Drivers’ decision-making supported by The Snow Visibility Information system Kokubu, T., Takechi, H., Harada, Y., Omiya, S., and Matsuzawa, M Civil Engineering Research Institute for Cold Region (CERI), PWRI, Japan Introduction
Hokkaido is the northernmost island of Japan.
Hokkaido Sapporo, CERI
Max:208cm=6ft9in Jan 30, 2012 Iwamizawa 30km (19miles), NE. of Sapporo
[ 2 ] Background Flood Bank collapsed 1% Eruption Risk of road flooded 1% High wave Snowfall Road flooded Snowstorms cause ...
National road closure Risk of landslide in Hokkaido Snowstorm 1998 - 2007 Total ; 2020 times Poor visibility Winter Landslide Avalanche Summer Risk of avalanche 5%
Causes of national road closure in Hokkaido Snowdrifts
* 40% of road closures - snowstorms [ 3 ] Background Reduce damage caused by snowstorms ... Snow break woods Road: Installation of blowing-snow control measures Driver: Help drivers to make safer decisions
Snowstorm visibility information
Information Snowstorm Blowing-snow control facilities
Chose safer route
Visibility Information Snow fences * Control measures are installed in areas storms frequently occur. * Recently, bomb cyclones cause blowing-snow. * Snow-control facilities require much time and cost to construct, [ 4 ] so cannot address sudden storms. Objectives “Northern Road Navi” Website” - Portal Site for Road in Hokkaido - Hokkaido Road Information
Contents Website • What’s New • Distance & Time • Mountain Pass / Live Camera • Road Map • Links to Weather Info + Snowstorm visibility infomation URL: http://northern-road.jp/navi/ [ 5 ] Method of estimating visibility during snowstorms
Relationship between visibility during snowstorms and the mass flux of snow
……… (1) (Takechi, 2009)
Vis [m] : Visibility
Mf [g/m2/s] : Mass flux of snow
The mass flux of snow is the mass of snow particles snow particles passing through a specific unit cross-section during a particular unit time
[ 6 ] Method of estimating visibility during snowstorms Relationship between the mass flux of snow and the snow concentration
…………(2)
Mf [g/m2/s] : Mass flux of snow 3 N [g/m ] : Snow concentration The snow concentration is the mass of snow particles in a particular unit space V [m/s] : Wind velocity
Wind velocity
Mass Flux of snow Snow Concentration [ 7 ] Method of estimating visibility during snowstorms Method of estimating the snow concentration Estimation using snowfall intensity, wind velocity and air temperature …………(3) (Matsuzawa et al,1998)
Snowfall Drifting snow P [g/(m2s)] : Snowfall intensity wf [m/s] : Falling velocity of snowfall particles ( = 1.2 [m/s]) wb [m/s] : Falling velocity of suspended snow particles ( = 0.35 [m/s]) z [m] : Height of the viewpoint of small-vehicle drivers ( = 1.2 [m]) zt [m] : Reference height (0.15 [m])
Nt [g] : When snowfall intensity is high. Nt = 0.166・e0.309・V10
When snowfall intensity is low or zero Nt = 0.274・e0.401・V10 (Where, V10 is the wind velocity at a height of 10 m) U* : Friction velocity ( = 0.036×V10) K : Karman’s constant ( = 0.4) [ 8 ] Method of estimating visibility during snowstorms Judgment of visibility conditions
In providing the information, to facilitate understanding of visibility during snowstorms, the estimated visibility was classified into five levels ranging from 1,000 m or more to less than 100 m.
[ 9 ] Snowstorm Visibility Information System
Snowstorm Visibility Snowstorm Visibility Information for PCs Information for smart phone
24 hour later
As of March 10 2015,15:00(It’s renew 30minitues) Wakkanai Forecast
Abashiri Rumoi GoodGood ((1,000m1,000m oror more) Asahikawa Otaru Somewhat poor (500-999m)
Sapporo Poor Kushiro (200m-499m) Quite poor Muroran (100-199m) Significantly poor (less than 100m) Hakodate Area: [ 10 ] 221 areas in Hokkaido E-mail delivery service Conditions for Automatic E-mail Delivery Receive e-mails informing of poor visibility forecasts Reduction of visibility in the Nemuro north area 200 m is expected over the next 6 hours due to snowstrom. Please monition conditions and consider you safely when driving during his period. 2015/01/09 06:01:12 [email protected] ( ) [email protected] Nemuro north area 6 o’clock：Reduction in visibility range Nakashibetsu town 1hour delay ：
Reduction of visibility in the nemuro north area □ less than visibility 500m less than 100m 200 m is expected over the next 6 hours due to □ snowstrom. Shibecha townless 1hour than 200 delaym ： Please monition conditions and consider you safely when driving during his period □less than 100m INemuro north area visibility less than 100m Nakashibetsu town 1hour delya ： visibility less than 100m Shibecha town 1hour delya ： ： visibility less than 100m ： ： ↓↓for details↓↓ ↓↓for details↓↓ PC web site For PC website http://northern-road.jp/navi/touge/fubuki.htm http://northern-road.jp/navi/touge/fubuki.htm□3hours □ 6hours ：
[ 11 ] The number of visitors to the Snowstorm Visibility Information Website ( this winter )
Cumulative page views (PC and smartphone) MAX：30,547views 30,000 The Japan Meteorological Agency announced that the snowstorm would
Page views per Page views per be on a scale of that occurring only once in several years.
