The total number of crimes on the Chicago Transit Authority (CTA) fell 25% during 2015, the fourth straight year that crimes have decreased on the system. Theft and robberies, the most common crimes, declined 19% and 22%, respectively, in 2015.

The CTA and the Chicago Police Department have deployed several strategies to fight crime on CTA buses, trains and at rail stations. Those include the expansion of the CTA’s extensive network of security cameras to more than 23,000, including multiple cameras on every CTA train and bus and at every CTA rail station. The City has also expanded police patrols, rail saturation missions and increased undercover operations.

Security camera images have significantly helped in identifying suspects and making arrests, and serve as a warning to would-be offenders. Last year, 256 individuals whose images were caught on CTA cameras were arrested for crimes committed on or near CTA property, an 8% increase over 2014. Those include a suspect who turned himself in voluntarily after police released images of him connected to an assault incident in December and the November arrest of a serial pickpocketer in at least 21 incidents between May and November.

Since 2011, the CTA has more than doubled the number of security cameras across the rail system, and undertaken a project to retrofit more than 250 older-series rail cars with interior cameras. All of the CTA’s newest 5000-series rail cars come equipped with cameras.

On CTA’s rail system, total crime fell 32% in 2015 from the previous year. Robberies dropped 19 percent while thefts fell 13% across trains, stations platforms and tracks. Total crimes on buses also declined by 32% in 2015. Robbery and theft decreased 31% and 36%, respectively, and are also at their lowest rates in the past four years.

Overall, serious crime (i.e. murder, criminal sexual assault, robbery, aggravated assault and battery, etc.) is very rare on CTA trains and buses, averaging seven incidents for every 10 million rides in 2015.

CTA also saw a significant drop — 72% — in the category of “fraud” or fare evasion — a result of the efforts CTA took last year to curtail the improper and unauthorized use of free- and reduced-fare ride cards.