Portland State University Portland State University
PDXScholar PDXScholar
Civil and Environmental Engineering Faculty
Publications and Presentations
Civil and Environmental Engineering
2017
Impact of Last Mile Parking Availability on Impact of Last Mile Parking Availability on
Commercial Vehicle Costs and Operations Commercial Vehicle Costs and Operations
Miguel Figliozzi
Portland State University
Chawalit Tipagornwong
Portland State University
Follow this and additional works at: https://pdxscholar.library.pdx.edu/cengin_fac
Part of the Transportation Commons, and the Urban Studies Commons
Let us know how access to this document bene;ts you.
Citation Details Citation Details
Published as: Figliozzi, M., & Tipagornwong, C. (2017, April). Impact of last mile parking availability on
commercial vehicle costs and operations. In Supply Chain Forum: An International Journal (Vol. 18, No. 2,
pp. 60-68). Taylor & Francis.
This Pre-Print is brought to you for free and open access. It has been accepted for inclusion in Civil and
Environmental Engineering Faculty Publications and Presentations by an authorized administrator of PDXScholar.
Please contact us if we can make this document more accessible: [email protected].
Impact of Last Mile Parking Availability on
Commercial Vehicle Costs and Operations
Miguel Figliozzi
1
and Chawalit Tipagornwong
1
1
Department of Civil and Environmental Engineering, Portland State University. P.O. Box 751,
Portland, Oregon 97207-0751, USA. [email protected]
Abstract:
This research analyses how parking availability levels affect commercial vehicle
parking costs and operations in congested urban areas. Unlike passenger vehicles,
parking availability has an impact on route characteristics and commercial vehicle fleet
sizes. Hence, commercial vehicles parking costs cannot be captured solely by estimating
delays and/or the cost of parking fines. This research combines logistics, queuing, and
optimization models to study the impact of last mile parking availability on commercial
vehicle costs and operations. Scenarios are built to study the impact of parking
availability on typical less-than-truckload (LTL) and courier service costs. Results
indicate that parking availability levels do affect commercial vehicle costs and
operations significantly. The magnitude of the impacts is a function of customer and
route characteristics. The analysis of elasticity values indicates that a few variables
have a significant impact on commercial vehicle parking behaviour. In some cases,
productivity improvements like service time reductions may result in undesirable
changes in commercial vehicle parking behaviour.
Keywords: commercial vehicles; last mile; parking costs; economic analysis; elasticity
Journal Reference
!"#$"%&&"'()*(+*(,(-"./#%012%1#'(3*(456789*(:;./<=(%>(?/@=()"$A(B/0C"1#(+D/"$/E"$"=F(%1(
3%;;A0<"/$(GAH"<$A(3%@=@(/1I(J.A0/="%1@*(KL..$F(3H/"1(!%0L;M(/1(:1=A01/="%1/$(N%L01/$'(
7OM5'(P6QPO*(
Introduction
There is a growing awareness regarding problems associated with commercial vehicles
in congested urban areas. Efforts to increase downtown or neighbourhood livability can
result in costly restrictions. Typical restrictions include commercial vehicle bans at
certain times of the day, limited parking and/or loading and/or unloading zones for
commercial vehicles, commercial vehicle noise level limits (when loading and
unloading), commercial vehicles pollution constraints, and commercial vehicles size
limits. For example, in New York City commercial vehicle size, routes, and parking areas
are restricted for urban freight distributors and service providers (City of New York,
2013).
On-street parking spaces and freight loading zones (FLZs) are typically
insufficient during certain periods of the day in most dense and congested urban areas,
for example in the USA these urban areas include New York City, San Francisco, Los
Angeles, Boston, Chicago, and Washington D.C. News organizations frequently report
on the problems caused by double-parked commercial vehicles or the high parking fines
that delivery companies must pay (NBC News, 2006; Gordon, 2007; Halsey, 2013;
Hawkins, 2013; Berezin, 2014).
Although anyone that lives in a dense and congested city is familiar with the
problems associated to commercial vehicle parking there is limited research in this area.
In particular, there is scant research related to models that attempt to understand the
impacts of FLZ availability on commercial vehicles costs and behaviour. This study
addresses the following research questions: how does parking availability affect
distribution companies’ parking behaviour? and (ii) what are the key variables that
affect parking costs?
