While it is natural to think that more light always improves safety, that is not the case. Lighting which produces glare actually decreases safety by creating shadows which block vision.  

Further, research has shown that light in certain locations can actually increase crime levels.  

Glare Stop Sign

The lighting in this case produces glare and backlights the stop sign, making it difficult to see.

Glare and Intruder

The glare from the unshielded and intense light fixture makes the man standing in the gate invisible.  He can be seen only when the glare is shielded.  

Chicago Light and Crime Study

The Chicago Alley Lighting Project from 2000 was a research initiative conducted for the Illinois Criminal Justice Information Authority to determine if there was a link between light levels and crime.  The study increased lighting in alleys by upgrading fixtures from 90-watt bulbs to 250 watts.  Crimes in three categories were tracked before and after the lighting increase: violent offenses, property offenses, and non-indexed offenses.  

The data shows an increase in crime in all categories after the lighting was upgraded.  The control area with no change in lighting also reported an increase in crime in all categories, but at a smaller level - the control figure had a 19% increase, while the experimental area with the increased lighting had a 40% increase.      

There are several explanations for the greater increase in crime for the the experimental area with the increased lighting, but one overarching lesson is clear - increased lighting does not automatically lead to decreased crime levels.