Post on 01-Nov-2014
description
Weather
Lars Böcker Sofia Thorsson
& Cycling
• Exis;ng studies lack a>en;on for dura;ons • Exis;ng studies have meteorological shortcomings:
– Assumed linear rela;onships
– Thermal condi;ons are only analysed by air temperatures
– Weather parameters are oFen singled out
– Need for analysing the integrated effects of weather
Background
Methods
N A$ri'on
Wave 1: Summer 950
Wave 2: Autumn 826 -‐13,1%
Wave 3: Winter 718 -‐13,0%
0
5
10
15
20
25
-10
0
10
20
30
40
Prec
ipita
tion
in m
m /
win
d sp
eed
in m
/s
Max
imum
air
tem
pera
ture
in ˚C
Wind speed (m/s)
Precipitation
Ta_max (observed)
Ta_max (1980-2010)
August September October November December January February
Wind Speed
Precipitation
Ta(max), observed
Ta(max), 1980-2010
Snow Cover
Methods
0
5
10
15
20
25
-10
0
10
20
30
40
Prec
ipita
tion
in m
m /
win
d sp
eed
in m
/s
Max
imum
air
tem
pera
ture
in ˚C
Wind speed (m/s)
Precipitation
Ta_max (observed)
Ta_max (1980-2010)
August September October November December January February
Wind Speed
Precipitation
Ta(max), observed
Ta(max), 1980-2010
Snow Cover
Methods
Descrip;ves: modal split
0%
20%
40%
60%
80%
100%
Ta (max)
Bicycle Walking Public transport Car
20-‐25˚C 100
0
%
Descrip;ves: modal split
0%
20%
40%
60%
80%
100%
Ta (max)
0%
20%
40%
60%
80%
100%
Precipitation (sum)
0%
20%
40%
60%
80%
100%
Ws (avg.)
Bicycle Walking Public transport Car
100
0
% 20-‐25˚C
Descrip;ves: cycling frequencies
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4 Ta (max)
20-‐25˚C
Bicycle as main mode
Bicycle as access/egress to public transport
Descrip;ves: cycling frequencies
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4 Ta (max)
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
Precipitation (sum)
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
Ws (avg.)
20-‐25˚C
Bicycle as main mode
Bicycle as access/egress to public transport
Descrip;ves: cycling dura;ons
0
5
10
15
20
25 Ta (max)
Bicycle as main mode
20-‐25˚C
25
0
5
10
15
20
min.
Descrip;ves: cycling dura;ons
0
5
10
15
20
25 Ta (max)
0
5
10
15
20
25
Precipitation (sum)
0
5
10
15
20
25
Ws (avg.)
Bicycle as main mode
25
0
5
10
15
20
min.
20-‐25˚C
Mul;variate analysis
Meteorological a$ributes (Daily level) -‐Maximum Ta -‐Maximum Tmrt -‐Maximum PET -‐Precipita;on sum (between 6 and 12 a.m.) -‐Wind speed (between 6 and 12 a.m.)
Cycling behaviour -‐Mode choice -‐Cycling frequencies (per person per day) -‐Cycling dura;on (total per person per day)
Mul;variate analysis Spa'otemporal a$ributes -‐Residen;al environment -‐Weekday/weekend -‐Morning peak/ evening peak/off-‐peak day;me/offpeak nigh`me -‐Daylight/darkness
Personal a$ributes -‐Age, gender -‐Ethnicity -‐BMI -‐Educa;on -‐Weekly work dura;on -‐Working hour flexibility -‐Bicycle ownership -‐Public transport card Household a$ributes -‐Household type -‐Car ownership -‐Household income -‐Garden/balcony size -‐House air-‐condi;oning AAtudes/habits -‐Urban/countryside person -‐Environmental concern -‐A`tude towards seasons
Meteorological a$ributes (Daily level) -‐Maximum Ta -‐Maximum Tmrt -‐Maximum PET -‐Precipita;on sum (between 6 and 12 a.m.) -‐Wind speed (between 6 and 12 a.m.)