Next section discusses key aspects of the problem under study and presents a brief
literature review. Later sections present a modelling framework that includes queueing,
logistics, and cost optimization models. A case study that includes different delivery
services types is analysed and cost elasticity and break-even values are discussed. The
final sections discuss policy and managerial implications and summarize the main
conclusions that can be derived from this research effort.
Background and Brief Literature Review
When all parking spaces near delivery destinations are occupied, commercial drivers
prefer not to park away from the delivery destination (Pluvinet et al., 2012). Several
factors explain this preference. It is difficult to move bulky or heavy products over long
distances or across intersections even if the driver or delivery person is utilizing a hand
truck (Allen et al. 2000). In some cities or neighbourhoods, drivers may prefer to see their
vehicles to prevent theft and/or vandalism (Morris, Kornhauser and Kay, 1999). In
addition, parking away from the delivery points adds time per delivery and small delays
quickly become significant for drivers or companies that have to serve many customers
along the route (Figliozzi, 2007, Figliozzi & Tipagornwong, 2016).
When there is no parking available nearby the delivery point commercial drivers
may double park. If commercial drivers double park frequently, the cost of parking fines
can be substantial. For example in New York City, large delivery fleets including FedEx,
UPS, and the U.S. Postal Service paid $550 million in 2013 (Hawkins, 2013). Since
repeated double parking fines increase the final delivery cost, urban freight distributors
and service providers may raise service fees to customers in areas where deliveries or
pick-ups are more difficult. For example, UPS charges a surcharge in some congested or
difficult delivery areas (such as zip codes 10000 – 10292) of Manhattan, New York City
(United Parcel Service of America, 2015).
Previous research efforts have modelled parking availability by analysing a
parking demand-to-supply ratio that is defined as the ratio between parking demand and
parking supply rates. Some publications define the parking demand rate as a freight trip
generation rate multiplied by the average parking time; for example, Jaller et al. (2013)
studied off-peak-hour deliveries and evaluated commercial parking availability with the
parking demand-to-supply ratio at different times of day in New York City. The freight
trip generation rate has been traditionally estimated as a function of the number of
employees by type of industry, commercial sector, or land use (Fischer and Han, 2001).
The parking supply is defined as the number of parking spaces or FLZs. The literature
based on the analysis of empirical demand/supply data largely agree that at peak times
there is insufficient parking capacity in commercial districts and along urban arterials
(Wenneman, Habib, and Roorda, 2015) and even in neighbourhoods (Chen and Conway,
2016).
Another line of research has utilized simulation models (for example, Aiura and
Taniguchi, 2006 and McLeod and Cherrett, 2011) to study commercial vehicle parking
in urban areas. These models can accurately represent transportation networks and FLZs,
generate commercial vehicle trips and their parking time, and estimate commercial
vehicles delays. A recent model to analyse parking policies in specific locations combines
parking choice models and a traffic simulation models (Nourinejad, et al., 2014).
The third approach is a statistical model. For example, a statistical model (based
on queuing theory) has been used to study how personal or passenger parking demand
responds to pricing and parking availability in San Francisco (Millard-Ball, Weinberger,
& Hampshire, 2014). This type of modeling effort can be used to investigate the impact
of pricing on parking arrival rate, parking duration, and parking availability.
Unfortunately, there is no similar dataset that can be utilized to study the impacts of
pricing and parking availability on commercial vehicles. A previous paper by the same
authors was preliminary (conference proceedings) and did not include a discussion of
elasticity values and policy/managerial implications (Figliozzi & Tipagornwong, 2016).
Unlike previous research efforts, this research focuses on modelling parking
availability combining queuing models and logistical models based on continuous
approximations. Unique contributions of this research are the addition of real-world
routing constraints such as load capacity or route time durations, the analysis and
comparison of courier and less-than-truckload (LTL), and ranking the impact of logistics
and policy variables as a function of their elasticity values. Next section presents the
modelling framework integrating queuing and continuous approximations for long-term
logistic costs.
Modelling Commercial Parking
This research models parking availability utilizing queuing models. Routing constraints
are modelled utilizing continuous approximations. Service costs includes all the relevant
long-term (vehicle and driver) costs. Finally, all the models are integrated within an
optimization framework that can be utilized to determine the optimal number of
vehicles, vehicle type, and parking behaviour.
