The current paper addresses the mobility and willingness to travel of robbery offenders. A five-sector robbery typology was constructed, consisting of: personal robbery, commercial robbery, carjacking robbery, home-invasion robbery, and robbery by sudden snatching. Defining mobility as the straight-line distance between the offender's home residence and the location of the robbery offense, the extent of criminal mobility for each type of robbery offense was analyzed. Using geographical information system (GIS) technologies and, more specifically, geocoding software programs, the latitudinal and longitudinal coordinates of the offender's home and offense's location was determined. It was found that a subset of robbery offenders exhibit relatively high mobility across all five robbery types. However, distinct mobility patterns also emerged between the different types of robbery offenses. Policy and research implications from these findings are discussed.

Research to date has demonstrated significant relationships between the presence of outdoor drug markets and violent crime. Scholars have neglected however, to consider the role of travel distance on the drugs/violence nexus. The current study examines whether features of the distributions of travel distance to markets of drug buyers, drug sellers, or the interaction between the two distributions predicts drug market violence levels net of surrounding community demographic structure. Reuter and MacCoun's (1992) as yet untested model about the connections between drugs and violent crime, predicts that the interaction of drug seller and buyer distance distributions from varying distances more powerfully drug market violence levels than buyer and average distance averages. This suggests that how the travel patterns of the two major participants in drug markets intersect is key to understanding differences. That model is tested here. In addition, for comparison purposes, impacts of buyer and seller travel median distances are modeled separately. This work uses 5 years (2006-2010) of incident and arrest data from the Philadelphia Police Department. Reuter and MacCoun's model will be tested using the following analytical techniques. First, a methodology for locating and bounding drug markets using a nearest neighbor, hierarchical clustering technique is introduced. Using this methodology 34 drug markets are identified. Second, hierarchical linear models examining buyers and sellers separately predict travel distances to drug markets. Arrestees are nested within markets. This technique separates influences on distance arising from arrestees from drug market distance differences. Third, how market level median travel distance affects within drug market violence is considered. Specifically, the main effects of median buyer travel distance and median seller travel distance on drug market violence are captured using separate Poisson hierarchical linear models. Finally, impacts of the interaction between buyer and seller distance, Reuter and MacCoun's (1992) focus, are explored in another series of generalized hierarchical linear models. The main findings from the dissertation are as follows: 1. Results provide partial support for Reuter and MacCoun's drug market-violence model using multiple operationalizations. Public markets--those in which buyers and sellers travel from outside their own neighborhoods--are expected to be the most violent. 2. Separate raw distance measures for buyers and sellers correlate with within-drug market violence, after controlling for community demographics. 3. A negative effect of socioeconomic status and violence holds even when modeled with drug market variables. 4. As the proportion of crack cocaine sales within drug markets increases so too does within-market violence. Conceptual implications highlight the need to investigate social ties as an intervening variable in the travel distance »» drug market violence relationship. It is not clear from this research whether the travel distances of drug offenders in some way explains the amount or strength of social ties in a drug market, which in turn serves to suppress or elevate within-drug market violence. Policy implications suggest that Reuter and MacCoun's drug market types may connect with specific policing responses. Policing efforts may not receive much support from community residents because dense social networks may discourage reporting illicit activity. Markets drawing dealers and customers from farther away, and located around commercial and recreational centers may be amenable to place-based policing initiatives and coordinated intervention strategies with multiple city agencies. / Criminal Justice

A minority of the research conducted on the geography of crime has considered crime as a vectored event, consisting of multiple locations of interest and straight-line connections between them. Within this small literature, very little attention has been paid to relationships between the various 'journey' vectors available for consideration. Recently several studies have resurrected the notion of Mobility Triangle Analysis as a method for examining crime as a multi-vectored event. The research described here illustrates that geometric configuration of multi-vector homicide events drives prior findings related to mobility triangle analyses, and demonstrates a two-stage method for reconciling this issue. In addition to examining the geometric configuration of homicide, the research also examines issues of orientation, extent, and the impact of contextual factors in multi-vector models of homicide geography. / Criminal Justice

