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Citation |
Nyberg J, Laine M, Rajamäki R. Res. Rep. Finn. Transp. Agency 2011; (60): online. |
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Copyright |
(Copyright © 2011, Finnish Transport Agency) |
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DOI |
unavailable |
PMID |
unavailable |
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Abstract |
Wide central markings were implemented on an 11 km long road section of main road 8 at Laitila and on a 4 km long road section of main road 9 at Tampere in the summer of 2011. The width of the central area was 0.7 m. The width of the lane was reduced by 0.25 m with the new markings. A no overtaking zone was also marked on the test road section of main road 9. The average speed was measured at one location at both test road sections. On main road 8, following the implementation of the wide central area, average speed was reduced by 0.7 km/h towards Rauma and increased by 0.6 km/h towards Turku. On main road 9 the average speed was reduced by 0.5 km/h towards Jyväskylä and stayed the same towards Tampere when the variable speed limit was 100 km/h. When the variable speed limit was at 80 km/h average speed was increased by 1 km/h. The speeds of passenger cars and vans were reduced more than the speeds of trucks and buses. The average speed was reduced with 1.0-3.4 km/h in every measuring point when it was dark. Cruising speed was reduced by 0.7 km/h on main road 8 and by 1.9 km/h on main road 9. The number of overtaking manoeuvres stayed the same. The vehicles' distance from the central line changed only at one measuring point. At the other points the distance stayed the same. In these three points the vehicles driving towards the opposite directions were already further away from each other than normally expected, prior to the implementation of the wide central area. Turning manoeuvres to the left were examined at a busy private road crossing. The wide central area markings seem to make overtaking the turning vehicle more difficult to a certain extent, particularly when the turning or overtaking vehicle is large. Drivers were interviewed in service stations near the test road sections. The number of interviewees was 128. Opinions about the wide central area markings were mainly positive. 74 % of the drivers interviewed considered the markings useful for traffic safety. 65 % of the interviewees also believed that the wide central area markings should be implemented more often. The criticism received was mainly about the decreased comfort in driving, probably because of the narrowed lanes. 50 % of the motorcyclists criticized skidding and vibration effects. The results of the study were compared to a study made in 2009 in which the wide central area was one meter wide. When the central area and the lanes were wider, the distance between vehicles driving in opposite directions increased significantly but the changes in driving speeds were insignificant. In this study, with narrower central area and lanes, the distance between vehicles driving in opposite directions did not increase in every measuring point, the cruising speed decreased and the changes in the spot speeds varied. Both increase in the distance between different travel directions and reduction of speeds is striven with wide central area markings. Therefore it is recommended that wide central area markings should be at least one meter wide in the future so that the distance between different travel directions would increase. This marking is estimated to reduce head-on collisions and drifts to the left with 10 %, and if the road section does not have centerline rumble strips, with 19 % altogether. |