Physical access control is the selective restriction of access to space.
The simplest and most common example is a locking door. You can walk through unimpeded while it is open, but you can’t pass once its locked. Fob controlled gates, RFID doors, and password-restricted IT systems all operate on the same general principle.
This post compares physical controls for spaces that routinely switch between pedestrian and vehicle access.
Public parks, walkways, and plazas are pedestrian only spaces, but there is a long list of special vehicles that require access – ambulances, fire trucks, police, maintenance vehicles, construction crews, and any number of other necessary services.
The reverse is true for roads and parking lots. They are normally vehicle-dominated spaces, but sometimes they are adapted for pedestrian use. Some roads are open to vehicle traffic during the week, but become pedestrian only for weekends and special events.
In either case, the access control measure needs to adapt to changing access requirements over time.
Comparing access control measures
Adaptable access control measures provide a smooth transition between restriction and access.
Of course, ease of transition needs to be balanced with security. Sturdier, more secure measures usually require more work to move.
The best access controls are both secure and adaptable. They are expensive to install, but a worthwhile investment for spaces that demand regular access changes.
How frequently do the access requirements change? Only in emergencies? Several times per day? The answers to those questions inform the choice of access control for a given locale.
Adaptability rating: Very low
Concrete barriers are the least adaptable access control in regular use. Their weight makes them ideal for protecting construction workers in high-traffic areas, but it also makes them impractical for anything other than long term work sites. In fact, concrete barriers are so difficult to move that they barely fit the definition of access control at all – they are often used in permanent highway barrier installations
Water-filled plastic barriers
Adaptability rating: Low
Water-filled plastic barriers are frequently used to transform roadways into pedestrian spaces or temporary work zones. They are more portable than concrete barriers, only taking on their full weight after being filled with water. Due to the intensive effort required for their set up and take down, plastic barriers are usually reserved for one-off events where a long-term solution isn’t practical, and then only when security trumps adaptability.
Adaptability rating: Medium
Removable bollards are an economical solution for areas that require long term access control. Bollard posts allow pedestrians and cyclists through unimpeded, but act as an effective barrier to vehicle traffic. Their simplicity and effectiveness make bollards a popular choice for park entrances and building plazas.
When a vehicle requires access, anyone with the correct key can unlock the post from its concrete-embedded anchor. Moving a bollard is many times easier than taking down a barrier, but it’s still not exactly convenient. The mover needs to unlock the post, pick it up, and walk it to the designated storage area When it’s time to leave, the process is repeated in reverse.
Removable bollards are perfect for areas that need occasional vehicle access, but they might get difficult to manage in high-traffic areas.
Adaptability rating: High
Retractable bollards are similar to removable bollards, with the added benefit of being self-storing. Instead of detaching from an embedded anchor, retractable bollards lower into a ground receiver – there is no need to move or store a heavy post.
The reduction in heavy lifting and transport make retractable bollards an appealing option in areas that require routine transitions between vehicle restriction and access.
Most bollard receivers sit flush with the surface to eliminate any tripping hazard while they are in the “down” position.
Adaptability rating: High
Collapsible bollards fold down for rapid vehicle access. They can be locked in the upright position, or left unsecured for rapid emergency response.
Because the bollard lies across the ground in the down position, some vehicles may not have the necessary clearance to pass over them.
Collapsible bollards are best for short term vehicle access for emergencies and deliveries. They aren’t recommended for busy pedestrian areas, as the collapsed post poses a tripping hazard.
Automated Retractable bollards
Adaptability rating: Very high
Automated retractable bollards can be directed to raise and lower by a remote computer system. They are extremely secure, and almost invisible when in the down position.
The initial installation cost for automated bollards is high, but the cost is worth it for high traffic areas with very frequent changes in access. A transition that may have taken several minutes with a removable bollard can be accomplished in seconds with an automated model – a necessity for both emergency and routine adjustments.
- Blue concrete barriers: Richard Smith, CC BY 2.0, via Flickr
- Plastic barriers: thisisbossi, CC BY 2.0, via Flickr