Road work zone as a risk zone: Awareness must be sharpened
The M 6 near Manchester on the evening of 10 May 2005: Two men working at a motorway roadworks site as a women loses control over her vehicle. The car crashes through the traffic cone separating the work zone from the traffic lane, hitting the workers. Certain death for both workers, and the driver of the car also died in the crash. Karlsruhe motorway junction on 7 June 2005: On the A 8, a car travelling along the road work zone crashes into the barrier separating the opposite-way lanes, lifts off the ground and lands in the driver cabin of an oncoming HGV. This accident also ends with a terrible outcome: One dead and three badly injured, including one critically injured.
A total of 1,579 accidents happened at road work zones on Germany's motorways in 2003, with injuries recorded in 973 of these accidents. 25 people died, 191 were seriously injured and 1,298 suffered minor injuries. Speeding was the main reason for more than half of these accidents.
On Germany's motorways, road work zones are located on average every 30 kilometres and are an average 2.5 kilometres long. In 2004, road work was carried out for at least 14 days on 1,612 of the around 12,000 kilometres of motorway. This means that motorists are confronted with detours and narrower lanes, additional traffic signs and flashing lights, and often unclear and confusing road markings. All this demands enormous concentration from motorists. If the situation becomes critical, there is hardly any time to respond, and no room to avoid a collision.
When the police record an accident with injured victims at a road works zone, they are required to enter in the accident report not just the type of road, light conditions and road condition, but also as a special entry "work area". This data, however, is not analysed at a later point in time. This is why up to now it has not been possible to draw the conclusions from accidents at road work zones which would be so important when it comes to improving the design of road work zones.
There have been many studies carried out on the topic of accidents at road work zones – both on a national and international level. However, the conclusions differ dramatically: The percentage stated for accident risk in comparison to travel on open roads ranges from three to 450 depending on the section of the road work zone that was monitored, traffic routing and local conditions.
Dr. Wolfgang Schulte, former department head at Germany's Federal Highway Research Institute (BASt), in charge of work site protection and involved to a major extent in the drafting of guidelines for work sites (RSA) with performance requirements, also for the Federal motorways, remembers a study by BASt on how motorists behave at road work zones: Test drivers were sent through simulated road work zones and it was noted that they did not perceive the road work zone as a special event at all. The most frequent cause of accidents according to this study: Motorists wait too long to slow down in the so-called speed taper in advance of the road work zone, where the speed limit is gradually reduced, and are thus forced to brake too suddenly. In a trial, the lanes were narrowed in advance of the road work zone. The result was that motorists drove 20 kilometres per hour slower than previously.
Bumpers made of plastic are to bring greater safety starting in 2006, particularly for short-term road work zones. These bumpers are three centimetres high and two metres wide and are simply laid on the traffic lane. Positioned around 150 metres in advance of the road work zone, these bumpers serve as a "shake awake" call for inattentive motorists. These so-called warning bumpers are already in use in Spain and in the Netherlands.
From 1996 to 1998, the ARROWS (Advanced Research on Road Work Zone Safety Standards in Europe) international research project examined on behalf of the European Commission how motorists' behaviour can be improved in order to make driving through a road work zone safer. The national road administrations of Belgium, Germany, the Netherlands, Sweden, Slovenia and the Czech Republic were involved in this study which was managed by the National Technical University of Athens. One important finding of this study: Although motorists believe that they drive carefully through the road work zone and at the right speed, experimental studies and observations clearly show that this is, in fact, not the case.
The Institute for Transport Planning and Systems (IVT) at the Swiss Federal Institute of Technology Zurich (ETH) examined on behalf of Astra, the Swiss Federal Roads Authority, from January 2000 to June 2005, traffic behaviour and accident events on four of Switzerland's motorway road work areas because the accident rate on Switzerland's comparatively very safe motorways is around 50% higher at road work zones than on open roads. The precise analysis of these accidents shows that the accident rate varies strongly with different routing and also in the individual sections of the road work zone.
