ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

G. SCHUITEMA, L. STEG, C. VLEKARE PRICING POLICIES EFFECTIVE TO CHANGECAR USE?

Geertje SCHUITEMA

Linda STEGCharles VLEK

Department of Psychology 	
University of Groningen 	Groningen, The Netherlands

Lecturer, Department of Psychology
University of Groningen
Groningen, The Netherlands

Professor Emeritus, Department of Psychology
University of Groningen
Groningen, The Netherlands(Received December 21, 2006)

The effectiveness of transport pricing was considered in two studies regarding intended changes in car use if pricing policies
were implemented. In the first study, respondents kept a travel diary for four days, noting all their car trips. Next, they indicated to what
extent various pricing policies would affect the trips noted in the diary. In the second study, respondents indicated their intention tochange their car use for various types of trips if pricing measures were implemented. By using tailored questionnaires, accurate feedback was provided about the financial consequences of pricing for each respondent separately.
Results revealed that under pricing policies most people did not intend to change their car use. Pricing policies were relatively
more effective when prices increased significantly. Especially visiting and shopping trips were affected, while commuting trips werehardly affected. Moreover, respondents were most likely to reduce their car use for short trips, which are an important source of CO2
emissions and local air pollution.
Key Words: Pricing policies, Behavioural changes, Car use, Trip motive, Price level

1. ARE PRICING POLICIES EFFECTIVE IN
CHANGING CAR USE?
It is widely believed that negative impacts of car
use can and should be considerably reduced 1-4, for instance through sophisticated transport technologies.
However, technical measures are not sufficient to reduce
all negative impacts, because their environmental benefits
are often overtaken by increasing car use. Therefore, behavioural changes to reduce car use are necessary as well.
Various strategies for changing car use have been proposed 5-8, among which is transport pricing. In this paper,
factors that may affect the effectiveness of such pricing
policies are examined.
First, we consider which behavioural changes may
occur when transport pricing is implemented (e.g., changes in transportation mode, route, or destination; researchquestion 1 (RQ1)). Second, because some trips are likely
to be more easily adapted than others 9, we consider howtransport pricing would affect various types of trips (research question 2 (RQ2)). Third, the effectiveness of different types of transport pricing is examined; for importantcharacteristics of pricing policies specific hypotheses areformulated below.
Various policy features may affect the effectivenessof transport pricing on car use. First, a distinction can bemade between push and pull measures. Push measures
are aimed at directly reducing the attractiveness of caruse. In case of transport pricing this implies an increasein the costs of car use, for example increasing fuel taxes.
Pull measures are aimed at increasing the attractivenessof alternative transportation modes, and, consequently, atmaking car use relatively less attractive, for example bydecreasing costs for public transport (PT). Because of its
many individual advantages (e.g., speed, flexibility andcomfort), car use is preferred by the vast majority, evenby people who mainly use alternative modes of transportation10. Therefore, it is not likely that pull measuresalone can significantly decrease the relative attractiveness of car use, and thus car use itself. Indeed, a decreasein the costs of using PT appeared not to affect car use:
new bus passengers were mainly those people who used
to walk or cycle11-12. Therefore, our first hypothesis isthat push measures are more effective in changing people’s car use than pull measures (Hypothesis 1).
Second, price level is very likely to affect car use: itis expected that pricing policies are more effective when
price changes are larger (Hypothesis 2).
Finally, the allocation of revenues from push measures may affect the effectiveness of transport pricing.
Allocating revenues to benefit car users (e.g., by decreasing car-related taxes) appears to be more acceptable than
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Efforts To reduce CO 2 in the transportation Field

allocating revenues to general public funds13-14. However, allocating revenues to car users undermines the initial
purpose of the measure, that is, increasing the costs of caruse. Therefore, we hypothesize that transport pricing isless effective in changing car use when revenues are ‘returned to car users’ instead of being allocated to generalpublic funds (e.g., by decreasing labour taxes; Hypothesis 3).
Most psychological studies on the effectiveness oftransport pricing policies do not measure actual changes
in car use, but only the intention to do so. Intentions tochange behaviour do not necessarily go along with actual
behavioural changes, because people may not think
through their consequences in much detail. The studies
presented below also focus on subjects’ intentions tochange car use. Special care was taken to derive valid
judgements on respondents’ intentions to change car use.
First, financial consequences of transport pricing policies
for individual car users were determined. Second, respondents reported their current travel behaviour in detail, and indicated to what extent transport pricing policies
would affect these trips.

