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Flexible Bollards vs. Traffic Delineators

Which traffic safety equipment will provide best value for your application?

October 23, 2019

A black bollard with yellow reflective tape stands before a very blue sky
Flex-post bollards are useful on medians, in parking lots, and to mark bike lanes.

Bollards—the short posts that mark perimeters and guide traffic—are often made of steel or concrete, designed to stop a car in its tracks. Yet in some places, site planners don’t want a fixed bollard that could do vehicle damage or stop a car. Emergency vehicles may need to access a curb, even across a bike lane. Drivers often bump parking stops while trying to get fully into a space, and a hard bollard may cause unnecessary damage. In parking lots, having a lane marker may be necessary to separate traffic lanes—but frustrate wide-turning trucks. In these situations, a flexible solution is needed.

There have been two major approaches to designing flexible markers. In Europe, flexible bollards, based on regular traffic bollards, have become the norm. In North America, flexibility often comes from traffic-safety equipment, like channelizers and delineators. What is the difference between these approaches?

What is a delineator?

To delineate is to mark the position of a border or boundary: a “delineator” is something that indicates that boundary. In North America, the term almost always means a plastic post, wrapped with reflective tape, used to mark a traffic lane. These road markers are also sometimes called flexible channelizers. Portable delineators or channelizers are used to flag road work sites.

These traffic delineators are often used as permanent posts in parking lots. They guide drivers, but when hit, do not damage the vehicle. Later, they became popular as bike lane markers or as markers in a median. Beside bike lanes, these little posts have become critical infrastructure.

Orange and white flexible lane delineators mark a bike lane
Bike lane bollards prevent cars from using the bike lane for parking.

The importance of bike lane bollards

A painted lane on the side of the road is often not enough to encourage cycling. Population-wide studies show that physically-protected bike lanes are a big incentive to non-expert cyclists. Separated bike lanes encourage riders of all ages and abilities. Also, with only paint as a guide, bike lanes often become parking spaces.

Yet in some places, barriers and planters are a no-go, because emergency vehicles or garbage trucks need access to the sidewalk.

North American cities often use flexible traffic delineators as a bike lane separator. Made of inexpensive polyethylene, these slender posts do a very good job in low-traffic areas. Although they may be side-swiped, very few drivers will choose to drive over them to park their cars.

Polyethylene channelizers are sometimes overwhelmed in the harder conditions of a busy road. They can be destroyed if city vehicles run them over more than a few times.

Europe often installs larger, beefier polyurethane flexible bollards that have the look and feel of steel bollards. These tough flex posts are more expensive than the small polyethylene posts. They are also often hardier in high traffic conditions and narrow lanes. They can be driven over when necessary, especially by larger vehicles, but their solid dense profile deters cars from hitting them.

Traffic delineators as lane markers

Bright yellow traffic delineator on a 360° spring

Material:

Polyethylene post, various bases, often with a spring

Unit Cost:

$30-$60, depending on mounting options

Installation Cost:

Depends on installer and location. Epoxy less expensive than other methods.
Usually $60 to $150.

Diameter post:

2 to 3 inches

Diameter base:

6 to 8 inches

Height:

30 to 42 inches

Working Temperatures:

-10°C to 48°C (14°F to 118°F)

Impact Tolerance:

10-20 impacts

Thin polyethylene traffic delineators are often used to mark bike lanes. They are usually yellow, white, or orange, and have eye-catching reflective tape. Traffic delineators based on standard traffic-safety equipment are usually made of HDPE polyethylene. This material is familiar to most people as the type used for many plastic bottles. Thin polyethylene makes milk jugs; thicker versions make laundry detergent bottles and traffic safety equipment.

As a more obvious barrier than paint, these posts usually stop drivers from using the bike lane as a parking lane. A car parked on the wrong side of a barrier is obviously in the wrong space. Ticketing and towing are clear dangers.

These posts are also excellent for marking two-way traffic in bike-only lanes, especially near intersections. They guide cyclists to watch out for opposite-direction traffic. They can withstand being hit or brushed by cyclists many times.

However, these posts are less effective in preventing vehicles from entering cycling lanes. Vehicles turning through the bike lane often misjudge how closely their rear wheels will cut the corner. These little posts are often driven over as if they weren’t there. This causes a hazard. When the pole closest to the intersection goes down, drivers can start reading the end of the bike lane as a turn lane. They may begin to pull into the bike lane farther back than they otherwise would.

A benefit of these posts is that they are cheap and easy to install. However, in high traffic areas, they may need frequent replacement; sending a crew out and interrupting traffic costs time and money. Disappearing barriers can also create a traffic pattern change that may be dangerous to cyclists.

Tough flexible bollards

A black bolt-down polyurethane bollard with a reflective stripe on top

Material:

Polyurethane

Unit Cost:

$110-$330, depending on quantity
Removable lockable mount base extra

Installation Cost:

Depends on installer and location. $60 to $200 for regular mounts.
Removable mounts and embedded bollards need new-pour concrete: costs vary widely for installation.
Removable mounts can reduce replacement installation cost to zero.

Diameter post:

3-7/8 to 6 inches

Diameter base:

3 to 6-1/4 inches

Height:

31 1/2 to 40 inches

Working Temperatures:

-40°C to 60°C (-40°F to 140°F)

Impact Tolerance:

50 to 500 impacts

Polyurethane flexible bollards have a different profile and resilience. They feel a bit like the rubber of tires due to their density and having the same “SHORE D” hardness as tire tread. Since every point along the polyurethane bollard body is equally flexible, they have distributed rebound. This change in material and design makes these bollards hardier in regular traffic.

The rugged polyurethane can collapse entirely under a wheel, flat to the ground, at least fifty times. For smaller deformations, the bollards have been tested to withstand at least 500 impacts. With 25 times the resilience of a traditional polyethylene channelizer, any increased up-front cost can quickly become savings. A much lower replacement cycle also means less labor cost and traffic disruption.

The option of installing a removable mounting can also bring subsequent installation costs to zero. A new bollard can be easily swapped in during regular road maintenance.

Workers install flexible bollards in Salt Lake City Utah
Installed with removable mountings, these flexible bollards could be easily replaced.

A wider range of working temperatures also makes this bollard a good choice in wintery weather. Additionally, there is no metal spring to degrade in salty conditions or to jam with salt and road dirt.

However, the biggest difference with the European-style flexible bollard is in driver perception. Since the bollards look like their steel counterparts, vehicles avoid brushing against them. Additionally, their thicker profile grabs attention.

Eventually drivers come to know these bollards are flexible. Still, should a vehicle sideswipe such a bollard on a tight turn, the sound against the car body alerts the driver of impact. Next time, they’re more likely to note the bollard’s location. A polyethylene traffic delineator can’t replicate the sound.

The European-style is therefore more of a deterrent against getting hit. It invites less impact, while it endures more.

A line of black removable bollards creates variable access space
Flex-posts based on traditional bollards have a substantial, decorative look.

Many flexible options to choose from

As municipalities take aim at Vision Zero and active transportation targets, bollards are an inexpensive, versatile infrastructure option. They cut down on confusion and make expected behavior clear. In some spaces it’s important for emergency or city vehicles to be able to move where other vehicles cannot. When removable bollards aren’t a good traffic control solution, flexible bollards are very useful.

There are a wide range of options to select from, and all have their use. Questions around long-term value should include up-front costs, driver reaction, replacement cycles, and maintenance. In some places, inexpensive traffic channelizers are ideal. In other places, a more substantial flexible bollard may be the answer. Please reach out if you have questions about flexible bollards.

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