The accident black spot is the area between the lead-in/exit tapers at night, particularly with narrow lanes of two and a half to three metres in width, irrelevant of traffic routing. The same applies to points of entry/exit in the road work zone. Pile-up accidents, in particular, increase here. If only one lane is available in the area of the points of exit/entry (3+1), this accounts for more than half of all accidents. This is because vehicles slowing down, slowly exiting or entering have no room to avoid a collision. Omitting accidents in the points of entry/exit, the accident rate at road work zones on the whole would decline by 30 to 60 percent.
The Swiss study also noted that there was no correlation between the frequency of accidents and the traffic volume. On the six-lane motorway, three quarters of all accidents in the two most accident-critical sections occurred with medium traffic volumes. At peak times, the percentage of accidents declines. At times of low traffic, there are very few accidents.
In order to boost safety on Austria's motorway road work zones, the so-called road work zone management system was launched in 2001. This was a direct response to the deaths of 17 people in both 1999 and again in 2000 following serious accidents at road work zones, reports Robert Esberger from the Regional Development unit at Statistics Austria. The public Autobahnen- und Schnellstraßen-Finanzierungs-AG (ASFINAG) has set high standards: At all major motorway road work zones, opposite-way lanes must be separated by guiding walls made of concrete or steel. The taper zones are designed with additional guiding beacons and with running lights that are operated day and night, so that motorists are guaranteed the best-possible guidance. The speed of each vehicle is displayed on flashing, mobile speed displays and the speed limit is monitored by radar boxes. Improving traffic safety at road work zones costs ASFINAG an additional eleven million euro every year.
The positive outcome of these efforts one year later: The structural separation of opposite-way lanes alone reduced the accident rate by around one third. All in all, the number of accidents declined by 40 percent as did the number of people injured. The number of traffic deaths actually fell by 94 percent. And in 2003, no more deaths were reported.
An Italian study carried out from 1996 to 1999 on the A 18 between Messina and Catania on the island of Sicily points to difficulties when analysing accidents for road work zones "which make the entire procedure appear to be based on coincidence“ because the data material was often insufficient. On the one hand, the samples were not sufficiently representative and on the other hand fewer accidents were recorded than actually took place because the police are not called to each accident when nobody is injured. This is why petty accidents almost never appear in the statistics.
Important results of the Italian study: The length of the road work zone and the duration of the work have the greatest influence on the number of accidents. How long work is carried out is particularly important at the beginning of the road work zone: motorists who drive along this route frequently are familiar with the conditions and know how to behave in order to pass through the road work zone safely. On the other hand, traffic density and traffic routing with many curves are believed to be of no importance.
Conclusion: Although some studies on accidents at road work zones have been carried out throughout Europe, they merely provide isolated indications of the real reasons for accidents at road work zones. What is needed here is solid causal research and systematic data collection on a national and international level.
EuroTests - EuroTest 2005
Dr. Wolfgang Schulte, former department head at Germany's Federal Highway Research Institute (BASt), in charge of work site protection and involved to a major extent in the drafting of guidelines for work sites (RSA) with performance requirements, also for the Federal motorways, remembers a study by BASt on how motorists behave at road work zones: Test drivers were sent through simulated road work zones and it was noted that they did not perceive the road work zone as a special event at all. The most frequent cause of accidents according to this study: Motorists wait too long to slow down in the so-called speed taper in advance of the road work zone, where the speed limit is gradually reduced, and are thus forced to brake too suddenly. In a trial, the lanes were narrowed in advance of the road work zone. The result was that motorists drove 20 kilometres per hour slower than previously. 
The accident black spot is the area between the lead-in/exit tapers at night, particularly with narrow lanes of two and a half to three metres in width, irrelevant of traffic routing. The same applies to points of entry/exit in the road work zone. Pile-up accidents, in particular, increase here. If only one lane is available in the area of the points of exit/entry (3+1), this accounts for more than half of all accidents. This is because vehicles slowing down, slowly exiting or entering have no room to avoid a collision. Omitting accidents in the points of entry/exit, the accident rate at road work zones on the whole would decline by 30 to 60 percent.
Important results of the Italian study: The length of the