Cycling behaviour -‐Mode choice -‐Cycling frequencies (per person per day) -‐Cycling dura;on (total per person per day)
Trip a$ributes -‐Trip purpose (work/study, errands, social visit, leisure) -‐Type of trip (rou;ne, planned, impulsive
Three thermal parameters
Air temperature (Ta)
Air temperature (Ta) Mean Radiant Temperature (Tmrt)
Three thermal parameters
Air temperature (Ta) Mean Radiant Temperature (Tmrt)
Physiological Equivalent Temperature (PET) à Air temperature à Radiant heat load à Wind speed à Humidity
Three thermal parameters
14 August 2012 - semi-cloudy day no precipitation, mean wind speed 1.3 m/s (1.1m)
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
Tem
pera
ture
C
Ta Tmrt PET
Ta
Tmrt
PET
Three thermal parameters
Weather change: from clear and calm to cloudy and windy
Results: mode choice Ta model Cycling v car Walking v car Publ. transp. v car
Ta bell-‐shaped 24˚C + Wind speed -‐ Precipita;on sum -‐ -‐
Tmrt model Cycling v car Walking v car Publ. transp. v car
Tmrt bell-‐shaped 52˚C ++ -‐ Wind speed -‐ Precipita;on sum -‐ -‐
PET model Cycling v car Walking v car Publ. transp. v car
PET bell-‐shaped 30˚C +++ Precipita;on sum -‐ -‐ -‐
Mul'nomial LOGIT model (clustered S.E.)
Wald Chi2 = 3176
Wald Chi2 = 3242
Wald Chi2 = 3173
Results: cycling frequencies
Tmrt Model # Cycling trips / person / day
Tmrt bell-‐shaped 52˚C +++ Wind speed
Precipita;on sum -‐ -‐ -‐
PET (model) # Cycling trips / person / day
PET bell-‐shaped 33˚C +++ Precipita;on sum -‐ -‐ -‐
Nega've Binomial model (clustered S.E.)
Ta Model # Cycling trips / person / day
Ta bell-‐shaped 24˚C +++ Wind speed
Precipita;on sum -‐ -‐
Wald Chi2 = 407
Wald Chi2 = 428
Wald Chi2 = 415
Results: cycling dura;ons Ta (model) Cycling hours / person / day
Ta bell-‐shaped 24˚C +++ Ws -‐ -‐ -‐ Precip. -‐ -‐
Tmrt Model Cycling hours / person / day
Tmrt bell-‐shaped 52˚C +++ Ws -‐ Precip. -‐ -‐ -‐
PET (model) Cycling hours / person / day
PET bell-‐shaped 31˚C +++ Precip. -‐ -‐ -‐
TOBIT model (clustered S.E.)
Wald Chi2 = 235
Wald Chi2 = 244
Wald Chi2 = 240
Summary • Thermal condi;ons have non-‐linear bell shaped effects on cycling
• The PET and Tmrt models perform be>er than the Ta models
• Precipita;on and wind have nega;ve linear effects on cycling • Exchange mostly between cycling and the car, less for other modes
• Effects on dura'ons are stronger than on frequencies • Effects are stronger for leisure trips than for u;litarian trips
Conclusion • Cycling is most sensi;ve to weather
• Complexity weather and mobility
• Non linear rela;onships, op;mums and thresholds
• Combining parameters (Tmrt or PET) be>er than singling out (Ta)
• Nevertheless Ta is s;ll very useful: – widely available – easily interpretable – compa;ble to weather forecasts and climate change
Thank you! Böcker & Thorsson (2013) Integrated weather effects on cycling shares, frequencies and dura;ons in Ro>erdam, the Netherlands
Exis;ng knowledge on weather and transport mode choices:
Böcker, Dijst & Prillwitz (2013) “Impact of weather on travel behaviour in perspec;ve: a literature review”, Transport Reviews
L.Bocker@uu.nl
Funded by: