Changing Travel Behaviour Phil Goodwin Centre for Transport and Society, UWE Bristol
Mar 27, 2015
Changing Travel Behaviour
Phil GoodwinCentre for Transport and Society, UWE Bristol
‘Changing’ is ambiguous
• ‘Changing’ as a description of what is happening, whether we will it or not
• ‘Changing’ as an active intervention, with intent to make things different
An axiom: travel behaviour does change, and therefore it can be changed
Cars & Traffic in GB
0
10
20
30
1950 1960 1970 1980 1990 2000
Car
s, m
illio
ns
0
100
200
300
400
500
600
Tra
ffic,
bill
ion
vkm
CARS +1177%
TRAFFIC +815%
In one lifetime, car ownership and use have changed enormously
The change has been to establish a domination by car
Passenger Travel in GB, billion pkm
0
200
400
600
1950 1960 1970 1980 1990 2000
BUS - 50%
CAR +993%
CYCLE - 83% RAIL +26%
Trends show the net effect of a churn: but individuals change in either direction
Proportion of people in households whose car ownership increased or reduced
0%
10%
20%
30%
40%
50%
60%
70%
80%
Cars reduced No change Cars increased Net increase
Source – 1988 and 1991 South Yorkshire Panel surveys
Trip rates also can increase or reduce
% of people in groups with similar numbers of trips per person
0%
10%
20%
30%
40%
50%
60%
same band increase decrease
Source – London Panel Survey Spring and Autumn 1976
All the time, people are changing the method of transport they use
Main Commuting Mode, % of commuters
2.40.90.942.40.21.40.21.110
4.31.21.953.40.41.80.41.29
5.61.32.658.70.52.70.41.68
6.51.73.563.90.73.60.62.07
7.42.34.567.80.74.40.92.56
8.52.85.370.80.95.41.22.95
10.63.47.273.41.56.71.63.44
12.93.99.476.32.28.41.94.93
16.46.213.979.33.111.52.65.62
22.19.425.083.14.716.53.97.81
at least n years
9.73.37.466.91.56.21.43.3ave. yr
walkcyclecar pass.
car driver
m’cycbustuberail
Even relationships change(eg between car ownership and age)
Household Car Ownership by Cohort
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87
Age of head of household
Ca
rs p
er
ho
useh
old
1961-65
1951-55
1941-45
1931-35
1921-25
1911-15
1901-05
1970
1995
And between car ownership and income
Relationship between Car Ownership & Income
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 50 100 150 200 250 300 350 400
Total weekly expenditures, 1989 £
Car
s p
er h
ou
seh
old
Declining Income
Rising Income
Declining Income
Rising Income
1911 - 14
1961 - 65
1931 - 35
Policies have big effects(though more complex than intended)
• Increases in road capacity induce traffic• And capacity reduction reduces traffic• Price changes (fuel, fares, congestion
charging, vehicles) all influence traffic• ‘Soft’ measures change individual
behaviour substantially and can reduce traffic if supported by other policies
• Park and ride reduces traffic in the centre (but may increase it elsewhere)…
Induced traffic: SACTRA, 1994
an average road improvement induced roundly 10% of the base traffic in the short run, and about 20% in the long run, and there were some schemes with induced traffic at double this level.
the biggest levels of induced traffic were on the alternative routes that the schemes were intended to relieve.
And the opposite? – Cairns et al 1998
Practical experience of capacity reduction
Changes in traffic
-150 -130 -110 -90 -70 -50 -30 -10 10 30
Average: -22%
Central case: -11%
PRICE?Elasticities wrt Fuel Price per Litre
Literature Review
-0.30-0.10traffic volume
-0.60-0.25fuel consumption
long termshort term
Fares affect patronage
Dynamic Bus Fare Elasticity
-1
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0 1 2 3 4 5 6 7 8 9 10
Years following fare change
Ela
stic
ity
-0.88 -0.88-0.84
-0.6
-0.4
-0.86 -0.87
-0.81
-0.75
Short run (1-year)
Long run
-0.9
Effect of soft measures on individual choices, if induced traffic prevented
• 11% reduction in national traffic volume
• 21% reduction in urban peak period traffic (13% off-peak)
• 14% reduction in non-urban peak traffic (7% off-peak)
Park-and-ride in 9 citiesOverall Traffic Effects per Intercepted Car
-10
-5
0
5
10
15
20
25
30
35
Brig
hton
Cam
brid
ge
Cov
entr
y
Nor
wic
h
Ply
mou
th
Rea
ding
Shr
ewsb
ury
Yor
k
aver
age
km
urbanextra-urbannet
How fast does behaviour change?
The early research:Frequency of life events enabling choice
Conclusion
Travel behaviour is very much more volatile and changeable than is often thought, significantly sensitive to transport policy (whether intended or not) and a decision to 'leave behaviour alone' simply does not exist. Behaviour does and will change, and everything that Government chooses to do, or chooses not to do, has an impact on these changes. The scope for making things better (or, indeed, worse) by changing behaviour is substantial, and unavoidable…