Influence of Roadside Environment and Road Structures on Blowing-Snow-Induced Visibility Hindrance on Winter Roads : Analysis using the results of weather observations by a visibility observation vehicle during blowing snow. Hokkaido Sapporo 2016 International Conference & Workshop on Winter Maintenance and Surface Transportation Weather Tokyo Civil Engineering Research Institute for Cold Region Hirotaka Takechi, Masaru Matsuzawa, Yasuhiko Ito and Tetsuya Kokubu
Outcomes To clarify the influence of following items on blowing-snow-induced visibility hindrance Road structures Length of windward flat land Width of roadside tree belt Width of roadside rows of houses Presence/absence of guardrails
Outline Background and objectives Method of moving weather observation Method of multivariate analysis Results of analysis Conclusions
Background Winter Road Problems in Hokkaido Hokkaido Tokyo Traffic hazards Poor visibility and snowdrift caused by snowstorms
Background Installation of blowing-snow control facilities to mitigate traffic hazards caused by snowstorms Snow fences Snowbreak Woods It is important to accurately determine which locations are at risk of blowing snow.
Objective It is necessary to develop the technology for risk assessment of snowstorms along entire routes for appropriate installation. Present technology for risk assessment of snowstorms The Highway Snowstorm Countermeasure Manual The Degree of Snowstorm Danger Risk assessment of snowstorms http://www2.ceri.go.jp/fubuki_manual/index_e.html (Image) http://www2.ceri.go.jp/fubuki_manual/pdf/manual.eng.pdf
Snowdrift factor Objective Windward flat land Volume of On The Highway Snowstorm snow settled at snowdrifts Countermeasure Manual Snowfall(snow depth) The degree of Snowstorm Danger Items and scores used to Roadside trees and houses Poor visibility factor assess the degree of Road structure snowstorm danger were determined empirically Frequent occurrence of blowing snow Snowfall(snow depth) To clarify the influence of the road environment and structures on blowing-snow- Roadside trees and houses induced visibility hindrance To survey by moving weather ランク 総合評点 判定 observation on winter road Degree of 44 点以上 吹雪による障害の危険性が極めて高い A snowstorm 吹雪による障害の危険性がある B 21-43 during blowing snow 吹雪による障害に対して注意を要する danger C 1-20 0 以下 吹雪対策の必要なし D
Method of observation Moving weather observations were conducted during blowing snow by a visibility observation vehicles. Visibility, Wind velocity, Wind direction, Air temperature, Latitude and Longitude data ( Sampling interval was 0.1 sec . ) Sonic wind sensor (CLIMATEC,Inc CYG-85004) Installation height of 2.8m Forward scattering visibility meter (Meisei. TZF-31A) Installation height of 1.75m Visibility observation vehicle
Method of observation Locations of observation R238 Hamatonbetus city, Sarufutsu city R238 Saroma city, Monbetsu city R232 Enbetsu city, Haboro city R231 Iishikari city
Method of observation Observation period : Three winters periods of 2012 to 2013, 2013 to 2014, 2014 to 2015 Date of observations Number of observations KP Route Date of observations Number of total ※ Maximum section observation times 2012/12/26 10:49 - 16:23 14.7 - 41.4 9 2013/3/10 15:15 - 18:11 14.2 - 51.7 4 2014/1/13 12:48 - 16:04 14.3 - 51.7 3 Route231 2014/1/28 18:26 - 22:15 15.0 - 52.0 5 in Ishikari city 43 2014/1/31 14:44 - 17:44 15.0 - 52.0 4 (KP14.2-52.0) 2014/3/6 14:51 - 17:48 17.0 - 26.0 3 2015/2/2 15:13 - 20:05 15.0 - 42.0 8 2015/2/15 10:22 - 18:19 15.0 - 42.0 7 2012/12/27 8:52 - 16:05 35.9 - 76.5 6 2013/2/2 19:49 - 20:26 52.8 - 73.0 1 2013/2/3 8:32 - 9:32 51.8 - 68.5 2 2013/2/5 14:58 - 15:34 44.3 - 70.4 1 2013/2/20 6:32 - 12:51 41.6 - 71.2 7 Route 232 2014/1/11 11:25 - 15:22 36.0 - 71.4 4 from Enbetsu to 2014/1/28 16:00 - 21:01 35.9 - 71.4 4 48 Haboro city 2014/1/29 8:50 - 14:11 35.3 - 57.5 5 (KP35.3-81.0) 2014/1/31 17:33 - 18:52 36.0 - 71.4 2 2014/2/3 9:54 - 12:43 36.0 - 64.4 4 2014/3/7 15:44 - 16:43 47.0 - 64.0 2 2015/1/7 15:40 - 21:58 42.0 - 75.0 7 2015/1/8 11:35 - 11:50 71.0 - 81.0 1 2015/3/11 17:20 - 19:58 38.0 - 70.0 2
