The phenomena of increased road size increasing traffic congestion is known as "Induced Travel Demand" (ITD). In actuality, the additional lanes will just draw more vehicular traffic onto the motorway, causing long-term traffic congestion. However, during construction periods, the new lanes can help relieve some of the existing congestion.
In general, research has shown that ITD is true for most types of transportation infrastructure. Larger vehicles need more space to drive safely and predictably, which means they take up more room on the road. For this reason, large vehicles tend to create traffic jams when they enter an area where there are no wider lanes available to divide them from shorter vehicles.
Sometimes, traffic engineers design highways with variable speed limits to accommodate different types of traffic flows. For example, if a highway has two lanes in each direction and one lane is designated for fast travel while the other is designed for commuting, then it may be necessary to limit the speed in the high-use section to ensure enough space remains for emergencies.
Variable speed limits are also useful during special events like race weekends or concerts when traffic volumes are expected to increase dramatically for several hours. During these times, engineers may choose to remove some of the existing traffic signals on busy streets to allow drivers more time to react to the changes in direction and speed required by the event.
Congestion increases the cost and time of individuals, businesses, and the economy as a whole, as well as the stress level. The additional gasoline consumed, as well as the higher-than-necessary amount of vehicle emissions, contribute to the cost to people and society.
When there are too many cars for the amount of space available, clearing the streets might take a long time. As automobiles slow down, the route becomes increasingly crowded, a phenomenon known as a "traffic wave." When automobiles start accelerating in waves, the most crowded section of the road advances backwards down the line.
The most obvious reason for increased traffic congestion is population expansion. More people in an affluent country equals more automobiles. However, overall vehicle mileage traveled has increased significantly faster than population growth. Furthermore, road construction in the United States has trailed well behind growth in car travel. This means that additional roads are being built to handle current traffic levels or even higher volumes.
Another factor contributing to increased traffic is the growing use of vehicles as a mode of transportation. Many countries have large populations living in rural areas without access to public transportation. These people need cars to get to work and other places of interest. The more people drive alone, the more traffic there will be. This is called "individual driving" and it's becoming a major problem in developing countries where people want to improve their lives but lack the money for buses or trains.
At last, technology has been introduced into the equation. Cars now talk to each other via wireless networks called "ad-hoc groups". This allows drivers to communicate with each other and adjust traffic speeds. Some cars even beep when another driver approaches from behind!
These days, no one wants to live in a neighborhood with ugly houses next to busy streets. So developers are creating communities with shopping centers, restaurants, and other attractions within easy reach of their homes. People like the idea of walking to their favorite store, and they can do so safely since there's less traffic around these new buildings.
This means that the main cause of increased traffic congestion is the increasing number of vehicles on the road.
Other factors include changes in land use, transportation infrastructure improvements, and changing driver behavior. Land use changes affect how much area there is to drive through, where different types of buildings and facilities are located, etc. Transportation infrastructure improvements include building new roads, upgrading existing ones, and modifying traffic signals. Changing driver behavior includes such things as driving more often or longer distances at slower speeds.
Increasing numbers of cars on the road lead to greater congestion because there aren't enough hours in the day or enough miles along the road to go around. This is especially true during peak travel times like morning and evening rush hours and on weekends when many people are out and about looking for a place to go or something to do.
On any given day there are only so many lanes available on the road. If everyone tried to go straight down the middle of the lane, there wouldn't be enough room for all the other drivers to pass. So drivers move over to the right side of the lane to make room for the next car.
Drivers' Contribution to Traffic Every time a vehicle slows or accelerates, it impacts the flow of traffic around them. This flow then spreads to the other automobiles in the vicinity. Congestion occurs as a result of these bursts of slowing, which allow additional automobiles to access the route.
The more frequently vehicles slow down and speed up again, the more likely it is that they will be involved in a crash. This is because drivers have less time to react to changing conditions in their environment. For example, if another driver suddenly enters the intersection against a red light, this is a cue for you to stop, but by the time your brain registers the danger and sends out the appropriate signals, it may be too late to avoid an accident.
In addition to these mechanical factors, traffic jams are also caused by human behavior. People make mistakes while driving, such as speeding or failing to stop at a red light. These errors can cause other drivers to change their routes around the mistake, creating more delays for everyone else on the road.
Finally, some traffic jams are initiated by accidents blocking the road. In order to get to their destinations, people rely on public transportation, so when an accident blocks the route of a city bus, many more individuals are affected than would be otherwise. The need for alternative methods of travel causes traffic to build up behind the accident scene.