Controlling vehicular and pedestrian traffic is a significant security concern, but the security risks can be dramatically reduced when using the correct perimeter and access solutions. 

With the advancement and convergence of security systems, gates, barriers and turnstiles are following in similar fashion. Innovative technologies are providing the best perimeter protection for high-risk sites while maintaining pleasing aesthetics. 

Barricade methods, in conjunction with an overall security system, will provide an effective means of controlling incoming and outgoing traffic. By combining several types of barriers, vehicles can be monitored and unauthorized access can be eliminated. 

Traffic of the pedestrian variety can be managed inside a facility as well with the use of turnstile and gate devices. Using the correct turnstile method — waist-high, full-length, optical, barrier-free or drop-arm — will regulate the directional flow of people and monitor incoming and outgoing patrons. Combining traditional turnstile and gate access devices with card readers and video surveillance systems will offer more efficient and secure access control. 

Securing the Perimeter and Controlling Vehicular Access
“Automated vehicular gate systems are the first line of defense at the perimeter,” says Richard Sedivy, director of marketing for Inglewood, Calif.-based DoorKing, a manufacturer of residential, commercial, industrial and maximum security gate and barrier operators.

While most barriers and bollards are capable of reducing the speed or demobilizing a vehicle in time for a security guard to react, not every barricade is suitable for every job. For most guard stations, a security barrier needs to be tailored to fit the specific security needs for that environment. 

“It basically comes down to control,” says David Dickinson, senior vice president of Palmdale, Calif.-based Delta Scientific. “If you have a guard roof and a car drives up, there is nothing a guard can do to stop the vehicle. There is nothing to physically stop him and there is no real control unless you have some kind of barricade.”

Determining the correct barricade is indicative to the threat and speed of a vehicle and the level of security needed for a specific area. The weight and velocity of a vehicle will determine whether or not the vehicle will breach the secured area. The payload stopping capability of a barrier or gate is key in choosing and implementing the correct device. 

Vehicle deterrence devices go through two types of testing to determine its payload-stopping capability. The first is a crash-rating test that is determined through computer analysis. The second method of testing is the actual crash test. Delta Scientific uses both tests to qualify its barricade products to ensure the correct stopping capability.

“The most effective means is to run a full crash test,” says Dickinson. “And secondary, we use computer modeling to study our designs and evaluate them.” 

The U.S. Department of State uses three barrier ratings based on a vehicle’s speed and the barrier’s stopping capability. A K4-rated barrier is able to stop a 15,000-pound vehicle traveling at 30 mph, while a K8-rated barrier will stop the vehicle at 40 mph and the K12 at 50 mph. A vehicle’s kinetic energy will determine its hitting power. Kinetic energy is determined through the velocity and weight of the vehicle. In addition, ratings of L1 through L3 are given to describe the distance a vehicle is expected to travel past the barrier after impact. 

Barricades are designed to absorb the vehicle’s kinetic energy upon impact; however, the faster a vehicle is traveling, the greater the likelihood of a breach. In order to prevent penetration into a secured area, entrances can be designed with sharp turns to force a vehicle to slow before reaching the barrier. This method significantly reduces the vehicle’s kinetic energy and its chances of breaking through the barrier.

Using Turnstiles to Direct Pedestrian Traffic
Turnstiles provide control and directional flow of pedestrian traffic inside any given structure. This form of gate permits access to only one individual at a time, allowing security professionals to monitor incoming and outgoing patrons.

“A turnstile gives true one-for-one access control; whereas a gate or a door, once activated and opened, can allow multiple entries. A turnstile will relock itself after each passage, ensuring only one person passes through for each activation,” says Jonathan Watson, director of international sales for Alvarado Manufacturing Co. Inc. of Chino, Calif. Watson, who has spent 10 years with Alvarado, has been involved in access control projects for many professional sports facilities and several college universities. 

“For most medium to high security applications for access control or time and attendance, facilities will opt to use turnstiles for general populace and have a gate to the side in order that ‘exceptions’ to the norm will have a means of entry,” Watson says. “But for lobby access and facility entry, the advent of optical turnstiles with acceptable passage widths — either barrier-free or with drop-arm or retractable wing barriers —have allowed companies to use a single device for everyone.”

