almost invisible. Remember to turn on your Headlights manually, that way other people can see you. The reason is that it is visibility in both ways: it is half the battle to be able to see ahead, and a car without tail lights is practically an undetected object in a traffic jam that has already had its share of trouble in determining distance.
The thing is that history is what makes Highway 99 feel so unforgivingly unique. The Fresno Bee archives report of recurring fog disasters up and down the road, such as 86 vehicles crashing in 2007, and several multi-dozen car crashes during the 1990s. All those accidents, spanning decades and counties, speak of how intolerant fogs of everyday routine have grown to be the tight following distance, changing lanes to “get moving”, and high beams that fling light right back into the eyes of the driver.
Caltrans instructions on dense fog are straightforward, yet they are made to apply in the event of a failure of instinct, namely, to slow, maintain a greater distance between vehicles, and to drive at low beams instead of high ones. During the winter fogs in the Central Valley, the underlying decisions are less prudent than they are on the roads when the view can intrinsically disappear without warning, making physics a negotiable subject.