Cette étude porte sur la distance parcourue pour commettre un crime à Gatineau en 2006. Peu d’études canadiennes récentes ont porté sur le sujet. De plus, il existe un vide de connaissances sur la mobilité des délinquants dans les petites villes et les banlieues. La présente recherche vise à comparer trois mesures de distance différentes, à vérifier si la distance parcourue varie en fonction du type de crime et à voir si les variables de temps (jour de la semaine, moment de la journée et saison) de même que certaines caractéristiques des suspects (âge, sexe et lieu de résidence) ont un impact sur la distance parcourue. Pour chaque crime, l’adresse du suspect et le lieu du crime ont été géocodées pour ensuite calculer la distance entre les deux points. Il ressort de l’analyse de la forme des courbes de distances que seules les agressions sexuelles présentent une zone tampon. Les résultats des analyses statistiques indiquent que les jeunes sont plus mobiles que les suspects plus âgés et que les hommes parcourent une distance plus élevée que les femmes. Étonnement, la distance parcourue ne diffère pas significativement selon la saison et le moment de la journée. Enfin, comparativement aux autres criminels, les délinquants qui ont commis un vol qualifié sont ceux qui ont parcouru les plus grandes distances. / This study focuses on the journey to crime of the offenders who have committed a crime in Gatineau in 2006. There are only a few recent Canadian studies on the subject. In addition there is a vacuum of knowledge on the journey to crime in smaller cities and suburbs. This research is designed to compare three different measures of distance, to check if the distance varies depending on the type of crime and see if the variables of time (day of week, time of day and season) as well as some characteristics of suspects (age, sex and place of residence) have an impact on the distance traveled. For each crime, the address of the suspect and the crime location were geocoded then, the distance between the two points was calculated. An analysis of the shapes curves pattern of the distances indicates that sexual assault is the only type of crime which possesses a buffer zone. The results of statistical analysis show that young people are more mobile than older suspects and that men travel a greater distance than women. Surprisingly, the distance does not differ significantly according to season and time of day. Finally, compared to the other criminal offenders, those who have committed a robbery traveled the greatest distances.

Cette étude porte sur la distance parcourue pour commettre un crime à Gatineau en 2006. Peu d’études canadiennes récentes ont porté sur le sujet. De plus, il existe un vide de connaissances sur la mobilité des délinquants dans les petites villes et les banlieues. La présente recherche vise à comparer trois mesures de distance différentes, à vérifier si la distance parcourue varie en fonction du type de crime et à voir si les variables de temps (jour de la semaine, moment de la journée et saison) de même que certaines caractéristiques des suspects (âge, sexe et lieu de résidence) ont un impact sur la distance parcourue. Pour chaque crime, l’adresse du suspect et le lieu du crime ont été géocodées pour ensuite calculer la distance entre les deux points. Il ressort de l’analyse de la forme des courbes de distances que seules les agressions sexuelles présentent une zone tampon. Les résultats des analyses statistiques indiquent que les jeunes sont plus mobiles que les suspects plus âgés et que les hommes parcourent une distance plus élevée que les femmes. Étonnement, la distance parcourue ne diffère pas significativement selon la saison et le moment de la journée. Enfin, comparativement aux autres criminels, les délinquants qui ont commis un vol qualifié sont ceux qui ont parcouru les plus grandes distances. / This study focuses on the journey to crime of the offenders who have committed a crime in Gatineau in 2006. There are only a few recent Canadian studies on the subject. In addition there is a vacuum of knowledge on the journey to crime in smaller cities and suburbs. This research is designed to compare three different measures of distance, to check if the distance varies depending on the type of crime and see if the variables of time (day of week, time of day and season) as well as some characteristics of suspects (age, sex and place of residence) have an impact on the distance traveled. For each crime, the address of the suspect and the crime location were geocoded then, the distance between the two points was calculated. An analysis of the shapes curves pattern of the distances indicates that sexual assault is the only type of crime which possesses a buffer zone. The results of statistical analysis show that young people are more mobile than older suspects and that men travel a greater distance than women. Surprisingly, the distance does not differ significantly according to season and time of day. Finally, compared to the other criminal offenders, those who have committed a robbery traveled the greatest distances.

