A distinction must be made between crimes facilitated by overcrowding and by lack of supervision. Both are caused by financial constraints and affect all forms of public transport. They result in too little space for passengers at busy periods and not enough staff to supervise vehicles and facilities at other times. Many successful measures have been reported in dealing with specific crimes. Much crime can be "designed out" of new subway systems and older train and bus stations and order maintenance may be an effective transit policing strategy. Research has been less successful in determining whether transit systems spread crime from high to lower crime areas and whether some transit systems and forms of transport are much less safe than others. Further, little success in deliberately reducing fear has been achieved. Security challenges presented by new light rail systems and forms of taxi service may not differ greatly from those encountered at present. Public transport in urban environments is discussed, and specific methods for preventing certain types of public transport crimes are outlined. Key security issues in public transport planning are addressed that pertain to victimization risks, mass transit and the distribution of crime, and fear of crime and rider-ship. Appendixes provide supplemental information on opportunity-reducing techniques of situational crime prevention for use in urban public transport systems and design features to prevent crime in the District of Columbia's Metro system. 193 references, 19 footnotes, 2 tables, and 3 figures