2. STUDY 1
In Study 1 we examined the effectiveness of two
significant characteristics of transport policies on people’s intention to change car use: Push versus pull measures (Hypothesis 1) and small versus large price changes(Hypothesis 2). Furthermore, it was examined which behavioural changes are likely to occur (RQ1). Finally, effects of pricing on 12 different types of trips were
examined (RQ2).
2.1 Method
2.1.1 Sample
The sample consisted of 58 respondents. Respondents possessed a driving licence and had access to a car.
The sample was representative for the Dutch population15, except for mean age, which was a bit higher than
average. This was due to the fact that only car drivers(with minimum age 18) were interviewed.
2.1.2 Diary
Respondents registered all their car trips (‘from A
to B’) in a travel diary from Thursday to Sunday. To facilitate respondents to recall specific trips for the laterinterview (see next Section), for each trip respondents
noted departure time, starting point, trip length (in kms),
trip purpose, arrival time and place, and whether they
were the driver or passenger. The following trip purposes
were distinguished: (1) returning home, (2) visiting
someone, (3) work or education, (4) business, (5) goingout, (6) sports, (7) recreation, (8) shopping (except forgroceries), (9) bringing or picking up somebody, (10)holiday, (11) grocery shopping, and (12) other. For eachday, a maximum of 8 trips could be registered. At the endof the diary, respondents indicated their gender, age, income, education, and household type.
2.1.3 Interview
Within a week after completing the diary, respondents were interviewed at their home in person or by telephone. Respondents were asked to indicate how anincrease in fuel prices (push measure) and a decrease of
PT fares (pull measure) would affect the car trips registered in the travel diary. Half of the respondents were firstpresented with the push measure, the other half first evaluated the pull measure. Between three subgroups, bothmeasures varied systematically among a low, middle andhigh price level. For the push measure, fuel prices would
increase by 5, 10 or 20 cent per litre. For the pull measure, PT fares would decrease by 10, 20 or 50%. The total
study design is given in Table 1.
For each trip recorded in the travel diary, respondents indicated whether and how they would change thistrip if the push or pull measure, respectively, would be
implemented. For the pull measure the response categories were (1) no change (i.e., sticking to the car), orchanging transportation mode to (2) bus, (3) train, (4)tram, or (5) subway, instead of the car. For the push measure, these categories were extended with (6) going by

Table 1 Design and number of respondents per condition
Push measure
increase of fuel prices
Price level

N

Pull measuredecrease of PT fares

N

low

5

cent increase

22

10% decrease18

medium10

cent increase

18

20% decrease

21

cent increase

18

50% decrease

19

high

20

Note: Respondents were randomly assigned to a ‘push’ and ‘pull’ condition.

22

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ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

2.2 Results
2.2.1 Which car trips were made?
Altogether, respondents registered 777 trips during
four days (Fig. 1). Unsurprisingly, most trips were madeto return home from various destinations. Next, mosttrips were made for grocery shopping, work or education,and visiting. Trips to go out, holiday and recreation trips
were infrequent. This distribution corresponds fairly wellwith the pattern of car trips made by the general Dutch
population in 200316.
returning homework/education
grocery shopping
visiting
otherbringing/picking up
someoneshopping
business
sportsgoing out
recreation

were most likely to be replaced. Car trips that respondents hardly intended to change were visiting trips, trips
to go to work/ education, bringing/ picking up someone,business trips and “other” car trips. Since car trips for
sports, recreation, going out, and holidays were hardly
made (Fig. 1), it is not surprising that these types of trips
were infrequently replaced.
increased fuel prices
reduced PT fares
returning homework/education
grocery shopping
visiting
Trip purpose

foot or (7) bicycle, (8) do not make the trip at all, (9)combine this car trip with other trips, or (10) change thedestination of the car trip.

G. SCHUITEMA, L. STEG, C. VLEK

otherbringing/picking up
someoneshopping
business
sportsgoing out
recreation
holiday
0

5

10

15

20

Number of changed trips

holidaysFig. 1 Distribution of car trips as reported in travel dia­ries over 4 days, for 12 different trip pur­poses

2.2.2 Do people intend to change their car trips?
Of all car trips made (across price levels), respondents intended to change 2.6% (i.e., 20 car trips) if PT
fares would be reduced. Increasing fuel prices would affect 5.3% of all car trips (i.e., 41 car trips). However, increasing fuel prices especially resulted in a reduction ofshort trips: 5.3% changed trips and 2% reduction of car
kilometres; whereas a decrease in PT fares especially affected longer car trips: 2.6% changed car trips and 7.3%
reduction of car kilometres. The overall difference between the number of changed car trips for push versus
pull measures was not statistically significant (t (57) =-3.4, p = 0.17)17.
2.2.3 Which types of car trips are changed?
As Figure 2 shows, respondents intended, acrosspolicies and price levels, to change car trips to returnhome most often. This is not surprising, since a car trip toreturn home is linked to an outgoing car trip serving another purpose. Next, car trips to go (grocery) shopping

Fig. 2 Number of intended car trip changes when fuelprices increase or PT fares decrease, for 12 trip
purposes, across 3 pricing conditions

2.2.4 Does price level affect people’s intention tochange their car use?
Figure 3 shows that the higher the increase in fuelprices, the more respondents intended to replace car trips(Fpush (2, 55) = 4.30, p < .05)18. As part of the ANOVA,
contrast tests were conducted to examine the differences
between high, medium and low price changes separately.
An increase of fuel prices with 20 cent per litre led tomore changes in car use than an increase with 10 centper litre (t (18) = 2.93, p = .01). No significant difference
was found between increases of 20 versus 5 cent per
litre (t (34) = 1.02, p = .31). No significant difference wasfound between a 5 cent price increase and a 10 centprice increase either (t (17) = -1.94, p = .07).
In case of a reduction of PT fares, people tended toreplace more car trips if fares were reduced more strongly (Fpull (2, 55) = 2.55, p = .09). Especially when PT fares
were reduced by 50%, the tendency was that more car
trips were replaced compared to a reduction of 20% (t(19) = 1.77, p = .09), but not compared to a fare reduction
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Efforts To reduce CO 2 in the transportation Field

respondents intended to travel more often by train and, toa lesser extent, by bus instead of by car.