Parking availability
Convenient access is important for both consumers and carriers (Duran & Gonzales-
Feliu, 2012) hence the number of available parking spots is usually limited. Assuming
that there are (S) freight loading zones available on a first-come-first-serve basis and
that inter-arrival times and FLZ occupation times follow exponential distributions, a
M/M/S queuing model can be utilized. The expected probability of double parking
!
"
#
$ % &'
(
)
&
can be estimated as follows:
"#$ % &'( * +,"#&$ - ',+( * +,
.
#/01(
2
$3
"#$ * 4(
567
289
"#$ * 4( *
+
:
#/01(
2
$3
;
#/01(
5
'3
<
+
+,/0'1
567
289
Where
"#$ % &'(
: probability that all FLZs are occupied
N : number of commercial vehicles in the system
S : number of FLZs
/
: commercial vehicle arrival rate (vehicles per hour)
1
: commercial vehicle service rate (vehicles per hour)
P( N=0 ) = probability that all FLZs are empty
If a commercial driver waits when FLZs are fully occupied, the expected waiting
time of the driver can be estimated as follows:
=
>
*
"
?
#/01(
@
#/0'1(
'3#+,/0'1(
A
/
When a commercial driver waits until a FLZ is available, it is assumed that the driver
waits inside the vehicle and since the vehicle is never left unattended, the “waiting”
driver will not receive a parking fine.
When the driver double-parks a parking enforcement officer can issue a parking
fine. However, an illegally parked vehicle does not always receive parking fines. This
study models the expected probability of receiving a parking ticket or fine given that all
FLZs are occupied
B
C
&
as a function of service time (
D
E
) and the parking enforcement
cycle duration (
D
FG
). The inverse of
1
is the duration of the average parking zone
utilization or
D
E
.
&B
C
* &HIJKLKMNMDO
#
DMPQRD
S
$ % '
(
( *
D
E
D
FG
An average parking utilization level (
T
) is defined as the ratio of parking
demand to parking supply
&#T * &/0'1(
. Parking utilization and parking availability are
inversely related, low parking utilization
&#NJU&T(
is associated with high parking
availability or easiness to find empty loading zones.
Routing Constraints
Continuous approximations have been successfully used by many research efforts to
model urban distribution systems (Langevin, A., Mbaraga, P., and Cambell, J. 1996;
Daganzo C. 2005). This study utilizes a continuous approximation model successfully
used in the past (Figliozzi M. 2008; Figliozzi M. 2010) to estimate the average route
distance of commercial vehicles.
VW"&
#
V
(
* Q
X
Y,Z
Y
[
Y\;]I
^
Z
where VRP (V) = average distance travelled for a fleet of m vehicles (miles)
Q
X
&
= local service area coefficients
n = number of customers
m = number of routes
A = the size of a service area (km
2
)
I
^ = average distance between customers and a depot (km)
The following parameters are utilized to formulate long-term service costs.
_
`
*
aJbI&cMdDLYPR&Je&fRgMPNR&DOHR&M&#ZMNRd0DJbI(
a
`
* aJbI&cbILDMJY&Je&fRgMPNR&DOHR&M&#gJbId(
a
hij
* kLlMZbZ&DJbI&cbILDMJY#gJbId(
U
m
* \fRILnR&PbdDJZRI&cRZLYc&#NKo0dDJH(
D
E
* \fRILnR&dRIfMPR&DMZR&#ZMYbDR0dDJH(
f
i
`
* \fRILnR&dHRRc&Je&fRgMPNR&M&nJMYn&eIJZ&L&cRHJD&DJ&DgR&dRIfMPR&LIRL&#ZHg(
f
p
`
* \fRILnR&dHRRc&Je&fRgMPNR&M&IbYYMYn&MYdMcR&DgR&dRIfMPR&LIRL&#ZHg(
f
q
`
* \fRILnR&dHRRc&Je&fRgMPNR&M&IRDbIYMYn&DJ&DgR&cRHJD&#ZHg(
U
r
`
* _JLc&PLHLPMDO&Je&fRgMPNR&DOHR&M&#NKd(
Route duration and vehicle capacity constraints can be expressed as follows:
_
`s
* I
^
;
t
u
v
wx
yz
wx
v
wx
{
|
wx
}
h
wx
;I
^
a
`s
*
~
w
;
t
u
v
wx
yz
wx
v
wx
[
|}
h
wx
w
;
~
ƒ
w
;&Y
`s
D
E
`
;#+,O
`s
(
!