Notre compréhension de la mobilité criminelle repose presque exclusivement sur des études sur le journey-to-crime qui portent sur l'analyse des distances parcourues par les délinquants entre leur domicile et le lieu de leurs crimes. Dans cette thèse, nous nous demandons d'abord si la pertinence théorique et la validité méthodologique sous-jacente à la mesure de journey-to-crime ont été suffisamment démontrées pour justifier son influence dominante dans le domaine de la criminologie environnementale. Sur la base d'une analyse critique des recherches sur le journey-to-crime, nous soutenons que si l'intérêt pour la mesure est compréhensible, il existe de meilleures façons de mesurer la mobilité criminelle. Nous démontrons que certains postulats implicites qui la sous-tendent sont trompeurs et que de nombreux biais méthodologiques limitent son utilité. Nous suggérons que pour mieux comprendre la mobilité criminelle, le journey-to-crime devrait devenir complémentaire à de nouvelles mesures plus raffinées. Des implications pour les études futures sont proposées. Nous quantifions ensuite de manière empirique les différents biais méthodologiques de la mesure de journey-to-crime en examinant dans quelle mesure ceux-ci affectent sa capacité à estimer le « véritable » trajet effectué par les délinquants lors de la perpétration de leurs crimes. À l'aide de données policières, d'entrevues et de technologies numériques de cartographie, l'itinéraire détaillé emprunté par 98 délinquants lors de 449 crimes de vol est reconstitué afin de tester certaines des hypothèses qui sous-tendent la mesure de journey-to-crime. Les données policières utilisées pour calculer les distances résidence-crime se sont révélées être suffisamment fiables au niveau du lieu du crime, mais peu fiables pour ce qui est du lieu de résidence du délinquant. Plusieurs raisons sont fournies pour expliquer pourquoi les policiers ont de la difficulté à identifier correctement où un délinquant réside réellement le jour d'un crime donné. La résidence des délinquants s'est distinguée comme un endroit important de leur parcours criminel, mais le trajet effectivement emprunté par ces derniers s'est avéré beaucoup plus complexe que l'itinéraire résidence-crime-résidence présumé par la mesure de journey-to-crime. Malgré ses nombreuses lacunes, nos résultats ont démontré que cette mesure pouvait quand même être considérée comme une estimation valide et utile de la distance totale réellement parcourue lors d'un crime par les auteurs de vols qualifiés et d'autres vols, mais pas par les auteurs de cambriolages et de vols de véhicule à moteur. Les implications pour la recherche sur la mobilité criminelle et les études futures sont abordées. Nous investiguons finalement le nomadisme criminel, soit la propension d'un individu à s'engager dans des déplacements interurbains continus ou intermittents comme moyen de faire face aux conséquences de son mode de vie criminel (p. ex., stigmatisation, pauvreté, désorganisation, etc.) et/ou comme stratégie d'adaptation à la réalité d'être un « criminel de carrière ». L'itinéraire des crimes commis au Canada pendant la carrière criminelle de 448 hommes reconnus coupables d'infractions sexuelles a été reconstitué grâce à des entrevues individuelles et à l'analyse détaillée de casiers judiciaires. Cinq composantes distinctes du nomadisme criminel (c.-à-d., nombre de trajets, nombre de points nodaux, longueur des routes, étendue géographique de la criminalité et superficie de la zone d'activité mesospatiale), inspirées de la théorie des patrons criminels (crime pattern theory), sont suggérées et analysées. Les résultats montrent que le nomadisme criminel est davantage la réalité de gens de race blanche, jeunes et éduqués, qui ont une carrière criminelle prolifique entrecoupée de longues peines d'incarcération. Les délinquants nomades n'errent pas au hasard, mais semblent plutôt chercher des opportunités et un retour à une certaine forme d'anonymat. Les variables relatives aux infractions sexuelles n'ont pas apporté une contribution significative aux modèles de prédiction, ce qui donne à penser que le nomadisme criminel est davantage un phénomène criminel général que spécifique aux infractions sexuelles. Nos résultats suggèrent qu'une carrière criminelle prolifique est généralement associée à un mode de vie nomade et géographiquement dispersé. Les implications pour les politiques publiques et les études futures sont abordées. / Our collective understanding of criminal mobility relies almost exclusively on journey-to-crime research, which focuses on the distances traveled by offenders from their homes to the location of their crimes. In this thesis, we first ask whether the theoretical relevance and the methodological validity underlying the journey-to-crime measurement are sufficient for it to continue to be a leading influence in the field of environmental criminology. Based on a critical review of the foundations of journey-to-crime research, we argue that while the interest in the journey-to-crime measurement is understandable, there are better ways to assess criminal mobility. Some likely misleading implicit presuppositions and methodological biases are identified, and the manner in which they affect our comprehension of criminal mobility is discussed. We suggest that a better understanding of criminal mobility would come from complementing journey-to-crime with new, more refined, measures. Implications for future studies are proposed. We then empirically quantify the methodological biases of the journey-to-crime measurement, by investigating the extent to which they affect its ability to estimate the itineraries offenders actually travel during the perpetration of their crimes. With the support of police-arrest records, interviews, and web-mapping technologies, the detailed route taken by 98 offenders during 449 theft-related crimes are reconstructed in order to test some of the key assumptions underlying journey-to-crime research. Police data used to compute home-crime distances have been found to provide satisfactorily accurate crime-location addresses, but poorly accurate offender home-addresses. Several explanations of why the police have problems correctly identifying where an offender is truly residing on the day of a given crime are presented. Even if the offender's residence was the most important node in their crime journey, the actual travel undertaken by offenders was much more complex than the home-crime-home itinerary assumed by the journey-to-crime measurement. Despite its numerous drawbacks, the traditional journey-to-crime measure is still a valid and useful proxy for the total distance actually traveled by offenders in robbery and “other theft”, but not in burglary and motor-vehicle theft. Implications for criminal mobility research and future studies are discussed. We finally investigate criminal nomadism ― an individual’s propensity to engage in continuous or intermittent interurban travel as a way to cope with the consequences of their criminal lifestyle (e.g., stigma, poverty, disorganization, etc.) and/or as a strategy to adapt to the reality of being a “career criminal.” The criminal-career itinerary across Canada of 448 men convicted of sex offenses was reconstructed through individual interviews and analysis of detailed criminal records. Five distinct components of criminal nomadism (i.e., trips, nodes, paths, range, and mesolevel activity space), inspired by crime pattern theory, are suggested and analyzed. Results show that criminal nomadism is the reality of young and educated Whites who have a prolific criminal career interspersed with long incarceration sentences. Nomadic offenders did not wander freely and randomly, but rather seemed to be looking for opportunities and privacy. Sex-offending variables did not make a significant contribution to predictions, suggesting that criminal nomadism is more a general offending phenomenon than something specific to sex offending. This provides supporting evidence for the hypothesis that an extensive criminal career is generally associated with a geographically scattered and nomadic lifestyle. Implications for public policies and future studies are discussed.