30

Number of replaced car trips

25

2.3
20
15
10
5
0
low

mediumhigh

Price level
increased fuel prices(5, 10 and 20 €cent)reduced PT fares(10, 20 and 50%)

Fig. 3 Total number of replaced car trips of respondents
for increased fuel prices and reduced PT fares
for low, medium and high price levelof 10% (t (22) = 1.51, p = .15). No significant difference
was found for the number of replaced car trips between a
10% and 20% reduction of PT fares (t (26) = -.57, p =.57)19.
2.2.5 How do people intend to adapt their car trips?
Overall, most respondents intended to cycle or walk
more often instead of driving their car when fuel prices
would increase (Table 2). A few respondents indicated touse the train or to stop making the trip at all when fuelprices would increase. When fares of PT were reduced,
Table 2 Replacements of car trips when fuel prices
increase or PT fares reduce
Replace car trip byNumber of trips changed
increase fuel prices decrease PT fareschangetransportmode to

a

bus

0

6

train

2

12

tram

0

0

subway

0

0

walk

4

n.a.a

cycle

30

n.a.

not make trip at all

5

n.a.

combine trips

0

n.a.

change destination

0

n.a.

total

41

20

n.a. = not applicable

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Discussion
In general, visiting and shopping car trips would be
most frequently changed, whereas commuting car trips
would be hardly changed (RQ1). When fuel prices wereincreased, people indicated to replace mostly shorter car
trips by walking or cycling. When PT fares were decreased,mostly longer car trips would be replaced by trips made bytrain or bus (RQ2). Respondents tended to replace more
car trips when fuel prices are increased than when PT fares
are decreased. However, this difference was not statistically significant (Hypothesis 1), which may be due to thesmall sample size. Furthermore, the results indicate that alarge price change would be more effective than medium
and low price changes (Hypothesis 2).

3. STUDY 2
In Study 2, people’s intention to change car use was
examined when two types of kilometre charge were implemented. Changes in car use (RQ 1) were considered
for three different trip motives (i.e., commuting, visitingand ‘other’ trips; RQ 2). Furthermore, the effect of pricelevel (Hypothesis 2) and revenue allocation (Hypothesis
3) were examined.
3.1 Method
3.1.1 Sample
A computerized questionnaire survey was conducted among 562 Dutch car users selected from a larger
telepanel of a Dutch marketing research institute. Of thetotal sample, 288 respondents were car users who experienced road congestion when travelling to work at least
twice a week. Compared to the general Dutch car user, amajority of these drivers was male and had a relatively
high income and educational level, which is typical for
Dutch ‘congestion drivers’20. The other 274 respondents
were randomly selected from the total panel, provided
that they had a driving licence and had access to a car.
This group was representative for the Dutch population15,
except that the average age was somewhat higher, because the minimum age of Dutch car users is 1821.
3.1.2 Procedure and design
Each respondent first evaluated a flat and then avariable kilometre charge. For both the flat and variablekilometre charge 6 versions were made, varying in price(3 levels) and revenue allocation (2 levels). Each respon-

ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

dent was randomly assigned to one version of the flat and
one version of the variable kilometre charge. Below, bothkilometre charges are described in more detail.
(1) Description of flat kilometre charge
The flat kilometre charge implied that car drivers had
to pay for each kilometre driven by car. The charge
could be either 3, 6 or 12 cents per kilometre, while
revenues were either used to reduce labour taxes or to
reduce costs of car use (see left part of Table 3). It
was made clear that the kilometre charge would bebudget-neutral: revenues to benefit car users were either used to abolish road taxes (low km price), abolish road taxes as well as taxes on car purchase (medium

G. SCHUITEMA, L. STEG, C. VLEKkm price), or abolish both these taxes as well as improving and building road infrastructure (high km
price). Next, the estimated cost increases for each respondent were shown by multiplying the respondent’s
annual kilometrage by the price level of the charge.
In case revenues were used to benefit car users, anestimation of the personal benefits was given as well,based on weight and fuel type of the car respondents
used most frequently (for the calculation of the benefits, see Appendix). Also, total costs minus benefits
were shown in case revenues were used to decrease
costs for car users.

