How Traffic Works

How Traffic Works

How many hours have you spent sitting in bumper-to-bumper traffic? According to the Texas Transportation Institute (TTI) at Texas A&M University, you may spend up to two weeks every year in your automobile [source: Reason Foundation].

Each year, drivers in 28 urban regions, including Boston, Detroit, Atlanta, San Francisco, Orlando, and Minneapolis-St. Paul, spent a full work week stuck in traffic, according to a 2007 study. In Los Angeles, the most congested city in the nation, it might take up to two weeks.

Not simply your health is negatively affected by traffic congestion. The projected cost of traffic in 2005 was more than $78 billion (in fuel and lost time), not including environmental damage or health costs due to pollution [source: TTI]. In fact, Americans purchased an additional 2,9 billion gallons of gasoline due to traffic congestion. The annual average cost for a single driver was $710 [source: TTI].

The most fundamental explanation for traffic congestion is that the number of motorists attempting to utilize the same road exceeds the road’s capacity to accommodate automobiles. This is a really straightforward explanation: too many cars in one location produce congestion. Sadly, the underlying causes of too many automobiles in one location are more complex. University departments and civil engineers invest countless hours and millions of money to comprehend how traffic congestion develops and what can be done to alleviate it.

The actions of city planners, civil engineers, environmental advocacy groups, homeowner associations, politicians, and the general populace can have a substantial impact on how we solve traffic congestion. Traffic is a highly political and sensitive subject due to the high cost of practically every proposed solution, which raises the question of who foots the bill.

This article will discuss traffic congestion on highways and surface streets, as well as the traffic management methods available to city and state officials. We will examine ways in which you can help prevent traffic jams through your personal driving and car maintenance practices. In the final segment, we will identify the cities with the worst traffic.

In the following section, we will examine highway congestion in further detail.

Traffic Causes

You cannot comprehend how a five-lane motorway can become so congested. It seems as though every vehicle in the city has joined you on the freeway at once. Whenever movement occurs, traffic moves at a snail’s pace. You are compelled to spend time, money, and gas. What is the cause?

When the first vehicle stops, all subsequent vehicles must also stop. Even when the initial car begins to proceed again, further incoming cars must halt farther down the road, and the crowded region moves backwards in a wave until traffic becomes light enough to dissipate.
Assuming construction, accidents, and stuck vehicles are not to fault, it is probable because more cars are entering the roadway than exiting. As additional vehicles enter a congested road, drivers are forced to use their brakes to avoid collisions, so generating a traffic wave. Along with a domino effect, a traffic wave arises as cars slow down and the tendency continues backward. As long as there are more vehicles approaching from behind, traffic will move in waves.

In general, there are two basic categories of traffic contributors: network overload and traffic disturbances.

Network overload

Regardless of the actual road conditions, if there are motorways or surface streets with considerable traffic congestion, they fall under the category of network overload. These are the chokepoints and traffic jams where demand consistently exceeds capacity.

As room becomes available in front of your vehicle, you can accelerate to escape the congestion. The driver behind you can accelerate a few seconds later, followed by the driver behind them a few seconds later. The congestion does not immediately dissipate; it continues to shift back down the highway at a snail’s pace. If traffic gets light enough to eliminate the traffic-wave effect, congestion can be alleviated.

Traffic Disturbances

How Traffic Works

Accidents and mechanical failures, road construction and maintenance, and severe weather conditions are all considered traffic disturbances. You cannot always foresee where these disruptions will occur, but they have a significant impact on traffic flow anyway.

It is simple to envisage construction, an accident, or a police officer issuing a traffic ticket producing congestion — drivers slow down to change lanes or rubberneck to observe what occurred. Depending on the scope of the roadwork, one or more lanes may be closed, prompting traffic to switch to open but congested lanes. Due to safety concerns, bad weather could prompt some motorists to maintain a slower speed. According to the 2007 Urban Mobility Report from the Texas Transportation Institute, between 52 and 58 percent of vehicle delays are caused by traffic incidents [source: TTI].

In the following section, we will study cities and highway traffic.

Traffic Solutions

Numerous cities, including Los Angeles, have sophisticated traffic communications systems that inform drivers to changing road conditions, allowing them time to make decisions. Many municipalities have committed millions of dollars so that road maintenance can reach issue regions quickly.