Y
`s
=
>
#T(
)
Z
`s
% Y
`s
<U
m
0U
r
`
&&&&&&&&&&„M †‡ „ˆ
a
hij
% a
`s
&&&&&&&&&&&
&&&&&&&&&&„M †‡ „ˆ
The binary variable
O
`s
indicates whether the vehicle double-parks (
O
`s
* +(
or waits for
parking (
O
`s
* 4(
. These equations estimate the length of a delivery tour that starts from
a depot, serves customers, and returns to the depot as well as tour duration. Average
parking utilization levels
T
and parking behaviour affect waiting time
=
>
&
and can
indirectly also affect fleet size when
a
`s
increases over the maximum tour duration.
Service Costs
Long-term service cost includes vehicle depreciation cost, energy/fuel cost, vehicle
maintenance cost, driver wage, driver annual costs, truck annual costs, and double-
parking fines. In the USA drivers’ annual costs include driver health insurance, social
security tax, Medicare tax, and pension/retirement; the truck annual costs include
vehicle registration and insurance. The following indices are utilized to formulate long-
term service costs.
Š
dRD&Je&fRgMPNR&DOHRd
Œ
* †&
dRD&Je&HLIQMYn&KRgLfMJId
Œ
* ‰&&
j = 1 for double parking and j = 0 for waiting or
cruising for parking
Ž
dRD&Je&ORLId&Je&DgR&HNLYYMYn&gJIM•JY
Œ
* ‹+‡]‡‘&Œ&
The following parameters are utilized to formulate long-term service costs.
P
`
* “YMD&HbIPgLdR&PJdD&eJI&fRgMPNR&DOHR&M&#cJNNLI0fRgMPNR(
P
~
`
* “YMD&IRdLNR&PJdD&eJI&fRgMPNR&DOHR&M&
cJNNLI
fRgMPNR
MY&ORLI&‘&
P
F
`
* “YMD&RYRInO&PJdD&eJI&fRgMPNR&DOHR&M&#cJNNLI0nLNNJY&JI&cJNNLI0Q=g(
I
F
`
* RYRInO&PJYdbZHDMJY&ILDR&Je&fRgMPNR&DOHR&M&#nLNNJY0ZMNR&JI&Q=g0ZMNR(
P
h
`
* “YMD&ZLMYDRYLYPR&PJdD&eJI&fRgMPNR&DOHR&M&#cJNNLI0ZMNR(
P
X
`
* –JbINO&cIMfRI&ULnR&eJI&fRgMPNR&DOHR&M&#cJNNLI0gJbI(
P
* &HLIQMYn&eMYR&#cJNNLId(
H
`s
* "IJKLKMNMDO&Je&IRPRMfMYn&L&HLIQMYn&eJI&fRgMPNR&DOHR&M&LYc&KRgLfMJbI&DOHR
P
i
`
* “YMD&LYYbLN&PJdD&eJI&fRgMPNR&DOHR&M&#cJNNLI0fRgMPNR(
e
m
* ˜MdPJbYD&eLPDJI&#™(&
e
F
* WLDR&Je&MYeNLDMJY&eJI&cMRdRN&ebRN&&#™(
c * ˜LOd&Je&dRIfMPR&HRI&ORLI
* šRLId&MY&HNLYYMYn&gJIM•JY
Z
`s
= fleet size
Z
`‡s
&
(integer) of vehicles type
M
following parking behaviour j
The sum of purchasing, resale, energy/fuel, maintenance, driver wages, parking tickets,
and vehicle fixed annual costs can be expressed as follows:
*
: :
œ
!