Table 3 Design and number of respondents per condition for flat and variable kilometre charge
FLAT KILOMETRE CHARGEVARIABLE KILOMETRE CHARGE

Revenue use to
general public
funds

low
price
level

average
price
level

high
price
level

cent/kmbenefit car user

price

3

3

cent/kmrevenues

decrease labourtaxes

abolish road taxes

costs

annual kms*3

annual kms*3

benefits
total

N

n.a.
n.a.
101

see Appendix
costs -/-benefits
96

price

6

6

revenues

decrease labourtaxes

abolish road taxes
and taxes on carpurchase

costs

annual kms*6

annual kms*6

benefits
total

N

n.a.
n.a.
94

see Appendix
costs -/- benefits
91

price

12

revenues

decrease labourtaxes

abolish road taxes,
taxes on car purchaseand invest in roadinfrastructure

costs

annual kms*12

annual kms*12

benefits
total

n.a.
n.a.
88

see Appendix
costs -/- benefits
92

Revenue use to
general public funds

benefit car user

2 (o.r.h.b) versus 6 cent/km (d.r.h.c)decrease labour taxes

2 (o.r.h.) versus 6(d.r.h.)cent/kmannual kms*2 (o.r.h.)/annual kms*6 (d.r.h.)
n.a.
n.a.
96

annual kms*2 (o.r.h.)/annual kms*6 (d.r.h.)
n.a.
n.a.
96

4 (o.r.h.a) versus
12 cent/km (d.r.h.)decrease labour taxes

4 (o.r.h.a) versus
12 cent/km (d.r.h.)abolish road taxes and taxes
on car purchaseannual kms*4 (o.r.h.)/annual kms*12 (d.r.h.)
n.a.
n.a.
94

annual kms*4 (o.r.h.)/annual kms*12 (d.r.h.)
n.a.
n.a.
91

8 (o.r.h.a) versus 24 cent/km (d.r.h.)decrease labour taxes

8 (o.r.h.a) versus
24 cent/km (d.r.h.)abolish road taxes, taxes on
car purchase and invest inroad infrastructure

annual kms*8 (o.r.h.)/annual kms*24 (d.r.h.)
n.a.
n.a.
88

annual kms*8 (o.r.h.)/annual kms*24 (d.r.h.)
n.a.
n.a.
97

fin. conseq.acent/kmcent/kmfin. conseq.

cent/km12

cent/kmfin. conseq.

Nafin. conseq. = financial consequences; b o.r.h. = outside rush hours; c d.r.h. = during rush hours
Note: Respondents were randomly assigned to one of the conditions of the flat and variable kilometre charge.

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Efforts To reduce CO 2 in the transportation Field(2) Description of variable kilometre charge
The variable kilometre charge implied that higher
prices were applicable during rush hours than outside
rush hours (between 7.00 –9.00 a.m. and 5.00 –7.00
p.m.). Three price levels were distinguished: low (2cents/km outside rush hours versus 6 cents/km
during rush hours), medium (4 versus 12 cents),
and high (8 versus 24 cents). Again, revenues were
either used to reduce labour taxes or returned to car
users (see right part of Table 3). Once more, it wasmade clear that the kilometre charge was budgetneutral, implying that revenues used to benefit car
use were either used to abolish road taxes (low km
price), abolish road taxes as well as taxes on purchasing cars (medium km price), or abolish both thesetaxes as well as improve and building road infrastructure (high km price). Next, an estimation of the cost
increases was given. Since it was not known how
many kilometres respondents drove during rush
hours, total costs were indicated in case respondents
would drive exclusively during rush hours (annual
kilometrage was multiplied by km price during rush
hours) and in case respondents would never drive
during rush hours (annual kilometrage multiplied by
km price outside rush hours). Only when revenues
were used to benefit car users, an estimation of thebenefits for the respondents was shown, as based onweight and fuel type of their most-used car (see Appendix).
3.1.3 Questionnaire
A computerized questionnaire was designed to examine the effectiveness and acceptability of four transport pricing policies. Below, the measurement of theeffectiveness of the flat and variable kilometre charge aredescribed in more detail22-23.
(1) Part 1: Current travel behaviour
Respondents indicated fuel type (petrol, LPG or diesel) and weight category (light, middle or heavy vehicle) for the car they used most frequently. Moreover,they indicated their average annual car kilometrage
for private purposes (excluding business trips; M =19,068 km). Next, they indicated which percentageof this kilometrage was used for commuting (M =41.7%), visiting (i.e., go to see/ visit someone; M =26.5%) and ‘other’ trips (i.e., all car trips except forcommuting, business or visiting trips; M = 31.8%).
(2) Part 2: Effectiveness of flat kilometre charging
Respondents first evaluated the effects on their caruse of a flat kilometre charge. Only those who had
indicated before that they made one or more commuting car trips a week indicated their intention tochange their commuting car use if the flat kilometre
charge would be implemented. Subjects’ intention to

Table 4 Flowchart representing the measurement of subjects’ intention to change car use
Flat kilometre charge

yes
→

yes
→

no ↓

changecommutecar trips?

→

divide number ofchanged commute
car trips overalternative modes→ go tovisiting
car trips→

divide number ofchanged visiting
car trips overalternatives modes→ go to‘other car
trips

→

divide number ofchanged ‘other’ car
trips overalternative modes

yes→changevisiting
car trips?

yes
→

↓
no

no ↓
at least 1‘other’ car trip
a weekStep 3how many
commute car trips
would be changed
in 4 weeks?

