Begun in October of 1998, the first part of the plan sought to upgrade and improve the city's 175,000 streetlights, which illuminate the arterial and residential streets. The second part of the plan involved repairing and upgrading the lighting in and around viaducts and Chicago Transit Authority stations. The final part of the plan has been to boost lighting levels in alleys across the city as a tool for public safety and fighting crime. In the past, 90-watt lights illuminated most city alleys; alley lighting levels have been increased by installing new fixtures that can accommodate 250-watt bulbs. The Illinois Criminal Justice Information Authority undertook an evaluation to assess the impact of increased alley lighting on crime rates in two eight-square-block areas, with emphasis on crimes that were most likely to have occurred in alleys. The evaluation first examined change in the experimental area that received increased alley lighting over a 1-year period prior to increased alley lighting and a 1-year period thereafter. Next, change over a 6-month period before and after increased alley lighting was examined for both the experimental area and the control area. The evaluation found that reported offenses increased between the 1-year preinstallation and 1-year postinstallation study period in the experimental area where alley lighting was improved. The evaluation also found that the experimental area experienced more notable increases in reported incidents over a 6-month preinstallation and 6-month postinstallation study period compared to the control area. The evaluation could not provide a definitive explanation of these findings. 15 figures and 17 references