There are several ways in which cities can combat highway congestion:

  • Cars are only permitted to enter the highway at predetermined intervals. This is accomplished by installing a signal-like light at the end of the ramp. Cities implementing ramp metering claim an annual reduction in travel delays of 29.4 million hours and a considerable decrease in traffic accidents, while highway capacity increased when ramp metering was implemented [source: TTI]. The Minnesota Department of Transportation implemented a stringent ramp-metering scheme with 430 ramp meters. In 2000, the DOT disabled ramp meters for seven weeks as an experiment. Over same time period, road accidents rose by 26%. After the experiment, the DOT reinstated ramp meters and saw a 14 percent boost in highway capacity [source: TTI]. Despite ramp metering can boost highway speeds while reducing accidents, it often takes a long time to deploy and requires a thorough investigation to ensure that surface street traffic isn’t impacted by automobiles backing up into the highway [source: AGC of America].
  • Many cities have installed HOV lanes (high-occupancy vehicle lanes) on highways. HOV lanes are intended for vehicles having a minimum number of occupants (usually two or three people per car). There is an incentive for drivers to carpool, thereby lowering the number of cars on the road. Some HOV lanes have dedicated exits, reducing the need to join with normal traffic.
  • Increasing lanes – a frequent method for alleviating traffic congestion is to add lanes to a highway by extending the road, narrowing existing lanes, or converting a shoulder or other space into a lane. These modifications are costly, time-consuming, and controversial. According to a number of studies, enlarging a road’s width has little effect on traffic congestion, as it merely increases the number of vehicles. Additional studies indicate that in many instances, road widening can significantly reduce traffic congestion. According to comprehensive study conducted by TTI, expanding lanes and widening roads is only effective if capacity increases faster than population [source: TTI].

Traffic Control

Most congestion reports center on highways, but surface streets can also be problematic, especially as suburban populations grow.

While planning surface streets, civil engineers must take a variety of elements into account. A badly constructed intersection, for instance, may be inconvenient or unsafe. Examine the various factors that a civil engineer must consider, including a driver’s line of sight, the influence of the intersection on the adjacent streets, the expected volume of traffic at the crossroads, and other difficulties.

Suburban sprawl is a further obstacle; once sparsely populated areas may undergo a population boom accompanied by new road design requirements.

Most cities have a well-established road network, making significant alterations hard or impossible. It is simple to offer remedies to a city’s traffic problems, but implementing them might be prohibitively costly. Traffic lights are maybe the easiest way to influence city traffic.

Typically, traffic lights are timed, sensor-based, or a combination of the two. Timed systems adhere to a predetermined schedule regardless of traffic circumstances (though the schedule itself might change throughout the day). As automobiles approach the intersection, sensor systems detect them and trigger a change in the traffic light. Advanced traffic control systems transmit signals to a central computer. A good system employs signals that are coordinated so that traffic flow is as steady as feasible. Nonetheless, even a well-designed traffic coordination system will only minimize traffic delay by about 1 percent [source:TTI].

Implementing turn bans and auto-restricted zones is another method of controlling traffic dispersion within a city. Turn bans prevent turning at particular crossroads or places on a road, diverting traffic to alternative routes. Auto-restricted zones are locations where automobiles are prohibited, typically to facilitate pedestrian traffic or preserve a city’s historic quarter. In Boston, for instance, you can locate the Downtown Crossing Project, a 12-block auto-restricted zone [source: TTI].

Congestion pricing, according to traffic experts such as British Secretary of State for Trade and Industry Alistair Darling, is the most effective method for alleviating congestion on motorways and surface streets. His view is that drivers impose a cost on a road (via wear and tear and environmental effect) and that they should pay a fee to offset that cost. In other words, driving on city streets would cost money. Similar to the notion of toll roads, but a bit more complex.

A true congestion pricing scheme would employ an electronic system of sensors to monitor each car as he navigated metropolitan streets. Each automobile would have a unique electronic identifier, comparable to a radio frequency identification tag. Prices may fluctuate throughout the day, typically hitting their peak during rush hour. A fine is incurred for driving on city streets within this time period. Although there are currently no congestion-pricing systems, there are no precise rates or fine-collection procedures to speak about. Opponents of congestion-pricing schemes assert that such a system would likely be politically impossible because motorists have become accustomed to driving for free on city streets. A comparable scheme in Seoul, South Korea was met with enormous public criticism, including accusations that the city was taxing cars [source: IGES].