↓
no

no ↓
at least 1
visiting car
trip a week?

Step 2yes→change‘other’ car
trips?
no ↓yes→presentation number of car trips made in 4 weeks(self-reported number of trips a week * 4; see also
Fig. 4)at least 1
commute cartrip a week?

Step 1

how many visiting
car trips would bechanged in 4
weeks?

how many ‘other’
car trips would bechanged in 4
weeks?

↓

Proceed with variable kilometre charge (following the same scheme)
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ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

3.2 Results
3.2.1 Do people intend to change their car use?
When the flat kilometre charge was implemented,
almost 11% of the respondents indicated they wouldchange their commuting car trips, while a significantly% of respondents intending tochange car trip

higher percentage of about 25% would change their visiting (t (315) = 5.7, p < .001) and ‘other’ car trips (t (369)= 5.9 p < .001; Fig. 4). For the variable kilometre charge,
the number of changed car trips did not differ for commuting, visiting, and ‘other’ purposes.
A paired t-test revealed that respondents intended
to change their commuting car trips more often in case ofa variable kilometre charge, compared to a flat kilometre
charge (t (392) = 6.5, p < .001). For visiting and ‘other’
car trips, no differences were found between the flat andvariable kilometre charge.
100

flat kilometre charge

80

variable kilometre charge

60
40
20
0

26

26

25

24

22

11
commuting trips

visiting trips‘other’ trips

Fig. 4 Percentages of respondents who intended tochange one or more commuting, visiting and‘other’ car trips per four weeks

3.2.2 How many car trips would be changed by respondents who intended to reduce their car use?
Figure 5 represents the percentages of car trips
changed in four weeks when the flat and variable kilometre charge would be implemented. Those who intended tochange planned to change approximately half of these
trips. Overall, respondents indicated to change mostly
visiting and ‘other’ car trips.
The variable kilometre charge appeared to be more
flat kilometre charge
variable kilometre charge

100% car trips changed in
4 weekschange car trips was measured in three steps (seeTable 4). Next, the same procedure was followed
for visiting and ‘other’ car trips. Again, these questions were presented only to respondents who had
indicated to make one or more visiting or ‘other’ car
trips a week.
First, respondents indicated whether or not theywould change their car trips when a flat kilometre
charge would be implemented ((1) yes, change car
use to avoid cost increase or (2) no, no change in car
trips)24. Only respondents who indicated to change
commuting trips (N = 395), visiting trips (N = 450)or ‘other’ car trips (N = 522) answered the more detailed questions about changes in these trips as explained below.
Second, respondents who had indicated to change
their car use, estimated how many trips they wouldchange for each purpose per 4 weeks. For this purpose, for each type of trip the self-reported numberof car trips per week was multiplied by 4. The computed total number of trips made in 4 weeks was presented to the respondents to ensure that respondents
would provide valid assessments, and to enable respondents to indicate small numbers of intended car
trip changes. On average, 17 commuting, 7 visiting
and 14 ‘other’ car trips were made in four weeks.
Third, respondents indicated how they would replace
the car trips that they intended to change. The alternatives were: changing transportation mode by using(a) PT, (b), non-motorized transport (e.g., walk, cycle), (c) other motorized transport (e.g., moped, motorcycle), (d) carpool, or (e) not making the trip at all.
For commuting car trips the options (e) ‘not making
a trip because of a reduction of working days’ and (f)‘working at home’ were added.
(3) Part 3: Effectiveness of variable kilometre charging
Respondents evaluated the variable kilometre charge
as described above. The questions and procedure
were identical to the scheme followed for the flat kilometre charge, with one exception: in the third step,
an additional alternative for intended changes in car
use was added, namely (g) ‘change travel times’,since this option is highly relevant in case of timedependent kilometre charging.

G. SCHUITEMA, L. STEG, C. VLEK

67

80
60

52

(N =45)58(N =119)72(N =114)(N =102)62

48(N =116)(N =125)40
200commuting trips

visiting trips‘other’ trips

Fig. 5 Percentage of changed commuting, visiting and‘other’ car trips made in 4 weeks by respondents
who intended to change their car use
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Efforts To reduce CO 2 in the transportation Field

