Police bicycle

A police bicycle is a land vehicle used by police departments, most commonly in the form of a mountain bicycle. They are designed to meet the requirements unique to each department.
The maneuverability of these vehicles on crowded sidewalks and their ability to navigate narrow, crowded driveways offer advantages over cars, although a bicycle's top speed is lower.
Bicycle patrols are more common in temperate urban areas where limited coverage areas are available. The use of bicycles instead of cars can make police officers more easily approachable, especially in low-crime areas. Bicycles can also be issued to police officers to enhance the mobility and range of foot patrols. Bicycles are also effective crime-fighting tools when used in densely populated urban areas. The bikes are nearly silent in operation and many criminals do not realize that an approaching person on a bike is actually a police officer. Furthermore, if the criminal attempts to flee on foot, the riding police officer has a speed advantage while able to quickly dismount if necessary.
In the average hour, a patrol car would have 3.3 contacts with the public, while bicycle patrols had 7.3 contacts with the public. The average number of people in contact with the police per hour was 10.5 for motor patrols and 22.8 for bicycle patrols. This information tells us simply that the activity level of police officers on bicycles is higher than that of the officers in cars.
History.
Police officers began bicycling late in the 19th century, with the first department adopting boneshakers in 1869 in Illinois. British officers began using tricycles by the 1880s, around the same time Boston, MA was patrolled by penny-farthings. Newark, NJ had established a bicycle squad in 1888. With the advent of the safety bicycle and the bike boom of the 1890s, police bicycles came into widespread use in North American cities. Bicycles began to see greater adoption by rural departments around the same time. The Kent police purchased 20 bicycles in 1896, and there were 129 rural police bicycle patrols were operating by 1904 . 
Some countries retained the police bicycle while others replaced them with motor vehicles. In the 21st century there has been renewed interest in police bicycles, since they provide greater accessibility to bicycle and pedestrian zones and allow access when roads are congested.
Bicycle characteristics.
The bicycles are custom designed for law enforcement use. Many manufacturers of bicycles offer police models, including Haro, Volcanic, Trek, Cannondale, Fuji, Safariland-Kona, Force, and KHS. Other companies offer police, fire and EMS specific models. Many are equipped with a rear rack and bag to hold equipment.
Police bicycles' pedals are almost always flat pedals, sometimes outfitted with toe clips/straps, to allow for normal shoes to be worn (versus cycling-specific shoes that clip into "clipless" pedals), allowing officers to chase on foot if necessary.
They are equipped with front and rear lighting systems, with a water bottle battery. The lights can be LED, or halogen, or sometimes Xenon strobes. A headlight(s) are on the front, along with red or blue flashing lights. In the UK emergency service bicycles were allowed blue flashing lights from 21 October 2005. A red light is often attached to the rear of the bike.
Tires are usually semi-slick designs with smooth centers for street riding and mild tread or knobs on the outer edges to provide some traction if the bikes are ridden off a paved surface.
The National Institute for Occupational Safety and Health (NIOSH) has investigated the potential health effects of prolonged bicycling in police bicycle patrol units, including the possibility that some bicycle saddles exert excessive pressure on the urogenital area of cyclists, restricting blood flow to the genitals. NIOSH recommends that riders use a no-nose bicycle seat for workplace bicycling. In contrast, cycling expert Grant Petersen asserts that most modern saddles are designed to avoid excessive pressure on the urogenital area and that noseless saddles result in diminished bicycle handling capabilities.
Specialized training for modern bicycle officers is provided by companies and professional organizations. American Bike Patrol Services is one of the first training organizations serving law enforcement in conjunction with Californias academies training programs since 1991. The Law Enforcement Bicycling Association (LEBA) was founded by members of the first police mountain bike patrol in the U.S. and began training colleagues from across North America in the early 1990s. With roots in John Forester's Effective Cycling and the League of American Bicyclists, the International Police Mountain Bike Association provides training courses for officers and hosts an annual professional conference called Police On Bikes. Common training topics include nutrition, clothing and protective equipment, bike maintenance and repair, prevention of accidents and common injuries, slow speed balance and handling, technical maneuvers, night operations, bike and patrol equipment, firearms training, patrol tactics, and unit-level formations and crowd control techniques. 
References.
 14. "ABPS" American Bike Patrol Services. Police training courses, 2020.