Traffic studies, security style

May 1, 1999 12:00 PM, JOHN M. FLANAGAN, CPP

You see them at highway intersections, sitting on canvas chairs with clipboards on their laps, watching cars pass by. They are conducting traffic studies seeking valuable data to improve the efficiency of highways, traffic lights, signage and lane layout.In the world of security, traffic studies also can be valuable. In much the same manner, barriers used for access control can be monitored; the "traffic" studied may be either people or vehicles. The resulting studies can help improve efficiency of identity authentication devices, policies, procedures and security officers.

What traffic studies accomplishAccess control traffic studies involve comprehensive surveys of barriers, including doors, gates and turnstiles. The surveys yield reports that outline survey results and conclusions on system conditions. They recommend changes, if needed, and reveal information about access control systems that otherwise might go undetected.Conclusions can quantify system capacities to indicate a need for more equipment or employees, or can describe strong points.

If changes are necessary, the report suggests how to implement barrier redesigns, repairs or changes in staff size. The reports also may be used to improve other access control barriers. Access control at barriers is the process through which most people come in direct contact with an enterprise's security program. Their impression of the contact is a major factor in the formation of attitudes about the security program. A speedy, "transparent" - but effectively restricted - passage promotes respect. A passage plagued by delays and complications has the opposite effect.

Best candidatesfor traffic studiesA traffic study conducted shortly after construction can detect problems before they become major. On the other hand, older barriers that may have functioned perfectly at one time may now be a detriment. Barriers with a history of problems should be evaluated for mechanical or electrical problems.Here are the best candidates and times for traffic studies:- New or old access control barriers with high pedestrian or vehicle traffic. - When the number of personnel or vehicles passing through a barrier changes radically. - When there are problems with speed of operation. The system may be unable to provide adequate control at the barrier being considered, evident when people tailgate behind others or circumvent barriers. In the case of old barriers, recent building codes may be making them obsolete due to lack of egress capacity.

Throughput is keyStudies reveal access control system capacity - the amount of traffic that can be handled without unacceptable delays or breeches. Capacity will be indicated by the term "throughput," used by systems analysts to describe system speed.Throughput has a quantity component as well as a time component. "Vehicles per hour," "people per hour," or "transactions per minute" are expressions of throughput. Figure 1 shows the number of people passing through a barrier in a lobby of a high-rise building during each hour of a shift.

Access control systems process by passing or blocking traffic moving in both directions. Exiting is an aspect not recorded by most access control computer programs. However, exiting adds to the throughput of the access control system. Also affecting throughput are deliveries, visitors and package inspections. Figure 2 shows the quantity of such activities during a 24-hour period at a data processing facility.

Other factors affect access control system capacity and are considered in traffic studies. The processing speed of identity authentication is a factor, involving devices for reading credentials and looking up electronic records. Other factors include the agility of a barrier needing to be moved or unlatched, the nature of the pathways leading to and from a barrier, and security personnel.

Avoid conflict-of-interestQualified outsiders should perform access control traffic studies to avoid conflict of interest relating to the outcome of the study. Independent security consultants - not employed by equipment vendors - and security managers from other facilities are ideal candidates for such work.The number of people required for the study will be determined by the estimated maximum number of people passing through the system at peak times. A thousand people per hour is about the maximum number one person can count, since all incidents related to the system must be recorded simultaneously.

Planning is importantAccess control traffic studies should include all aspects of the system, including all times the system is in operation: days, nights, weekends, holidays - not just starting and quitting times. Also, traffic must be studied during stressful times.Valentines Day, for example, can bring hundreds of flower and gift deliveries to a security area. Each delivery person must be dealt with, and, in some venues, each package must be inspected. Studies can be performed during fire or disaster drills, both of which strain access control to its limits. Conduct of traffic study should be comprehensiveBegin the study with a review of facility drawings for use in analyses and reporting. Photograph each barrier. Next, if system printouts are available, review for anomalies.Interview people involved, including employees, supervisors and guards assigned to barriers.Station a survey team at the barriers at the scheduled times, which should include all hours of system operation. Take a tally of people or vehicles passing through the system each minute. Figure 3 shows the "burst" effect resulting from people using public transit or carpooling. "Bursting" of this type strains access control systems.Note and photograph incidents affecting throughput, including access denials, equipment failures, breeches, deliveries, visitors and package inspections.

A good investmentAccess control traffic studies take time and cost money, but the improvements in security make them well worth the cost.

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© 2008 Penton Media Inc.

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