effective than the flat kilometre charge in changing thenumber of visiting (t (62) = -2.2, p = .04) and ‘other’ car
trips (t (66) = -2.5, p = .01), while for commuting trips no
significant differences were found.
3.2.3 How do people change their car trips?
Respondents who intended to change their car use
would mostly switch to alternative transportation modes(notably PT and non-motorized transport; see Table 5)
when the flat kilometre charge would be implemented. In
this case, respondents rather frequently indicated to stopmaking visiting and ‘other’ car trips at all, whereas forcommuting trips this option was hardly chosen. Replacing car trips by other motorized transport was not chosenfrequently. For the flat kilometre charge, carpooling wasan alternative for almost 20% of the commuting trips,
whereas working at home was not often chosen as an alternative for commuting trips.
In case of a variable kilometre charge, respondents
who intended to change their car use would, for almost
half of these car trips change their travelling times. Also,
respondents expected to switch to other modes of transportation (i.e., using PT and non-motorized transport) as
well. Other motorized transportation as well as refraining
from making a trip were hardly an alternative. In case of
the variable kilometre charge, commuting car trips werehardly changed into carpooling or working at home.
3.2.4 Are changes in car use related to price level andrevenue use?
Chi-square tests25 were used to examine whether
revenue allocation and price level were related to respondents’ intention (yes or no) to change their commuting,visiting and ‘other’ car trips. Obviously, analyses were
only conducted for respondents who made these trips atleast once a week. Results are presented in Figures 6a, 6b,
7a, and 7b.
For the flat kilometre charge, more respondents intended to change their commuting trips when revenues
were allocated to decreasing labour taxes (16.8%) compared to when revenues were used to benefit car users(6%; 2 (1) = 11.30, p < .001). Revenue allocation was
unrelated to intention to change visiting ( 2 (1) = 2.61,
p < .106) and ‘other’ car trips ( 2 (1) = .96, p < .327).
The higher the price level of the flat kilometre
charge, more people intended to change their visiting car
trips ( 2 (2) = 9.97, p = .007). When the price level was
12 cent/km 33.8% people indicated to change their caruse, 28.3% when the price level was 6 cent/km, and18.1% when the price level was 3 cent/km. Price level
did not significantly affect the number of respondents
who intended to change their commuting ( 2 (2) = 7.73,
p < .155) and ‘other’ car trips ( 2 (2) = 3.71, p < .156).
In case of the variable kilometre change, revenue al­
location and price level did not affect respondents’ intention
to change their commuting ( 2revenue use (1) = 3.0, p <.332; 2price level (2) = 1.11, p < .572), visiting ( 2revenue use(2) = .96, p < .327; 2price level (2) = .90, p < .639) and‘other’ car trips ( 2revenue use (1) = .71, p < .399; 2pricelevel (2) = 2.35, p < .309).
3.3

Discussion
Results revealed that about 11% of the respondents
under a flat and 26% under a variable kilometre charge
would change their commuting car trips, while roughly
25% would change their visiting and ‘other’ car trips
when kilometre charging would be implemented. Of
those who intended to change their car use, most respondents would switch to other transportation modes, especially public or non-motorized transport (RQ1). For

Table 5 Percentage of changed car trips, divided over various alternatives for respondents who intended tochange their car trips when a flat and variable kilometre charge is implemented
N

Alternatives for changing car usechange travel mode to

Flat kmchargeVariable km
chargeanon-motorizedtransport

motorized
transport

not making
trip

changetravel times

work athome

carpool

commuting

45

31.7

32.3

9.5

0.5

n.a.a

6.5

19.5

visiting

119

17.6

44.5

9

28.8

n.a.

n.a.

n.a.

‘other’

125

13.3

64.8

1.8

19.9

n.a.

n.a.

n.a.

commuting

102

17.7

12.7

8.8

0.6

47.8

7.9

4.5

visiting

114

13.6

28

1.7

8.8

47.8

n.a.

n.a.

‘other’

116

14.1

28.9

1.5

8.2

47.3

n.a.

n.a.

n.a. = not applicable

28

PT

IATSS Research Vol.31 No.1, 2007

ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

G. SCHUITEMA, L. STEG, C. VLEK

100

benefit car user
decrease labour taxes

90
80
70
60
50
40
30
20
10
0
commutingvisiting% of respondents changing their car trips% of respondents changing their car trips

Flat kilometer charge
100

80
70
60
50
40
30
20
10
0
commuting‘other’Fig. 6a Percentage of respondents who intended tochange their commuting, visiting and ‘other’
car trips for two conditions of rev­enue allo­
cation, when a flat kilometre charge is imple­
mented3 €cent
6 €cent
12 €cent

90

visiting‘other’Fig. 6b Percentage of respondents who intended tochange their commuting, visiting and ‘other’
car trips for three price level con­ditions, whena flat kilometre charge is implemented

100

benefit car user
decrease labour taxes

90
80
70
60
50
40
30
20
10
0
commutingvisiting‘other’% of respondents changing their car trips% of respondents changing their car trips

Variable kilometer charge100

3 €cent
6 €cent
12 €cent

90
80
70
60
50
40
30
20
10
0
commutingvisiting‘other’Fig. 7a Percentage of respondents who intended tochange their commuting, visiting and ‘other’
car trips for two conditions of rev­enue allo­
cation, when a variable kilometre charge is
implemented

Fig. 7b Percentage of respondents who intended tochange their commuting, visiting and ‘other’
car trips for thee price level con­ditions, whena variable kilometre charge is implemented

visiting and ‘other’ car trips, some respondents wouldstop making these trips at all. In case of a variable kilometre charge, respondents’ also intended to change theirtravel times. This option was chosen for almost half ofthe trips that would be changed.
Respondents were likely to change more visiting or‘other’ car trips than commuting trips (RQ2). Those who

intended to change their car use would change approximately half of the number of trips usually made.
Hypothesis 2 was partially confirmed: higher pricelevels of the flat kilometre charge especially affected visiting trips, but not commuting and ‘other’ car trips. In
case of the variable kilometre charge, no effect of pricelevel on intention to change car trips was found.
IATSS Research Vol.31 No.1, 200729

Efforts To reduce CO 2 in the transportation Field

Hypothesis 3 was partially confirmed: more people
intended to change their commuting car trips when revenues of the flat kilometre charge were allocated to decrease labour taxes compared to when revenues wereused to benefit car users. However, revenue allocation did
not affect changes in visiting and ‘other’ car trips. Also,
for the variable kilometre charge, revenue allocation had
no effect on people’s intention to change car use.