Turnstiles are a successful method for controlling directional flow of pedestrians. One-way, exit-only or entry-only turnstiles are available for secure passages in or out of a facility. However, turnstiles are available in a variety of types, some of which are more appropriate for a given facility than another. 

For perimeter control, full-height turnstiles should be used to prevent patrons from jumping over the barriers. For lobby and access control, waist-high or optical turnstiles are more appropriate. Turnstiles also serve as a means to protect property and increase loss prevention; however, while restricting access into a building, emergency escape plans need to be well thought-out as well.

“Safety concerns must be considered with respect to facilities, and the ability to safely exit a building in an emergency is paramount. This is why all of our interior optical barrier turnstiles allow for emergency manual force opening,” says Watson. “All of our turnstiles allow for alarm inputs and can be set to automatically open in event of a power loss.” 

Guarding Against Pedestrian and Vehicular Tailgating
Tailgating has been a concern for both traffic control barriers and turnstiles. Once a vehicle has approached the guard shack, the risk of tailgating becomes a security concern. If permission is granted for an authorized vehicle to enter the restricted area, an unauthorized vehicle can also receive access by tailgating the vehicle into the premise. 

“There is another phenomenon with aggressive tailgating where the trailing vehicle will actually push the other vehicle through,” Dickinson says.

In order to prevent tailgating, inductive loop detectors (ILD) can be embedded within the barricade system. ILDs consist of one or more loops of wire embedded in the pavement and connected to a control box. When a vehicle passes over a loop, the presence of the vehicle is detected. ILDs can be used to detect the presence, passage, count and occupancy of a vehicle. 

“We can make stringent access control where only one car can get through a gate, or we can make it extremely stringent where you can’t get a car through,” says Dickinson. “We have the ability to moderate that.” 

Infrared detectors can also be used to prevent tailgating situations. These types of detectors are typically deployed in high security environments and are used in conjunction with sally port barricades. Sally ports consist of two sets of barricades with only one barricade being lowered at a time. This forces the vehicle to enter a small, secure space while the second barricade is lowered. This method makes it impossible for an unauthorized vehicle to tailgate and enter the premise behind an authorized vehicle. 

“Sally ports are used a lot in U.S. embassies,” says Dickinson. “Even if someone tailgates, they can’t get in.”

Turnstiles follow similar measures in preventing tailgating from occurring. Tailgating is addressed with the use of a physical barrier preventing an individual from entering through a turnstile without authorized access. 

“With optical turnstiles, tailgating is detected by infrared beams. In Alvarado’s turnstiles, a series of horizontal beams determines the presence of a person. If a second person is crossing the beams without first presenting access credentials, they will be detected as an attempting violation,” says Watson. “Optical turnstiles with barriers combine the best of both worlds in their ability to detect tailgating attempts and decrease the rate of unauthorized entries by physically resetting the barrier after each authorized passage.” 

Combining additional security system features with vehicular and pedestrian access control barriers will create an even more effective tailgating solution and guard against unwanted access. 

Integrating Overall Electronic Systems With Barrier Methods
Access control devices are more reliable when used with an overall security system; however, Dickinson explains that if a vehicular system is remote, there is always the risk of someone tampering with the wires and bringing the system down. For that reason, his company builds special barriers that “lock themselves up” in case someone tries to get in. 

Watson says turnstiles operate in a similar fashion and can be easily integrated with access control systems. 

“For very high security applications, the overall security system can be used to lock down turnstiles at any time. Many secure facilities that also have strong safety concerns will take advantage of the ability to treat the turnstiles’ directions independently. 

“A turnstile, furthermore, allows for much better information feedback to the facility’s overall security and monitoring system. Through passage feedback signals, which is standard for Alvarado equipment, it can be determined not only that someone swiped their card at a turnstile but that they also passed through it — accurate patron tracking and true anti-passback functions can be utilized because of this,” Watson says. 

Tracking patrons’ access is increasingly important in perimeter security as well. Incorporating an overall security system, including access control and video surveillance, will ensure more efficient security as vehicles can be viewed and recorded while passing through access points.

