Motorway construction sites are often associated with a number of accidents above average value. An investigation of the road traffic safety of motorway construction sites forms the basis of this final report. The higher accident frequency in these sections as it is described in former investigations is confirmed in this report. However, the accident severity is less serious than on motorways without construction sites. In motorway construction sites the ratio of accidents with personal injury is with 6% around half under the value of sections of the motorway without construction sites (12%). Most of the accidents occur in longitudinal traffic (68%) often by lateral stripe of vehicles travelling in the same direction. An investigation of especially narrow motorway construction sites showed that these cannot be reckoned as unsafe in general. Rather there results a negative influence on traffic safety from different factors in connection with the low width. Bad or missing marks especially on the right roadway edge as well as short, even if only optical, constriction of the roadway or lane widths count to it. The lower driven speeds within the construction sites have an essential contribution in the lower accident severity. However, the permissible speed limits from 80 km/h or 60 km/h will usually be exceeded around 5 km/h to 10 m/h. In front of the first lane crossover point in the beginning of the construction site a speeding up to 40 km/h (V85) above the allowed maximum speed were observed. Compared with the stretches within, but also compared with the approach sections before the construction sites all sections of special traffic routing within the construction sites like lane deviations or crossover points show a lower traffic safety. The study of measures to improve road safety in these sections shows that emphasizing traffic signs by selective-yellow “Typ-3-Reflexfolie” can increase the attention for the special situation. In the section with the highest speeding in front of the first crossover point of the construction site a reduction of the driven speeds about 7 km/h was also achieved as well as a reduction of the left driver‘s proportion. Covered to the accidents often appearing here in the longitudinal traffic by lateral stripe of vehicles going in the same direction a positive effect on the road safety can be derived from the results. In addition to the emphasizing traffic signs a gradual increase of the speed limit after the construction site also led to better conformist speed behaviour, expressed by V85. Before as well as after the construction sites a lower range of driven speeds was reached thus. Especially on motorways this is an important criterion of the traffic safety. (Author/publisher)
Abstract