Philadelphia boasts more residents commuting by bicycle per capita than any of the 10 other biggest cities in the United States. As you affix your ankle reflectors for this year's National Bike to Work Week (May 15-19), consider Philadelphia's connections to the two-wheeler.

Taking a broad definition of the term, the first "bicycle" in Pennsylvania emerged in 1819 from the parts of a threshing machine. A Germantown blacksmith fashioned it at the behest of artist and antiquarian Charles Willson Peale.

Technically a French-invented velocipede (Latin for "swift foot"), the 55-pound juggernaut lacked such luxuries as pedals and brakes. Riders would propel themselves with their feet on the ground, Flintstones-style.

At nearly 80 years old, Peale witnessed his children traveling – downhill, at least – "like the very devil," with "a swiftness that dazzles the sight."

The mechanical oddity – which Peale also put on display in his museum – initially captivated Philadelphians. This popular sentiment soon deflated.

The same year that Peale acquired his velocipede, the city issued its first citation for riding on the sidewalks, a spoke-stopping $3 fine.

The tenuous relationship among bicyclists, pedestrians, and other road users has been around since the very beginning.

Interest in the "wheel" briefly resurged with the 1876 Centennial Exhibition. Among the varied exhibits was the British-designed "ordinary," a bicycle with an extraordinarily large front wheel and a dinner-plate-sized rear wheel.

Even as these machines became more widely available, bicycling was not for the faint of heart. Riding demanded constant vigilance to avoid wagon wheel ruts, erratic ungulates, and edgy pedestrians crowding the primarily dirt and gravel roads.

"It is not always wise to dismount at once," advised an 1888 Philadelphia Bicycle Club bulletin. "To dismount suddenly is more likely to frighten a horse than continuing to ride slowly by, speaking to the horse as you do. Foot passengers on the road should not be needlessly shouted at, but should always be given a good wide berth."

Still good advice in 2017.

While the "ordinary" provided a much more controlled and enjoyable ride than its velocipede forebear, the machine remained extraordinarily unsafe due to the high center of gravity required of its riders. "Taking a header" by vaulting headfirst over the handlebars was a common accident befalling non-helmeted operators.

Philadelphia shifted into its first true bike boom in the 1890s after such innovations as chain-drive transmissions, pneumatic tires, and reduced height. These new "safety" machines resemble what we now recognize as the modern bicycle.

With a marked decrease in the chances of cracking one's cranium and a smaller price tag, these "safeties" provided a variety of riders — professionals, laborers, men, women — with a democratic means of travel, recreation, and sport.

For a sense of the bicycle's popularity, consider that the Inquirer regularly published a series of routes, complete with a hand-drawn map and a coupon offering discounts on hotels and restaurants along the way. In the realm of competitive cycling, professionals competed for purses five times greater than the highest baseball player's salary.

While the safety bicycle lived up to its name in many ways, the region's dilapidated road network continued to pose great challenges to commuting bicyclists.

To smooth out the city's rutted roads, the Associated Cycling Clubs of Philadelphia published "Improvement of City Streets" and "Highway Improvement" in support of bicycle-friendly infrastructure projects, including macadamized surfaces. Fairmount Park commissioners found on their desks petitions in favor of constructing bicycle paths as early as 1897.

The machine's popularity waned in tandem with the growing affordability of the automobile in the years leading up to the Second World War. Many of the improved road surfaces that allowed for cars' popularity, however, are traceable to the efforts of the city's bicyclists.

During the environmental activism of the 1970s — marked by an increased concern over pollution produced by gas-guzzling four-wheelers — bicyclists formed what is now the Bicycle Coalition of Greater Philadelphia. The coalition campaigned for funding of bicycle infrastructure, sponsored citywide rides, and published the Commuters' Bike Map for Philadelphia. The city's first bike lanes appeared in the 1990s along a half-mile stretch of Delaware Avenue.

Since the year 2000, interest in two-wheeled commuting continued to grow. Buffered lanes on the east-west arteries of Spruce and Pine Streets emerged in 2009. The Indego bike-share program, launched in 2015, generating a larger ridership in its first year than similar programs in Boston, Washington, and Denver.

In a 2016 survey conducted by Bicycling, the world's leading cycling magazine, Philadelphia ranked as the 15th most bike-friendly city in the country, the culmination of a trend stretching back nearly 200 years to Charles Willson Peale and his children.

Vincent Fraley is communications manager for the Historical Society of Pennsylvania.