“Our systems are one component of the overall security system. We want the perimeter system to be strong all the way around. We don’t put a steel lid on a cardboard box,” says Dickinson. “If we have a barricade in the roadway, we don’t want someone going around it. There are some economic ways to accomplish that. You’re going to have camera systems and motion detectors and a human guard. If any one component is out, you’ll have less effective security.” 

Following Standards to Avoid Installation Hang-ups
As with any system, installation problems can be expected, but when manufacturers and installers take the extra step, additional troubles can be significantly reduced. 

After working with the Army Corps of Engineers for nearly four years, Delta Scientific was able to develop an access control standard for barriers. Dickinson says the standard is now being implemented at all Army bases in the United States and overseas. Creating a uniformed standard has prevented avoidable installation problems. 

“It is important before proceeding with plans to use turnstiles and gates where an industry professional can review the layouts and overall plans. Most security consultants, as well as others experienced in the field of turnstiles and gates, can see potential shortcomings, or overkill, with a given plan,” says Watson. “An expert consultant or product specialist can make sure the right products are being used for a particular application and that the layout and design achieves the intended function.” 

Sedivy agrees that the best tip on avoiding installation problems is to simply plan ahead. “Automated gate systems are fairly complex these days, especially when they are integrated with security systems, CCTV and barriers operators, something we term as ‘perimeter access management systems’ [PAMS],” he says. “Planning ahead can save a lot of headaches in the long run. Where is the power to be located, conduit runs, vehicle loop placements, access system components? [This] should all be known before the first concrete pad is ever laid.”

Watson suggests that once a layout has been decided, complete manuals and installation guides should be requested from the manufacturer. “The manuals will not only tell the user and installer about what will be needed for installation and maintenance, but will also give detailed information regarding site planning including conduit requirements, electrical needs and concrete pad specifications.” 

DoorKing has worked on many projects, including high security areas on Army and Air Force bases, airports and seaports, power plants and water treatment plants, and has found the best way to ensure a smooth installation is to adjust to the needs of that project. 

“In many of the high security-type projects, you have to adapt your product to work in a specific way for the application it is in,” Sedivy says. 

While working on a project at Stanford University in Palo Alto, Calif., DoorKing did just that. “[The university was using] our telephone entry systems for student housing and wanted to interface our programming software with the university’s main frame computer. Our software engineers got together with their software engineers and made it happen,” Sedivy says.

Adjusting to the project requirements will not only make the customer happy, but will also warrant a smoother installation. 


Controlling Vehicular Traffic With the Correct Barricade 

A secure perimeter is essential in sensitive areas. Barrier methods and barricades can be used to restrict access as well as control access. Choosing the correct barrier depends on the traffic flow, performance needs, and the size and speed of approaching vehicles. Barrier options include: 

Bollard — A bollard is a post made of concrete, stainless steel, aluminum, cast iron or other durable material that creates an aboveground obstacle and can be fixed or retractable. Bollards are constructed to completely stop most vehicles. 

Cable barrier — Cable is fastened to each post and is periodically anchored. The barrier prevents light vehicles from crashing through a standard chain-link fence.

Chain-link gate reinforcement — Wire ropes are fastened to gates and anchored on either side of the gate. For a relatively weak gate, the reinforcement transfers the force of a vehicle impact to a more substantial anchor system.

Concrete barrier (jersey barrier) — These barriers can be used around a fixed site as a perimeter vehicle barrier. Barriers can also be arranged to direct and slow traffic flow into a site. Dragnet — This consists of a chain-link “net” assembly with arresting cables attached to an energy absorber that is attached to the anchor system. The dragnet is suspended above the access road and dropped on a vehicle to absorb energy and bring the vehicle to a controlled stop. 

Electronic Barrier Gate — Chain-link gates and turnstiles used for vehicle and personnel entrances, electronic barrier gates may be activated by remote switch, numerical code or card reader.

Hydraulic Barricade — Upon major impact, the lifting mechanism absorbs the shock. In emergency situations, a steel barricade closes off vehicle access in just 1 second.

Source: Federal Transit Administration