Traffic-jam Prevention

How Traffic Works

If you wish to lessen your contribution to traffic congestion, you need first maintain your vehicle. Maintaining your vehicle properly might help prevent breakdowns on the road. Regular maintenance include of oil changes, tune-ups, and tire care. Maintain the correct tire pressure — it’s safer and can boost your fuel economy by up to 3,3 percent [source:]. Maintaining your vehicle will save you time and money, and may even help you avoid risky circumstances.

Maintain a safe and steady space between you and the driver in front of you on the road. Quickly accelerating and then decelerating causes drivers behind you to do the same, eventually leading in a wave of gridlock (and road anger!).

In an article titled “Vision of Congestion-Free Road Traffic and Cooperating Items,” Ricardo Morla suggests that we consider automobiles as occupying virtual slots. Each virtual slot occupies a physical location that moves at a constant speed down the route. As vehicles approach one another, their speeds must be adjusted so that the virtual spaces do not overlap. Morla acknowledges that this approach fails if there are more vehicles on a roadway than the virtual slots can accommodate. Yet, by maintaining a safe distance from other vehicles, you can assist reduce congestion [source: Morla].

Driving during non-peak rush hours is yet another effective technique to avoid adding to the congestion issue. If your schedule is flexible, you can travel at off-peak hours. Proponents of the congestion-pricing system argue that charging cars during rush hour would encourage them to drive during off-peak hours. Opponents point out that this is akin to regressive taxation, which means that the majority of the cost is borne by the poor. They claim that those with flexible schedules are typically white-collar professionals, whereas those in lower-paying employment have set hours and are unable to avoid traffic. The fee would be paid by those who are least able to afford it [source: Arnott].

If you live near folks who work nearby, carpooling is an excellent choice. There are HOV lanes in the majority of cities, and carpooling reduces environmental stress and pollution. Many individuals are reluctant to give up the independence that comes with driving their own vehicle. Carpooling entails coordinating your schedule with others and planning any errands or side trips for when you get home.

If your city has a reliable public transit system, you can always utilize it to decrease your influence on traffic. Using public transit, like carpooling, requires sacrificing some independence and flexibility.

Worst Cities for Traffic

Los Angeles ranks first on the Texas Transportation Institute’s (TTI) list of cities with the worst traffic in the United States. Films, television shows, and songs have all made fun of the traffic problems in Los Angeles. Yet contrary to what you may have heard from the television show “24,” you cannot travel everywhere in Los Angeles within 15 minutes. In reality, Los Angeles’ travel time index is 1.92, indicating that a drive during peak hours will take nearly twice as long as during off-peak hours [source: TTI].

According to the 2000 Census, around 81% of all commuters travel to work by vehicle, truck, or van. About 66 percent of this demographic drove alone, while just 14.7% carpooled. The number of employees was 1,494,895. The majority of drivers traveled during peak hours. The average Los Angeles driver spends 72 hours per year stuck in traffic [source: TTI]; Los Angeles is the city that wastes the most time sitting in traffic. It equates to nearly two full weeks of looking at the driver in front of you and battling road rage.

Completing TTI’s ranking of the top five cities are the following:

Five of the twelve areas with the worst traffic congestion are in California. The majority of experts believe that congestion will continue to worsen as populations expand. Several places, such as Boston and New York City, are surprisingly absent from the list.

Some of these communities are examining innovative land-use strategies, building bike- and pedestrian-friendly high-density commerce and residential districts. Ideally, these communities will encourage individuals to travel without driving. Regrettably, this is unlikely to aid in short-term problem resolution. For these communities to have a significant impact on traffic congestion in the future, they must be vigilant and willing to make modifications.

Eliminating traffic congestion demands difficult and perhaps unpleasant decisions at all levels of government and among drivers. When the problem worsens, government officials will certainly scrutinize their decisions more closely. As awful as traffic is in the United States, it is significantly worse in other countries. There is little doubt that American policymakers will observe what occurs in other cities to determine what may work in the U.S.

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