Guardrail Posts - Guillotines by the Side of the Road?
THE EFFECT OF CRASH BARRIER PROTECTORS!
by Edwin Hofbauer Vienna, Feb 23rd, 1995

THE CURRENT SITUATION

Since their introduction, metal guardrails have proven to be a very effective protection for motorists. But the safety experts did not consider the safety implications for motorcyclists resulting from them because motorcycling was decreaseding at this time. Since the eighties motorcycling has been booming again, and this has brought the problems into focus.

THE PROBLEM

The posts of crash barrier rails have edges sharp as a razor blade. Motorcyclists who fall off their bike in bends and slide towards the side of the road are almost unable to prevent an impact to these posts. This always results in serious or even fatal injuries. The acceptable limit for the biomechanical resistance of the human body is often exceeded. Parts of the body, e.g. the head, arm or leg can be cut off, the victims might bleed to death. Even low speeds of 20 mph often cause serious accidents which means that also moped riders and cyclists are at high risk.

In Germany every year approx 1000 to 2000 riders or passengers come into contact with crash barriers. Between 100 and 200 die from such impacts (1986). In Austria, out of the 273 killed riders in the last 3 years 41 (or 15%) died after a collision with crash barrier posts. Six out of 10 collisions with these posts caused serious injuries, one out of 10 were fatal. For the 10 million motorcylists all over Europe it can be assumed that an estimated 1.500 bikers or more annually are killed in this way, depending on the extent of the use of guardrails in the individual countries. The figures for moped and pushbike riders could not be quantified so far, but doubtless are high as well.

With a bicycle helmet, usually without a resistant outer shell, the victims are at great risk.

SOLUTION: CRASH BARRIER PROTECTORS (CBP)

To reduce the consequences of an impact to the crash barrier posts, their edges must be covered with CBPs made from impact absorbing materials. They consist of EPS (Expanded Poly Styrol), a foamed plastic, similar to the inner shell of a crash helmet, but three times as thick. This material mainly consists of air and only 2% of plastic. A cubic meter therefore weighs just 20 kilos. It is mainly used as packing material or for noise and temperature insulation. Other products consist of PE (Poly Ethylene, Neopolene)

The Austrian product developed by =D6AMTC is a one piece shell and open at the back, so it can be mounted radially to the post. They can be mounted within seconds, and compared to the accident compensation costs they are ridicoulosly cheap. Assumed, that posts are set every 3,5 metres, their coating in a 50 meter long curve costs only 700.- atS. The price is 50.- atS per piece. Although it is the cheapest of all offered products, this price can be remarkably reduced by a wide spread use all over Europe. Their long time durability against weather is at least 5 years. They can be recycled to the same product they were before. The protective effect of CBP covered guardrails for other motor vehicles remains the same. The ability of a protector to return to it's original shape is good enough for more than only one impact. Unobstrusive colour avoids the attraction of attention to the roadside.

The FEM-representative in your country is able to show you a sample. CBPs decrease both the impact force peak and the deceleration at a rate of 50% and double, if not triple the impact time compared to a bare IPE post. Coating posts with protectors covers the sharp edges and thus prevents fractures or the amputation of body extremties. CBPs SAVE HUNDREDS OF LIVES!

CROSS SECTIONS OF STANDARD CRASH BARRIER POSTS

I-posts or IPE 100/140 is made from red hot steel by roll milling like a rail.This form of cross section is mainly used in steel construction and therfore a cheap mass product.

Sigma-, Z- or hat- profile posts are made from sheet steel by an endless process off rolling and bending, which causes big outer radius of the cross section. Tests showed, that this can remarkably reduce (-25%) the consequences of an impact.

The aluminum post is the most used one in Austria. It is produced by trackpressing. It's edges are the most form aggressive ones of all posts and it is able to split helmet shells easily. Its the most dangerous one for two wheelers.

SCIENTIFIC INVESTIGATION

The "Institut Rechtsmedizin" at the University of Heidelberg (September 1984) used postmortal bodies as test objects. They were fixed to a sledge with stretched arms and both moved towards bare IPE posts, sigma posts and protector coated IPE posts. With bare steel posts, the arm was amputated at the sholder. Such injuries can be lethal, when the bleeding cannot be stopped early enough. The sigma-post showed better results. Although fractures occured, the arm was not amputated. However the injuries as these were classified as serious. The test with a CBP protected IPE post showed just contusions at all but no fractures.

Dipl. Ing. Peter Jessel from the Batelle Institut Frankfurt used Dummies "Sierra Hybrid II/Part 572" 175 cm tall, weight 75 kg). Also with stretched arms. he let them fall from a height of 4 metres both onto IPE 100-posts and coated posts. His conclusions also massively support the use of protectors.

Finally similar results at Schuberth Helmets in Braunschweig were found on a testing device for the ECE 22/02-approval of crash helmets.

The Effect of CRASH BARRIER PROTECTORS on Motorcycle Road Safety a scientific investigation by Dipl. Ing. Peter Jessel of the Batelle Institut Frankfurt
Impact Obstacle Imp speedMax Decel Max Force Imp Time
bare IPE 100-Steel post 32 km/h 2500 m/s2 18080 N 13 ms
IPE 100 POST; 32 km/h 1214 m/s2 9410 N 23 ms
covered with protector
difference [%] 		-51% m/s2-48% N+77%

RIDERS INITIATIVES

MAG Austria has started to distribute the protectors all over Austria, using the D6AMTC product, which is half the price of altenatives. Austrian riders have financed hundreds of them, and MAG could convince local authorities to follow. By 1995 more than 10.000 protectors will be mounted.

In 1984 german motorcyclists started mounting protectors with the approval by the Minister of Transport. Subsequently the governement has continued to do the work. So far about 1,5 million DM have been spent. The final goal is to convince the road safety authorities of the beneficial effect on safety and to convert it from a initiative of individuals into a part of the official road safety programme.

MOUNTING INSTRUCTIONS

CBPs have an unobstrusive appearance to avoid focussing one's attraction to the roadside. This should not be compensated i.e. by fixing brightly coloured advertising stickers on to it.

Of course CBPs have their biggest effect on twisty roads with a high motorcycle frequency.

ADDITIONAL SAFETY ALTERNATIVES FOR THE ROADSIDE

Double guided metal crash barriers prevent body contact to the posts (Fig 1).

Concrete or metal guard walls have an even surface with no posts at all and aditionally work as noise absorbers (i.e. against HGV tyre noise) (Fig 2).

Sigma-, Z- or hat profile posts have rounded edges and thus reduce the accident risk for two wheelers significantly. They should be used with any renovation, reconstruction and alterations of crash barriers.

Removing all crash barriers where irrelevant for road safety provides safety areas for two wheelers without obstacles.

Rounded or facetted kerbs instead of commonly used sharp edged ones are less form agressive and also reduce the consequences of a body or head impact. Luxembourg Motorcyclists Initiative (LMI) has experimented with cheap alternatives such as used tyres or sand filled plastic tubes.