4. GENERAL DISCUSSION
In line with Jakobsson, Fujii and Gärling26, it was
shown that when costs of car use increased (either by increased fuel prices or by kilometre charges), shopping
and visiting trips were affected most, whereas commuting trips were much less affected (RQ1). Instead of making trips by car, those people who changed their intended
car use generally chose to travel by other modes of transportation such as public transport, walking or cycling(RQ2). When a price increase might be avoided by changing travel times (which fits a variable kilometre charge),
this option was chosen most often. This is an interesting
result: changing travel times seems to be perceived as amore feasible option than other alternatives, probably because it requires relatively little effort.
We also examined how policy characteristics wererelated to changes in car use. First, it was expected thatpush measures, reducing the attractiveness of car use,would be more effective in changing car use than pullmeasures (Hypothesis 1). Although the average extent ofchanges in car trips were in line with this expectation,differences were not statistically significant, possibly due
to the relatively small sample size. Nevertheless, the results of Study 1 have some important implications. First,
it appeared that lowering public transport fares (a pullmeasure) mainly reduced (a small number of) longer car
trips. Second, an increase in fuel prices (a push measure)mainly resulted in a reduction of short car trips, whichwere often replaced by trips made by foot or bicycle. Despite the fact that the total kilometre reduction was rather
small, these changes may significantly reduce (urban)
traffic problems. Short car trips are often made in densely
populated areas, causing relatively high levels of air pollution and other nuisance. Consequently, push measures
may significantly contribute to improving local environmental quality.
Second, it was expected that large price changes
would be more effective than small price changes (Hypothesis 2). Results of Study 1 revealed that a high increase of fuel price resulted in more car-use changes than30

IATSS Research Vol.31 No.1, 2007

low and average fuel price increases. However, in Study
2 the influence of price level on the effectiveness of kilometre charging was less clear. As in Study 1, for a flat
kilometre charge more respondents intended to change
their car use when the price per kilometre would be high,but this was found for visiting trips only. For the variablekilometre charge, price level appeared not to influence
the effectiveness of the charge, which may have to dowith the fact that a small kilometre price already had
quite strong effects on car use; people could relatively
easily evade the measure by changing their travel times.
Thus, for some transport pricing policies small pricechanges may be rather effective, whereas for other policies, strong price increases may be needed to change caruse; this seems to depend on the ease of behavioural adaptations (e.g., changing travel times versus changing
transportation mode).
Hypothesis 3 was partly confirmed: in case of a flat
kilometre charge, more people indicated to change theircommuting car trips when revenues were allocated to decrease labour taxes compared to using revenues to benefit
car users (i.e., abolishing fixed car taxes and/or improving road infrastructure). However, for other types of trip
revenue allocation was not related to changes in car use.
For the variable kilometre charge, people’s intention tochange car trips appeared not to be related to revenue allocation.
In summary, the results of both studies revealed
that the effectiveness of transport pricing depends on
various policy-relevant factors. When the aim of pricing
is to reduce congestion, a variable kilometre charge may
well cause significant changes in the travel times of commuter car drivers. However, when the aim is to reduce
local air pollution or CO2 emissions, a variable kilometre
charge may be less effective, because the number of trips
will be hardly reduced. In that case, introducing overall
cost increases of car use (e.g., via a flat kilometre charge)
may be more effective, because this would primarily affect the number of short car trips which are especiallyburdening in densely populated areas.

REFERENCES
1. EU. Europe at a crossroads: The need for sustainable transport. Available on: http://ec.europa.eu/publications/booklets/
move/39/en.pdf. (2003).
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213.253.134.29/oecd/pdfs/browseit/9701011E.pdf. (2001).
3. UNEP. GEO 2000: Global Environmental Outlook 2000. London, Earthscan. (1999).
4. for an overview see Vlek, C. Societal management of sustain-

ARE PRICING POLICIES EFFECTIVE TO CHANGE CAR USE?

