While crowding is hardly a new problem in the city, the sidewalks that cemented New York’s reputation as a world-class walking city have become obstacle courses as more people than ever live and work in the city and tourism surges. The problem is particularly acute in Manhattan. Around Penn Station and the Port Authority Bus Terminal, two of the city’s main transit hubs, commuters clutching coffee cups and briefcases squeeze by one another during the morning and evening rushes. Throngs of shoppers and visitors sometimes bring swaths of Lower Manhattan to a standstill, prompting some local residents to cite clogged sidewalks as their biggest problem in a recent community survey.

Foot traffic has slowed to a shuffle along some of the city’s most famous corridors. On Fifth Avenue, between 54th and 55th Streets, 26,831 pedestrians — enough to fill Madison Square Garden and Radio City Music Hall combined — passed through in three hours on a weekday in May 2015, up from 20,639 the year before, according to city data.

Transportation officials are taking measures to alleviate the congestion. To help accommodate foot traffic, they are adding more pedestrian plazas across the city, expanding the presence of a streetscape feature first embraced by the administration of Mayor Michael R. Bloomberg. One is scheduled to open soon on 33rd Street near Penn Station. There are also plans to widen a half-dozen sidewalks in Flushing, Queens, in the next year (the city’s sidewalks vary in width, but must be at least five feet wide).

While a crowded sidewalk is simply a symptom of a crowded city, it resonates deeply because it affects almost everyone. Unlike overstuffed subways or tourist attractions like, say, Times Square, there is no going around the sidewalks. They are to New York what freeways are to Los Angeles: an essential part of the infrastructure. Sidewalks not only get people from Point A to Point B, but also serve as a shared public space for rich and poor, native and tourist alike.