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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Centerline rumble strips on a two-lane, two-way rural road in Finland

Taristava keskiviiva valtatiella 5 valilla Leppavirta - Humalajoki

In this before-and-after study the effects of centerline rumble strips on traffic flow and driving behavior on a two-lane, two-way rural road in Finland were observed. The rumble strips were done by pressing strips on both sides of the centerline during asphalting work in August 2003. The before-study was done in July 2003. The first after-studies were done one month after the pressing of the rumble strips and they were repeated one year after the before-study. Every time field measurements were done on Thursday and Friday, but because of rain the one month after observations from Friday were not analyzed. The measurement methods were the license plate method, point measurements in an automatic traffic measurement point, video recording and lateral vehicle placement measurements using a laser distance measuring device. Furthermore, in the one year after situation roadside interviews were done in order to get drivers' opinion and experience of rumble strips. The road section with almost continuous centerline rumble strips was about 20 km long and the speed limit was 80 or 100 km/h. The ADT was about 6,000 veh/day. The flow rates in both directions of driving were mostly below 500 veh/h during all measurements. According to the results from the license plate studies the centerline rumble strips had no effect on the travel speeds in either direction. The mean travel speed in the northbound direction was 88.1 km/h in the before-situation, 87.9 km/h one month after, and 87.5 km/h one year after the implementation of rumble strips. In the opposite direction the corresponding figures were 87.6, 88.7, and 88.3 km/h. The observed differences in travel speeds are due to differences in the flow rates. Nor did the centerline rumble strips affect the standard deviations of travel speeds. The data from the point measurements showed that the rumble strips had no effect on mean spot speeds, standard deviation of speeds and platoon percentage. The results from the license plate studies showed that centerline rumble strips had no effect on the overtaking rates in either direction. The overtaking rate for light vehicles in the northbound direction was 0.57 active overtakings/km/h in the before situation, 0.55 overtakings/km/h in the situation one month after and 0.69 in the situation one year after. In the southbound direction the corresponding figures were 0.63, 0.57, and 0.52. The observed differences in the number of active overtakings were due to differences in flow rate. The results from the video recording of an about 700 m long straight stretch showed that driving on the centerline has decreased after the implementation of rumble strips. The share of vehicles waiting for overtaking opportunities on the centerline behind another vehicle decreased from 0.67% in the before situation to 0.15% in the situation one year after in the northbound direction. In the southbound direction the share decreased from 0.50% to 0.30%. The share of vehicles driving on the centerline without any obvious reason decreased to about half of the share in the before situation (north: 0.32% to 0.15%, south: 0.35% to 0.15%). For the later vehicle group the time spent on the centerline also shortened. The results from the lateral vehicle placement measurements showed that the centerline rumble strips had no permanent effect on the distance that drivers kept to the centerline. In the situation one month after the drivers in the southbound direction drove closer to and drivers in the northbound direction farther from the centerline than in the situation without rumble strips. However, in the situation one year after the distances, with the exception of one case, had returned to the same level as in the situation before. At one measurement point the drivers in the northbound direction remained driving 14 cm farther from the centerline than before. However, the traffic lane was 15 cm wider than before, and therefore it is possible that the change is a result from this and not from the rumble strips. In all other cases the change compared to the before situation was not over 1 cm. In the southbound direction the standard deviation of lateral vehicle placement was smaller in the situation one month after than in the before situation, and it still remained on the same level one year after. In the northbound direction the standard deviation first decreased, but in the situation one year after the standard deviation was on the same level as in the situation without rumble strips. This report may be found at http://alk.tiehallinto.fi/julkaisut/pdf/3200955-vtaristavakeskiviivt5.pdf

Language

  • Finnish

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Filing Info

  • Accession Number: 01014090
  • Record Type: Publication
  • Source Agency: TRL
  • ISBN: 951-803-559-8
  • Files: ITRD
  • Created Date: Dec 22 2005 1:56PM