Method of observation Observation period : Three winters periods of 2012 to 2013, 2013 to 2014, 2014 to 2015 Date of observations Number of observations KP Route Date of observations Number of total ※ Maximum section observation times Route 238 2013/2/8 9:54 - 16:51 63.7 - 102.3 6 from Saroma to 2013/3/2 15:05 - 17:23 52.1 - 77.3 1 10 Mombetsu city 2014/2/9 17:41 - 23:27 54.6 - 90.2 2 (KP52.1-102.3) 2014/2/17 8:07 - 10:55 74.0 - 102.0 1 2013/1/26 11:40 - 16:11 229.2 - 235.6 8 2013/2/3 12:40 - 15:52 217.9 - 274.3 3 Route 238 2013/12/27 18:17 - 22:20 217.1 - 258.5 2 from 2014/1/26 16:10 - 16:41 236.9 - 258.5 1 Hamatonbetsu to 36 2014/2/5 5:31 - 5:49 240.0 - 251.9 1 Sarufutsu city 2014/2/10 14:44 - 18:38 219.6 - 257.4 4 (KP216.0-274.3) 2014/2/18 7:50 - 14:18 216.0 - 262.0 6 2015/2/27 8:27 - 20:05 225.0 - 257.0 9 2015/4/15 21:53 - 0:26 222.0 - 258.0 2
Method of analysis Multivariate analysis Mathematical quantification theory class I ( Hayashi's quantification method I ) Data were gathered for each 50-m section of road. Average of observed visibility values Data on road structure, roadside environmental conditions from road inventories, maps, and aerial photographs
Method of analysis 1. Response variable Visibility hindrance occurrence rate (%) Number of occurrences of avg visibility < 200m × 100% Number of total observation times
Method of analysis Independent variable 2. Independent variable Item Category 0 Cut of higher than 5.0m 1 Cut of 0-5.0m Road structure Road structure 2 Fill of 0-1.0m (Height of cut and fill ) 3 Fill of 1.0-3.0m 4 Fill of 3.0-5.0m Length of windward flat land 5 Fill of higher than 5.0m 0 N/A Width of roadside tree belt Length of 1 10-100m flat land windward 2 100-300m Width of roadside rows of 3 More than 300m 0 N/A 1 Scarce houses 2 10 ～ 30m 3 30 ～ 50m Width of tree belt Presence/absence of 4 50 ～ 100m 5 100 ～ 200m 6 200 ～ 300m guardrails Windward 7 More than 300m 0 N/A 1 Scarce 2 10 ～ 30m A road section without Width of rows of 3 30 ～ 50m houses 4 50 ～ 100m blowing-snow control facilities 5 100 ～ 200m 6 200 ～ 300m 7 More than 300m were studied. Presence/absence 0 Absent guardrails 1 Present
Results of analysis Partial Independent variable Item Category Response variable p-value correlation ( Item and category ) range score coefficient Road structure 0 ： Cut of higher than 5.0m -0. 0.101 101 1. 1.950 950 0.104 6.5×10^-7 Visibility hindrance (Height of cut and fill ) 1 ： Cut of 0-5.0m 0. 0.393 393 occurrence rate (%) 2 ： Fill of 0-1.0m -0. 0.462 462 3 ： Fill of 1.0-3.0m -0. 0.197 197 4 ： Fill of 3.0-5.0m 1. 1.488 488 ※ The rate (%)= Number of occurrences 5 ： Fill of higher than 5.0m 0. 0.723 723 of avg visibilty < 200m Length of 0 ： N/A -0. 0.547 547 1.681 1. 681 0.114 4.5×10^-8 × 100% Number of windward flat land 1 ： 10-100m 0.087 0. 087 total observation times 2 ： 100-300m 1. 1.305 305 3 ： More than 300m 1. 1.134 134 Width of windward 0 ： N/A 0. 0.120 120 1. 1.591 591 0.056 7.6×10^-3 tree belt 1 ： Scarce -0. 0.245 245 2 ： 10 ～ 30m -0. 0.166 166 3 ： 30 ～ 50m -0. 0.052 052 4 ： 50 ～ 100m -0. 0.386 386 5 ： 100 ～ 200m -0. 0.790 790 6 ： 200 ～ 300m -1. 1.189 189 7 ： More than 300m -1. 1.471 471 Width of windward 0 ： N/A -0. 0.294 294 6. 6.090 090 0.156 4.8×10^-14 rows of houses 1 ： Scarce 0.933 0. 933 2 ： 10 ～ 30m 1.776 1. 776 3 ： 30 ～ 50m 4.412 4. 412 4 ： 50 ～ 100m 1.760 1. 760 5 ： 100 ～ 200m 0.206 0. 206 6 ： 200 ～ 300m -0. 0.363 363 7 ： More than 300m -1. 1.677 677 Presence/absence of 0 ： Absent -0. 0.375 375 1. 1.532 532 0.118 1.3×10^-8 guardrails 1 ： Present 1. 1.157 157 2.761 2. 761 Constant
Category score of each item Categor egory S y Score -2 -1 0 1 2 3 4 5 Cut of higher than 5.0m (Height of cut and fill ) Cut of 0-5.0m Road structure Fill of 0-1.0m Fill of 1.0-3.0m Fill of 3.0-5.0m Fill of higher than 5.0m Results of analysis N/A windward flat Length of 10-100m land 100-300m Category for each item More than 300m N/A Width of windward tree belt Scarce 10 ～ 30m 30 ～ 50m 50 ～ 100m 100 ～ 200m 200 ～ 300m More than 300m N/A Width of windward rows of Scarce 10 ～ 30m 30 ～ 50m houses 50 ～ 100m 100 ～ 200m 200 ～ 300m More than 300m Absent Guardrails G Present Constant C
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