While the subway offers a convenient and relatively inexpensive way of getting around major cities, it does have drawbacks as well as advantages. You must consider both the advantages and disadvantages of subway systems when deciding which form of transit to use, as ground-level transportation may be a better option for some people.
Subway trains make a lot of noise, not only when they are arriving and departing but also when they are idling on the tracks as passengers get on and off. In addition, passengers are exposed to dangerously high decibel levels during their ride, which in some cases can be even louder than the sounds they're exposed to on the plaforms. For example, researchers at Columbia University in 2006 found that passengers in New York subways had routine exposure to sounds in excess of 80 decibels. Over an extended period of time, this noise has the potential to permanently damage hearing.
In most cities, subway systems are used by tens of thousands of people every day and crowding is a real issue -- especially at peak times. People who get nervous or anxious when crowded in a tight space may prefer other forms of transportation, and overcrowded subway platforms create a major public danger. Researchers at the China Academy of Safety Science and Technology showed in a 2009 study that evacuation times for subway stations were dangerously high and that an emergency situation could lead to a high human death toll.
Pickpocketing, muggings and assaults occur in subway systems around the world. While closed-circuit cameras, security guards and a heavier police presence can combat these problems, the resources do not exist to outfit every subway station in a municipal system with these safeguards, leaving passengers vulnerable to these threats. In some major cities around the world, crime in subways continues to trend up, with many municipalities lacking the resources to beef up security and policing in their city's subway stations.
Spread of Diseases
Being in close proximity to other people and touching surfaces that thousands of other people touch during the course of a day can lead to the spread of bacteria and viruses. You can mitigate these risks by practicing proper hand sanitation, but even the most careful passenger can still pick up an infectious disease on the subway. A controlled Columbia University study in 2005 showed that people who travel in automobiles have a much lower risk of contracting an infectious disease than people who regularly take the subway.