RAIN ACCIDENTS HAPPEN EVEN WHEN YOU ARE CAREFUL

Although Southern California is known for its relatively dry climate, rainfall can substantially increase the risk of automobile accidents throughout the San Fernando Valley. Communities including Sherman Oaks, Encino, Tarzana, Woodland Hills, Reseda, Northridge, Van Nuys, North Hollywood, Studio City, Chatsworth, and Granada Hills experience driving hazards when rain reduces visibility, decreases tire traction, and makes road surfaces slippery.

Unlike regions where motorists routinely drive in wet weather, Southern California experiences extended dry periods followed by occasional significant rainstorms. These conditions create particular challenges.

During dry periods, motor oil, grease, tire residue, and other contaminants accumulate on road surfaces. When rainfall begins, water can mix with these substances and reduce traction, particularly before sufficient rainfall washes away the accumulated material.

The danger is compounded by congested freeways, high-speed traffic, and drivers who fail to adjust their speed or following distance.

Research demonstrates that rainfall is associated with a substantial increase in automobile collision risk.

A University of Southern California report discussing research into Los Angeles traffic accidents found that drivers were approximately 80% more likely to experience an accident during rainfall than under normal, clear conditions. The report also described an average 140% increase in accident counts during wet weather, depending on the comparison used.

These findings are particularly relevant to the San Fernando Valley, where major freeways and heavily traveled surface streets carry substantial daily traffic.

 

The Five Principal Causes of Rain-Related Accidents

1. Reduced Tire Traction

Rainwater can reduce the friction between automobile tires and the roadway.

This makes braking, accelerating, and turning more difficult.

Drivers operating vehicles with worn tires face additional risks because insufficient tread depth can impair the tire's ability to disperse water.

2. Excessive Speed

A speed that is reasonable under dry conditions may become unsafe during rainfall.

California Vehicle Code §22350 requires motorists to operate at a speed that is reasonable and prudent considering weather, visibility, traffic, and roadway conditions.

Consequently, driving at the posted speed limit does not automatically establish that a motorist was traveling at a safe speed.

A driver traveling 45 mph in a posted 45-mph zone may nevertheless be traveling too fast when heavy rain substantially reduces visibility and traction.

3. Following Too Closely

Rear-end collisions are a significant concern during rainy conditions.

California Vehicle Code §21703 prohibits following another vehicle more closely than is reasonable and prudent.

Wet pavement can increase stopping distances.

A driver who maintains the same following distance used during dry weather may be unable to avoid striking a vehicle that suddenly slows.

4. Hydroplaning

Hydroplaning occurs when water separates a tire from effective contact with the roadway.

When this happens, the driver may lose steering and braking control.

The risk depends on several factors, including water depth, vehicle speed, tire condition, and pavement characteristics.

Hydroplaning can result in lane-departure accidents, collisions with guardrails, and multi-vehicle crashes.

5. Reduced Visibility

Heavy rainfall can interfere with a driver's ability to recognize vehicles, pedestrians, traffic signals, and roadway hazards.

Water spray from trucks and other vehicles can further reduce visibility.

California Vehicle Code §24400 requires headlights under specified conditions, including when windshield wipers must be used continuously because of rain, mist, snow, fog, or other atmospheric conditions.

Proper lighting helps motorists see and makes their vehicles more visible to others.