Narrow cross sections without centre line markings – “2 minus 1” rural road

af Lene Herrstedt

Summary Note

          Speed limits are still exceeded and mean speeds are still too high compared to the signed speed limits.

On road sections with signed speed limit 50 km/h the mean speed is          60 km/h to 65 km/h and 85%-fractiles are 69 km/h to 76 km/h after implementation of the new profile. On road sections with signed speed limit 40 km/h the mean speed is 53 km/h to 57 km/h and 85%-fractiles are 63 km/h to 68 km/h after the implementation. On road sections with signed speed limit 60 km/h the mean speed is 69 km/h to 70 km/h and 85%-fractiles are 78 km/h to 81 km/h after implementation of the new profile.

It is concluded that the concept has not been as effective as intended 

          The drivers seem to behave as intended in meeting situations on road sections. Drivers give way to the on-coming drivers by changing the lateral position to the right and in some cases the right wheels are crossing the intermittent edge line a little bit as intended. On-coming traffic pass in both directions without problems even though the “2 minus 1” road has only one central driving lane (see figure 5)   

          Mostly the meeting situations at speed reducers are handled without problems. The drivers seem to interact and adapt speed when approaching a narrowing letting the first arrival pass first. Problems are observed though in 5-10 % of the observed situations. It is not always quite clear to the drivers who should be the first to pass the narrowing. (see figure 4). In some cases both drivers stop and wait for each other to pass. In other cases one of the drivers continue without slowing down “forcing” the on-coming driver to give way. Accidents are observed in the narrowed speed reducers because of this confusion among drivers. A simple solution to this minor problem could be a sign telling the drivers who should go first.

          No conflicts have been observed in the transition zones where road profile changes from “2-1” to the ordinary two-lane cross profile. Drivers seem to follow the road markings as intended.

          At intersections drivers still stop at the stop line as intended. The apprehension for drivers not to stop before reaching the intermittent edge line on the crossing road seems to be unfounded.

          Repeated AFTER registrations on speed (July 2005) and “meeting behaviour” (June 2006) confirm the conclusions described above.


The evaluation results summarised above are expected to be supplemented by an accident analysis after the end of 2007. 

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