Traffic patterns in a metropolitan region can be disrupted by what happens to just one vehicle. See this Washington, D.C. example involving a tanker truck:
A tanker truck overturned on the Inner Loop on the American Legion Bridge Thursday afternoon, closing the road and snarling traffic all over the D.C. area for hours.
Complicating the situation: That truck is loaded with 8,500 gallons of fuel, requiring a cleanup that will continue into the night. As of 8:45 p.m., about a quarter of the gasoline had been offloaded…
WTOP Traffic reporter Bob Marbourg stressed how tough it is to predict when lanes will reopen….
The accident occurred around 1:50 p.m., according to Corinne Geller of the Virginia State Police. Another vehicle struck the tanker as it overturned.
The same trucks that are essential to societal functioning can cause big problems. It sounds like there were some special circumstances in this case: the particular cargo of this truck – a flammable liquid – plus the location of the accident on a bridge within a region with a major river flowing through it with the accident occurring before evening rush hour. Change some of these variables – a less problematic cargo or a different location or an accident at 9 PM – and the problem would be less.
At the same time, it may be depressing for drivers that just one accident could cause such a ripple effect. Traffic flow throughout a vast region can be a complex enterprise with hundreds of thousands of vehicles of different kinds traveling on different kinds of roads. Accidents are bound to occur as are other possible events that could impede traffic flow (construction, police activity, weather, etc.). With so many moving parts, it may not take all that much for traffic to slow down and then that delay to ripple through time and geography.
Are there ways to build more resilient road systems? What could be done to prevent such occurrences? Having multiple road options could help though duplicating highway destinations can be difficult. Limiting what kinds of vehicles are on certain roads could cut down on more rare accidents (like this one). Having response teams that can quickly respond to and clear accidents helps. Autonomous vehicles might be an answer in the long run. Thinking more broadly, relying more on transportation options like trains that move more people at a time could the stress on roads.
All of this may not be terribly relevant to the driver sitting in traffic because of this truck crash. Yet, thinking about how to minimize such incidents in the future could have large payoffs in terms of recovered time and energy.