20,000 Mean for Nov. 28 through Mar. 31 4,154 views per day
day 10,000
0 December January February March November [ 12 ] Users questionnaire.
Implemental method: questionnaire is the home page.
Period of the execution: 2015. 4.21 ～ 5.20
The number of respondents: number of 483
[ 13 ] Users questionnaire. Aim of a questionnaire survey: Of the user, to grasp the Utilization of snowstorm
visibility information.
And, we want to clarify the validity. We wants to clear the future problem.
- Website service - satisfaction - change is doing plane - E-mail service - satisfaction - behavir change planning answers
[ 14 ] The attribute of the questionnaire respondent
The age composition The main use purpose More than 70 20 Year Old years old , 3% Generation, 3% Other, 4%
60 Year Old 30 Year Old Generation, Generation, Go to hospital 13% 13% and shopping, Commuting, 16% 21%
Work （ ） Traveling, 17% transport , 50 Year Old 40 Year Old 6% Generation, Generation, Work（road 33% 35% Work ） （other）, management , 26% 10% 63％ 81％ Respondents: 429 Respondents:Respondents: 473 473
[ 15 ] Questionnaire survey results on the usefulness of visibility forecast information provided How satisfied are you with the services provided by the Snowstorm Visibility Information System? Website for PCs Website for smartphones Dissatisfied 2% Very dissatisfied 0% Dissatisfied 4% Website for smartphonesVery dissatisfied Somewhat 0% dissatisfied 10% Very Somewhat Very satisfied dissatisfied 10% satisfied 13% 11%
Somewhat satisfied Somewhat 29% Satisfied satisfied 46% 32% Satisfied 43%
88％ 90％ Respondents: 259 Respondents: 263
[ 16 ] Questionnaire survey results on almost Change behavior visibility forecast information provided How likely is it for you to change your schedule or travel plans when poor visibility of less than 200 m is predicted by the Snowstorm Visibility Information System?
Poor visibility of 200 m or less has never been predicted in the forecast area. 3% Breakdown
I always or often keep my travel I changed my departure plans or schedule unchanged. 60% 19% time. I refrained from going out 59% or traveling. I always or often change my travel plans or schedule. I changed my route. 40% 79% I brought a shovel and 22% warm clothing. I canceled my driving plans Respondents: 448 7% and used public transport.
Other 4%
0% 20% 40% 60% 80% Multiple answers (Respondents 352) Excluding two respondents who gave no answers
[ 17 ] Segmenting for carrying out a cross-tabulation
We do cross-tabulation of the questionnaire.z The attributes of the respondents I be classified as follows.
Other, 4% Use classification for cross-tabulation classification Purpose of the questionnaire Go to hospital and shopping, Commuting, Commuting Commuting 16% 21% Work Work（transport） Work Work （ ） Traveling, 17% transport , （road management） 6% Work（other） Work（road Work ） Private Traveling （other）, management , 26% 10% Going out shopping and go to hospital
Other Respondents: 429
[ 18 ]
Of the respondents whose main purpose in accessing the website is to check on snowstorms before private, many canceled their travel plans.
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
classification Purpose of the questionnaire Commut通勤 77% Poor visibility of 200 m or less has23% never been predicted Commuting -ing Commuting in the forecast area. 3% （WorkN=95 ） Work（transport） I always or often keep my travel Work plans or schedule unchanged. 19% Work 仕事 （road management） 77% 23% （N=184） Work（other） I always or often change my Private Traveling travel plans or schedule. 79% Going out shopping and go Private私用その他 88% 12% （ ） to hospital Respondents: 448 N=154 Other
The behavior and the schedule are changed or often changed. The behavior and the schedule are not changed or often changed.
[ 19 ] Questionnaire survey results on the usefulness and response to information E-mail service How satisfied are you with the How did you make use of the e-mail delivery services? e-mail information? Very Didn’t make use of the information Dissatisfied dissatisfied Very received via e- Other. 1% Checked the 1% 2% satisfied information mail. 1% received via e- Website for smartphones Somewhat 13% mail alone. 8% dissatisfied 7% Visited the Snowstorm Referred to the Visibility Somewhat information Information received via e- website for satisfied mails in making detailed 33% travel plans. information. 27% Satisfied 46% 44% Checked weather warnings and other information. 63％ 17% Respondents: 259 ％ Respondents: 88 263 [ 20 ] Summary With an aim of supporting drivers' decision-making during snowstorms, the authors conducted tests by providing road users with snowstorm visibility information. It was confirmed that the information provided was useful as summarized below:
The result a lot of people of the questionnaire was Good with this website
The results of a questionnaire survey showed that users of the Snowstorm Visibility Information System change their travel plans by referring to the information on this website.
The results of another questionnaire survey showed that users of the e-mail delivery service actively seek related information after receiving e-mails about poor visibility [ 21 ] Thank you for your kind attention