Chief Gunn retired because of ill health in 1913. Garrett J.Farrell was appointed to succeed him as Chief of Police.
In December of 1913 the new Gamewell police callbox system with flashing lights for notifying officers they were needed was put into operation. The new callboxes were a success. In his 1914 annual report Chief Farrell commented about the system: It has exceeded all expectations. The red lights have been a grand success and we are able to get in communication with an officer within a few minutes when wanted for any call whatever. The officers reported once an hour from the boxes and if needed, they were notified of any complaint that needs attention." The chief asked for ten more boxes equipped with lights.
In 1915 the force was increased to a total of 146 patrolmen. During the same year the department started using the fingerprint system which added much to the efficiency of the Detective Bureau. One growing police problem in the city of Hartford was the increase of vehicular traffic which was growing so rapidly that the streets were becoming dangerous for pedestrians. In 1916 there were 396 traffic accidents recorded, resulting in the injury of 208 persons. In an effort to address problems of vice and immorality in the city in 1917, Officer P.B. Gavin was assigned special duty to investigate complaints related to prostitution. Officer Gavin made 216 arrests in only a few months.
In spite of the assignment of 14 officers to traffic duty in 1917, the number of traffic related injuries rose to 992 that year. The problem was brought under control in part by the addition of several motorcycle officers to regulate traffic.
The United States entered World War I on April 6, 1917. By 1918 the Supernumerary force in Hartford was decreased to 48 men. At the time most men in Hartford were directly involved in the war effort or employed in related jobs which were higher in pay than the supernumerary positions.
In 1917 the department started issuing a bulletin with all the complaints of the day for all officers as they went on duty. The bulletin also contained a training component which addressed state laws, city ordinances and requirements from the police manual. The purpose of the bulletin was to bring the officers to a higher standard of efficiency.
On November 28, 1919, Officer Thomas M. Knevet was struck and killed by an automobile. He was the first officer killed in the line of duty in the history of the department. Officer Knevet, who had 44 years of service with the Hartford Police Department when he was killed, was recognized by the National Law Enforcement Memorial in Washington D.C. in 1994 as having had the longest record of continuous service with a single law enforcement agency of any officer reported killed in the line of duty in the United States.
In 1919 185 cars were reported stolen in the city. Although about 75% of the stolen cars were later recovered, auto theft was becoming a police problem. Another related problem was the increasing number of incidents in which automobiles were used in the commission of crimes.
By the end of 1919 a new police precinct, precinct #1, located at 760 Capitol Avenue, had almost been completed. This precinct was created to increase the efficiency of the department. With the opening of the new precinct building officers would not have to travel as far to get to their beats. The next stage of this plan was to create a second precinct in the north end of the city as well.
On January 4, 1922 the Hartford Police Drill School was officially opened. The drill school was created to provide regular physical and mental training for regular and supernumerary members of the department. A short time after the drill school was started, all applicants for appointment to the police force were required to qualify by attaining a satisfactory average at the school. Members who were on the department for five years or less were required to attend the school for in-service training. All members of the department were trained in first aid and firearms.
In February 1927, Margaret Sanford was appointed as the first policewoman in the history of the Hartford Police Department. According to a newspaper article at the time, there was great community support to have a policewoman appointed to the force.
By 1930 the police department improved delivery of services by using cars to patrol beats in the residential districts. Because some of the outlying areas of the city were so spread out it became almost impossible for officers on foot to render efficient service.
On June 8, 1932, a second precinct was opened at 151 Vine Street. The city purchased an existing building and the land at that address for use as an additional precinct. A total of 52 members of the police department moved from headquarters to the new precinct. This move relieved the congested conditions at headquarters and provided more efficient police service to the north end of the city.
Another historic change in the Hartford Police Department's delivery of services took place on April 6, l936. On that date the Police Department started using radio patrols. The police roster and patrol areas were significantly changed with the advent of radio-equipped patrol cars. Initially, under this new plan, the city was divided into 13 districts each covered by a radio- equipped patrol car. Two officers were assigned to each radio car. In addition to around-the-clock radio car coverage, there were up to thirty footbeats on each shift. At the time there were 241 patrolmen in the department, seventy-two were assigned to radio cars, and eighty-six were assigned to footbeats. Forty-two of the remaining patrolmen were assigned to fixed traffic posts and six were assigned as ambulance and patrol wagon drivers. Four were assigned to the vice and liquor squad and three were detailed as radio dispatchers.
A natural disaster remembered as the great flood of 1936 struck Hartford in the latter part of March 1936. The Connecticut River reached historic heights. Telephone and power systems were crippled and the city was in darkness for almost a week. Members of the police department were required to work double shifts and the Connecticut National Guard and Naval Militia were called into service to work in conjunction with the Police to prevent looting. According to Chief Farrell's annual report in 1936, "the situation was kept well in hand and there was no looting."
In 1938 the practice of assigning two men to each patrol car was discontinued with the exception of those officers assigned to investigative work. This change made several officers available for foot patrol duty.
In September of 1938 another natural disaster, a flood and hurricane emergency struck the Hartford area. The Hartford Police, working hand in hand with the Connecticut National Guard and other military, units labored long hours under adverse conditions. According to the Chief's annual report, "... this duty was carried out with loyalty, patience and fortitude, and law and order was preserved."
The Hartford Police motor vehicle fleet in 1939 consisted of one 1936 Ford police patrol wagon, one 1930 GMC police patrol wagon, one 1936 Ford four door sedan, two 1937 Ford four door sedans, twelve 1937 Ford two door sedans, three 1938 Ford two door sedans, one 1936 Ford Service Truck, and seven Harley Davidson motorcycles.