P
H
M
,
#
+;e
c
(
,‘
P
I
M
)
Z
;
: #
+;e
c
(
,Q
#
+;e
R
(
Q
P
R
M
I
F
`
_
Z
c
ž
&
Q*+
;
Ÿ
•*+
Š
: #
+;e
c
(
,Q
#
P
Z
M
_
Z
c
(
Q*+
;
: #
+;e
c
(
,Q
#
P
N
M
a
Z
c
(
Q*+
;
: #
+;e
c
(
,Q
#P
D
H
D
Z
c(
Q*+
;
: #
+;e
c
(
,Q
#P
L
M
Z
(
Q*+
.
Optimization Problem
The optimization problem minimizes long-term vehicle costs by selecting the best
vehicle type
M
and parking behavior j. The decision variable is the fleet size
Z
`‡s
&
(integer)
of vehicles type
M
following parking behavior j and the number of customers
Y
`s
assigned to vehicle type
M
following parking behavior j. The binary variable
O
`s
is 1
when the vehicle double parks (
ˆ * +(
and zero otherwise (
ˆ * 4(
when the driver waits
until a parking space is available.
*
Total cost over the planning horizon (dollars)
Minimize
(1)
Subject to:
Z
`s
% Y
`s
<U
m
0U
r
`
&&&&&&&&&&&&&&&&&&&&&&&„M †‡ „ˆ
(2)
a
hij
% a
`s
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&„M †‡„ˆ
(3)
H
`s
* O
`s
H
&- +&&
&„M †‡„ˆ
(4)
Y
`s
Z
`s
% 4&&&&&&&Y
`s
Z
`s
'RD&Je&†YDRnRId&&&&&&&&„M †‡ „ˆ
(5)
Z
`s
- &YO
`s
&„M †‡ ˆ * +
(6)
Z
`s
- &Y#+,O
`s
(
&„M †‡ ˆ * 4
(7)
Y -&
: :
Y
`s
¡
s87
¢
(8)
Equation (1) is the objective function, minimization of total cost. Equation (2) is a
weight/capacity constraint and equation (3) is a route duration constraint. Equation (4)
estimates the probability of receiving a fine. Equation (5) is an integer non-negativity
constraint. Equations (6) and (7) are logical constraints that link parking behaviour and
fleet size. Equation (8) ensures that all customers are served.
The reader should note that the threshold for waiting or double parking is purely
monetary. The model attempts to explain what factors may support a waiting or double-
parking strategy. It is assumed that loading zones are convenient for commercial vehicle
drivers; another dimension of the problem is the situation when commercial drivers stop
in the closest place (double-park) even when loading zones are free but not close
enough to the final delivery location (a trade-off that is not analysed in this research).
Case Study
It is hypothesized that logistics constraints and route characteristics have an impact on
parking costs, operations and behaviour. Two types of delivery services are analyzed:
less-than-truckload (LTL) and courier deliveries. LTL deliveries are heavier and require
more time per delivery than courier deliveries. LTL shipments can range between 600
and 1,200 lbs. (Morris and Kornhauser 2000) with service times ranging between 15
and 25 minutes per stop (Muñuzuri, Cortés, Guadix, and Onieva 2012). Courier services
are lighter, ranging from less than 1 to 170 lbs. (Morris and Kornhauser 2000). Courier
service time ranges from 1 to 5 minutes (Muñuzuri, Cortés, Guadix, and Onieva 2012).
Four route types are studied in this is research but due to space constraints, only one
vehicle type (a typical small delivery truck) is utilized in this research.
LTL and courier deliveries are classified into two groups: A and B; “A” types
have heavier shipment sizes, longer service times, and longer tour durations than “B”
types. The characteristics of customers LTL A, LTL B, Courier A and Courier B are
summarised in Table 1. The characteristics of the vehicle, a typical small delivery
vehicle in the USA, are shown in Table 2.
The model presented in Section 3 is utilized to minimize long-term service costs as a
function of fleet size and changing demand and supply
&#T * &/0'1(
ratios but
conditional on utilizing one strategy (waiting or double-parking). Scenarios LTL A and
LTL B are weight-constrained whereas Courier A and Courier B scenarios are time-
constrained.
Impacts of Parking Availability on Costs
Long-term costs are estimated for each scenario as a function of parking availability.
