Traffic Jam Causes: The Weird, Surprising and More Common

What causes a traffic jam? Sometimes the answer is obvious: construction, crashes or regular rush hour. Other times, it may appear to drivers that there’s no apparent reason for the traffic to be there. In order to get a better handle on how the flow of traffic works, let’s explore traffic jam causes, from the more common to the more rare.

What are the causes of traffic jams? We explain highway congestion.


The most common form of traffic occurs when there are more cars than the roadway can support. This form of congestion, also called saturation, is recurring, and makes up about half of all traffic that Americans experience on a daily basis, according to the Federal Highway Administration . Saturation often happens when a city’s population grows faster than its infrastructure. In places like Austin, for example, which is considered the fastest-growing city in the country, highway saturation is a critical issue that lawmakers have sought to address for years. Because sitting in highway traffic is seen as an unproductive and undesirable activity, recurring congestion can have adverse effects on both the economy and citizens’ well-being. In order to help solve the traffic congestion problem, you can get involved by learning about and voting on regulations that seek to improve traffic volume and poor infrastructure in your metropolitan area.


While it may seem frustrating to get stuck in a construction zone, interstate maintenance actually helps relieve traffic congestions in the long run. Types of construction that improve traffic flow might include adding more lanes to the highway, creating one-way streets and putting up traffic lights. If you’re sitting in traffic because of construction, you can be optimistic in knowing that these new developments will actually decrease your travel time in the near future.

Construction can cause traffic.

Car Crashes

Oftentimes, when drivers hit heavy traffic, they immediately wonder if there was a car accident. Car crashes disrupt traffic flow for several reasons. The wreck might be blocking the interstate so that no cars can get around it. Drivers might have to stop, slow down or move over so that emergency vehicles can make their way to the scene of the accident. Sometimes, even if a wreck has been cleared to the side of the road, drivers will “rubberneck,” meaning they will drive slower so that they can get a better look at the crash. Rubbernecking can create stop-and-go traffic even if cars involved in the accident have been cleared and emergency vehicles are present, so you should always resist the temptation to do so.


Bad weather interrupts the free flow of traffic because it makes drivers more cautious. While you might feel annoyed by drivers who are moving slower than usual due to rain, snow or ice, they are simply taking safety precautions. In fact, it’s advised to go slightly below the speed limit in adverse weather in order to decrease your risk for crashing. It’s better that you’re stuck in traffic gridlock for a bit than be the victim of a car crash.

Bad weather is a major factor in traffic density.

Distracted Driving

A newer form of traffic that is affecting cities more and more every day is actually the result of distracted driving. When drivers are distracted by their smartphones or other handheld devices, they might not drive at a constant speed, thus unintentionally increasing traffic density. Drivers might also get distracted at stoplights, which can affect traffic density once the light turns green. In fact, smartphone distraction at traffic lights can negatively impact regular traffic flow for an average of 27 seconds after you’ve stopped texting, according to the AAA Foundation . You should never text and drive, as it can not only increase traffic congestion, but also increase your risk for crashing.

Now that you know more about what causes traffic jams, are you more inclined to help prevent them? Take action by looking up traffic laws that your local and state governments want to pass, using carpools or public transportation to lessen the number of vehicles on the road, and pledging not to engage in distracted driving.

Krista Doyle
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