Vergleichende Betrachtung der Sicherheit und Wirtschaftlichkeit von Arbeitsstellen kürzerer Dauer auf Autobahnen bei Tag und Nacht

  • A comparative examination of the safety and cost effectiveness of short-term roadworks on motorways by day and by night

Kemper, Dirk; Steinauer, Bernhard (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2010)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2010


In Germany about 90% of the traffic volume in passenger transport and 65% in freight transport is borne by the motorways. The total amount of traffic on motorways has risen even more sharply in the last 20 years than the forecasts had predicted. Overall, roads are responsible for the most traffic by far and thus represent the backbone of the traffic infrastructure - this is particularly the case for motorways. Roadworks on motorways affect the efficiency of the section of road concerned through changes to traffic routing or lane closures. As a result disruption of traffic flow or congestion usually occur leading to an increase in road user costs. About 1/3 of lost time due to traffic jams on German motorways is a result of roadworks. A reduction of these costs would be possible by above all optimising the annually about 70.000 short-term roadworks (STR) which cause traffic jams. In particular shifting these roadworks from day to night is the most important alternative for significantly reducing road user costs. The safety aspects of night roadworks have however not yet been scientifically considered so concerns are repeatedly raised about this kind of roadworks. All the safety-related aspects of night roadworks were therefore considered with the aim of developing recommendations for carrying out short-term roadworks by night. This included analysing about 14,500 STRs and about 33,500 accidents on German motorways in the years 2002 to 2005 and evaluating them with regard to traffic safety and work safety. The examinations carried out showed that night roadworks do not have a higher hazard potential than comparable roadworks by day. The increase in the number of accidents in the vicinity of roadworks compared to the free road section is even smaller by night than by day. The number of accidents per 1000 STR hours is about 30% higher by day than by night, and the accident cost rates in the vicinity of STRs are also higher by day than by night. In general a main reason for the increase in the number of accidents in the vicinity of roadworks can be seen in the resulting traffic jams, first and foremost by day. Every traffic jam, especially the end of a tailback, represents a huge accident risk and should thus be avoided wherever possible. Based on the accident analyses, both organisational and technical measures could be developed and their effect on traffic and work safety be estimated. The organisational measures include recommendations for possible operating times and the conversion of personnel contracts to night work or shift work. The technical measures include additional elements of roadworks security, such as warning thresholds or overhead signals targeted towards preventing accidents within short-term roadworks. In addition proposals were developed for optimising warning clothing to ensure good visibility for construction workers especially at night. So practice-oriented implementation criteria for the right choice and application of economically and operationally tenable measures for reducing traffic jams were developed with a view to an increase in the operation of night roadworks in the future. Provision must be made in the planning of night roadworks for the recommendations suggested in the framework of this paper. Motorways are the main artery of the German economy and of mobility. For this reason traffic jam related interference of traffic must be avoided at all costs. As short-term roadworks are frequently necessary, there must be a transfer to night work in future in view of the increase in traffic. It is up to the transportation department to recognise the advantages of night roadworks and set the course accordingly.


  • Chair and Institute of Highway Engineering [313410]