In connection with road maintenance in winter conditions when two plow trucks plows each lane diagonally in front of each other, have rear-end accidents occured. The work with tandemploga perceived as risky because of plow cars poor visibility, the low speed, accessibility deterioration of road and visibility is poor because of snow weather conditions and sometimes darkness.
To increase the security a research project is implemented in which a new type of illuminated signs are tested. Signs are mounted at the rear of the plow trucks and shows through a flashing cross when it is not appropriate to pass, and with flashing yellow arrow when it is possible to pass and also on which side overtaking can take place. The test runs during the winter 2010/2011 on two sections along the E4, Hudiksvall-Gnarp and Jönköping-Gränna. LTU will evaluate the behavior of the road users when the sign are used.
The project was funded by the Swedish Transport Administration