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Blog category: Driving

Why Does Traffic Happen in California?

5 min read

Traffic. It’s a well-known annoyance for California drivers. Even drivers who live outside of major metropolitan areas have likely experienced heavy traffic congestion from road construction or accidents. Many face traffic jams each day on their commute to and from their jobs. In a study by INRIX, three major California cities ranked in the top fifteen of U.S. cities for most traffic congestion. Traffic in Los Angeles was found to amount to over 100 hours a year.

We’ve all experienced — and hated — traffic congestion. But why does traffic happen? Traffic happens at the most basic level when a roadway has too many cars on it at once. Traffic is a complex system made worse by accidents, bad weather, and road construction. However, much of the day-to-day traffic jams on a commute are caused by drivers’ decisions.

This guide will help you understand how traffic starts and what leads to traffic jams.

Causes of California Traffic

The answer to “Why does traffic happen?” begins with too many cars. Many cars must slow down to make room for the new vehicles and to allow more cars to enter a busy roadway. The more cars on the road, the more vehicles must slow down to allow room for other vehicles. Since the state has more cars than any other, that’s where we begin to understand the traffic in California. Several other factors contribute to the Golden State’s traffic congestion.

Car Accidents

Auto collisions are a common cause of traffic congestion. Often, traffic must be narrowed to fewer lanes to allow emergency vehicles to maneuver. Even a large highway can have several lanes of traffic completely closed. Every vehicle must slow down to allow the lanes to merge, not to mention the inevitable rubbernecking by other drivers. The entire time a road is closed due to an accident, more cars enter the roadway, building upon the traffic congestion.

California is home to an estimated 1500 vehicle accidents every day.

Construction Zones

Construction zones are another common cause of traffic in California. Vehicles head toward the road construction at the normal speed limit, then slow to navigate around the construction. Even though drivers are usually aware of the construction, the sudden slowing of vehicles causes congestion. The section of road before the construction zone soon has more cars than it can handle at normal speeds.


Weather contributes to traffic in California in several ways. Rain and snow make the roads more treacherous, forcing traffic to slow. Fog and dust storms kicked up by high winds can reduce visibility, causing traffic to slow dramatically. Weather conditions like these also increase the rate of collisions, further increasing traffic congestion.

Traffic Caused by Drivers

In many ways, drivers' decisions best answer the question, “Why does traffic happen?”. From rush hour traffic or texting while driving to slowing to look at an accident and many other poor decisions, drivers’ choices increase traffic congestion.

Even the smallest adjustment by one driver can cause a traffic jam. Heavy traffic congestion not caused by an obvious factor such as an accident or construction, is sometimes known as a phantom traffic jam. In 2008, a Japanese study created a phantom traffic jam and studied the resulting “traffic wave.” Using a single closed track, the researchers instructed 22 drivers to maintain the same speed and distance between one another. After some time, drivers inadvertently began to speed up or slow down. These small adjustments created a ripple effect around the track. Each car slowed and sped, attempting to meet the speed of the car in front of it. The shifting speeds created a shockwave of braking and accelerating throughout the circle.

Many researchers believe that self-driving cars in sufficient numbers on the roadways will drastically reduce driver-caused traffic congestion.

Traffic in California

Why is there so much traffic in California? Whether you blame the number of cars on the roadways or the decisions of their drivers, the state has struggled with traffic congestion for decades. Traditionally, the state has added new highways and more lanes to the existing roadways, which you might assume would lessen the congestion. But it doesn’t seem to follow since the new and wider roadways attract more motorists, causing more traffic.

Traffic In Los Angeles

Traffic in the City of Angels has bedeviled city planners for over a century. The city’s explosive growth parallels private car ownership in the 1920s. Today, there are nearly twice as many registered vehicles in L.A. County as there are people. And, in a county covering 503 square miles, Los Angeles has about 650 miles of freeway.

The many high-rise buildings that pack more office workers into relatively small spaces intensify the rush hour traffic in Los Angeles. Additionally, the public transportation system is less robust than those in many other big cities in the US, So LA suffers from extreme traffic congestion from 7 am to 10 am and again between 4 pm and 7 pm.

Traffic in Sacramento

Traffic in Sacramento, California, ranks the 24th worst in the U.S. INRIX finds that Sacramento drivers lose 36 hours annually to traffic jams. Rush hour in the state’s capitol slows from 7 am to 9 am and 3:30 pm to 5 pm.

Traffic in San Francisco

The traffic in the City by the Bay has the dubious distinction of being the worst in California. INRIX ranks the city as having the 7th worst traffic congestion in America and the 15th worst worldwide! Drivers in San Francisco lose 97 hours annually to sitting in traffic. Rush hour extends from 7 am to 9 am and 4 pm to 6 pm.

Traffic in San Diego

San Diego’s weather, amenities, and thriving economy draw residents and tourists alike. Traffic congestion here is ranked the 5th worst in California and causes drivers to lose 54 hours annually. Rush hour is typically 7 am to 9 am and 4 pm to 6 pm.

Negative Effects of Traffic

In addition to being annoying or frustrating, traffic congestion can cause a ripple of negative effects. On top of delays and time wasted sitting in traffic, the following negative effects occur:

  • Heavier fuel consumption
  • Greater air pollution
  • More vehicle wear and tear
  • Road rage
  • Higher number of accidents
  • Slower emergency vehicle response
  • Increased stress

Traffic congestion’s negative effects increase drivers’ stress, which can cause reckless driving, accidents, and greater traffic jams. Using defensive driving techniques can help keep you safe in congested traffic.

Car Insurance with Wawanesa

Unfortunately, learning the answers to “Why does traffic happen?” doesn’t make it any easier to deal with. While Wawanesa can’t prevent traffic congestion, we can see that you’re protected on the road. Wawanesa provides competitive rates and award-winning customer service to ensure you have the information you need.

Call our friendly agents to help craft the ideal policy for your needs. Or get a free quote online today.

Drive safely!

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