able transportation: International policy review and sociobehavioural recommendations. in T. Gärling and L. Steg (Eds.)
Threats to the quality of urban life from car traffic: Problems,causes, and solutions. Amsterdam, Elsevier. in press.
(2007).
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6. Marshall, S., & Banister, D. Travel reduction strategies: intentions and outcomes. “Transportation Research Part A: Policy
and Practice” 34: pp. 321-338. (2000).
7. Steg, L. Factors influencing the acceptability and effectivenessof transport pricing. in: J. Schade and B. Schlag (Eds.) Acceptability of transport pricing strategies. Oxford, Elsevier
Science. pp. 27-62. (2003).
8. Vlek, C. & Michon, J. A. Why we should and how we could
decrease the use of motor vehicles in the near future. “IATSS
Research” 15: pp. 82-93. (1992).
9. Loukopoulos, P., Jakobsson, C., Gärling, T., Meland, S. &Fujii, S. Understanding the process of adaptation to car-use
reduction goals. “Transportation Research Part F: Traffic
Psychology and Behaviour” 9: pp. 115-127. (2006).
10. Steg, L. Can public transport compete with the private car?
“IATSS Research” 27: pp. 27-35. (2003).
11. Claassen, A. & Kropman, J. Verkenningen tussen theorie en
praktijk. Over de bijdrage van de sociale wetenschappen aan
de beleidspraktijk op het gebied van mobiliteit (Explorations
between theory and practice. About the contribution of thesocial sciences to policy practices in transport). Nijmegen,Instituut voor Toegepaste Sociale Wetenschappen. (1995).
12. Deslauriers, B. C. & Everett, P. B. Effects of intermittent andcontinuous token reinforcement on bus ridership. “Journal ofApplied Psychology” 62: pp. 369-375. (1977).
13. Schade, J. & Schlag, B. Acceptability of urban transport pricing. Helsinki, VATT. (2000).
14. Verhoef, E. T. Economic efficiency and social feasibility in theregulation of road transport externalities. Amsterdam, Thesis
Publishers Amsterdam (PhD thesis). (1996).
15. CBS. Bevolking: kerncijfers (Population: Key figures). Available
on: http://statline.cbs.nl. (2005).
16. CBS. Mobiliteit per regio naar motief en algemene kenmerken(Mobility by region for motive and general features). Available
on: http://statline.cbs.nl. (2006).
17. A t-test was conducted to examine whether the average
number of replaced car trips differed for the push and pullmeasure. The t-value indicates the ratio of the mean difference to the standard error of this difference.
18. An one-way analysis of variance (ANOVA) was conducted to
examine the differences between the numbers of replaced
car trips for three price-level conditions. The F-ratio indicatesthe ratio of the between-group variance to the within-group(or error) variance.
19. Since variances were not equal for all price conditions, t-tests
that do not assume equal variances are reported. As a resultof unequal variances, combined with a small sample size, thepower of these t-tests is rather small, implying that is it lesslikely to find significant differences between price levels.
20. Bureau Goudappel Coffeng. Marktprofiel van een filerijder.
Eindrapport (Profile of a ‘congested’ car driver. Final report).
Deventer, Bureau Goudappel Coffeng. (1997).
21. Generally, no significant differences were found in the inten-

G. SCHUITEMA, L. STEG, C. VLEKtion to change car use between ‘congestion drivers’ and Dutch
car users in general. Therefore, differences between bothgroups are not reported below.
22. For more information about the other two transport policies
and the parts concerning acceptability we refer to Tillema, T.
Road pricing: a transport geographical perspective. Geographical accessibility and short and long-term behaviouraleffects. Utrecht, Utrecht University (PhD-thesis). (2007).
23. Ubbels, B.J. Road pricing: Effectiveness, acceptance andinstitutional issues. Amsterdam, Free University (PhD-thesis).
(2006).
24. For commuting trips a third response category was added,
because commuters may also increase their car use when
they expect kilometre charging to diminish congestion ((3)
yes, change car use by making more car trips). This category was not included in the analyses because only 0.4% of the
respondents were expected to do so in case of the flat, and
0.8% in case of the variable kilometre charge.
25. Chi-square tests were conducted to examine the distributionof the number of respondents for each price level and revenue
allocation. The χ2 indicates whether the frequencies percondition in the sample (observed frequencies) deviate fromthe frequencies that can be expected based on probability
calculations (expected frequencies) in the sample.
26. Jakobsson, C., Fujii, S. & Gärling, T. Effects of economic
dis­incentives on private car use. “Transportation” 29: pp.
349-370. (2002).

ACKNOWLEDGEMENTS
The authors thank Annemarie van Brussel, Majke Lüthi,Marian Smeelen and Monique Kalter for the data collection of thefirst study. Financial support of the NWO/Connect VEV projecton ‘A Multidisciplinary Study of Pricing Policies in Transport’ isgratefully acknowledged.

APPENDIX
Table to calculate benefits for car users when revenues of kilometre charges are used to abolish road taxes.
The numbers are based on the road taxes that were inplace in 2004.
Car weight /fuel type

PetrolDieselLPG

light (<1000 kg)

220

550

500

middle class (1000 – 1250 kg)

350

700

700

heavy (>1250 kg)

550

1100

1100

Calculation of the benefits for car users when revenues of kilometre charges are used to abolish road taxes
and taxes on the purchase of cars. The numbers are basedon taxes that were in place in 2004.
Car weight /fuel type

PetrolDiesellight (< 1000 kg)

520

1150

LPG
800

middle class (1000 – 1250 kg)

850

1400

1200

heavy (> 1250 kg)

1200

2000

1750

IATSS Research Vol.31 No.1, 200731