Changing the physical design of an area has been long understood to be an effective way to change people's behavior. Within the field of criminology, Crime Prevention Through Environmental Design (CPTED) is an approach that alters the physical environment to decrease opportunities for crime. This dissertation examines two common tools used to reduce opportunities for crime: door locks and outdoor lighting. Though these tools are ubiquitously used, there are limitations in the current research on what effect these tools have on crime. This dissertation uses three papers to extend the CPTED literature by filling in some of these gaps in knowledge. The first paper assesses the effect of installing smart locks on the exterior doors of campus buildings on a major urban university campus. Results show that there is no significant change in the number of crimes per month on buildings that install these locks relative to a comparison group. The second paper measures how the number of outdoor, nighttime crimes change as the amount of moonlight - a relatively dim source of light - changes. Results show that nights with more moonlight have more crime, a finding in contrast to much of the literature on lighting. This suggests that the effects of lighting are non-linear - that a small increase of lighting may increase crime while significant increases in lighting decrease crime. The final paper evaluates one possible mechanism for the bulk of the lighting literature's finding that lighting decreases crime: that more light increases the risk of detection. This study uses the change in evening lighting when the United States transitions to (from) daylight saving time in spring (fall) which causes the evening the gain (lose) an hour of daylight. Results show that when evenings are brighter, the odds of an arrest for violent crimes - and for robbery in particular - significantly increase. Together, these studies advance the field of criminology by providing evidence on the effectiveness of two widely utilized crime control tools - door locks and outdoor lighting - to affect criminal behavior. This contribution can assist both researchers in the CPTED field as well as policy makers who must decide whether - and in which situations - to use door locks or outdoor lighting as crime control measures.