The results show that the impacts of parking availability are different for the double
parking and waiting strategies. Figure 1 shows the expected probability of no parking
and the expected waiting time as a function of parking utilization levels
&T
. The rate of
increase of the probability of no parking is steady and comparable across different
service types. However, expected waiting time varies significantly across delivery
types. For the sake of simplicity, only LTL A and Courier B graphs are shown in Figure
1; the other two scenarios (LTL B and Courier A) fall in between LTL A and Courier B
scenarios and are not included for the sake of brevity.
For LTL A routes, with longer service times, the increase of expected wait times
as a function of ρ starts to show high values – more than 5 minutes per customer – for
parking utilization values ρ > 0.60. On the other hand, for Courier B routes, the increase
of expected wait time as a function of parking utilization values starts to show high
values – more than 5 minutes per customer – for values ρ > 0.90. In the latter scenario,
the increase is very sharp when ρ > 0.90.
Costs per customer (per stop) are shown in Figure 2. For the sake of simplicity,
only the LTL A and Courier B curves are shown. In terms of absolute costs, as
expected, courier deliveries are several times more economical than LTL deliveries.
This is expected because it is more difficult to deliver heavier loads that have longer
service times; more routes, drivers, and vehicles are necessary to accommodate fewer
LTL customers per route. Courier routes are several times more efficient in terms of
utilization of resources such as vehicles and drivers.
The comparison of the costs of double parking and waiting strategies are less
straightforward. For LTL A deliveries, it is better to “wait” than to double park until ρ
£
0.90; for Courier B deliveries, it is better to “wait” than to double park until ρ
£
0.70.
The results indicate that for Courier B double parking is a nearly optimal strategy for
any ρ value, since the difference between the cost of double parking and waiting can be
barely perceived in the interval 0 < ρ
¤&
0.70. In other words, Couriers are nearly
indifferent between double parking and waiting in the interval 0 < ρ
¤&
0.70. On the
other hand, for LTL A services the difference between the cost of double parking and
waiting is noticeable in the range 0.40 < ρ
¤&
0.90.
These results indicate that the impact of parking availability on LTL and Courier
operations and behaviour are likely different. In areas with a reduced number of loading
zones and high parking demand it is expected that Courier vehicles will show a
tendency to double-park more than LTL vehicles. For LTL vehicles, waiting is a more
attractive option. LTL vehicles have longer service times and hence the probability of
parking fines are high when the vehicles are not legally parked. The parking utilization
must be high (ρ
¥&
0.90) and waiting times must be very long to outweigh the expected
parking fine costs.
Per-Stop Elasticity Analysis
Previous results are useful to highlight general trends regarding occupancy, waiting
times, cost per customer, route type, and parking demand/supply ratios. Elasticity values
are calculated in this section to get an estimate of the relative importance of service,
routing, and parking variables on long-term cost per stop or customer.
The elasticity analysis was conducted at break-even values (
¦
) of ρ where the
service cost of the double-parking behaviour equals the service cost of the waiting
behaviour. The breakeven points were chosen because at these points small changes
may result in behaviour reversals, e.g. from waiting to double parking or vice versa. The
elasticities were obtained using numerical approximations of this function:
§#›0¨‡©( *
ª#›
#
©¦
(
0¨(
ª©
&›#©‡¦(0¨
©
where:
§#›0¨‡©( *
variable
©
long-term service cost per stop elasticity
#
©¦
(
*&
per customer or stop long-term service cost
¦ *
breakeven point
Table 3 provides the elasticity values for the LTL B scenario. To facilitate a
comparison, elasticity values are sorted from highest to lowest value when j = 1
(double-park). A positive sign must be interpreted as an increase in per stop cost, for
example, if the value of the parking fine increases 1% the per stop cost is going to
increase 0.6% if the driver decides to double park and 0.0 % if the driver decides to
wait for an available parking space.
As expected, when ρ increases there is a major increase in service costs but at
the breakeven point the increase is three times higher if the driver decides to wait
instead of double park. The ratio between
§#›0¨‡T(
and
§#›0¨‡P
(
indicates that at
the breakeven point fines must increase more than 2.3 (1.37/0.6 ≈ 2.3) times faster than
the demand/supply ratio (ρ) to make double parking less appealing.
Service time has a high elasticity in the double parking scenario, almost four
times higher than in the wait scenario. This is may be explained by the fact that a
service time increase also increases the probability of receiving a parking fine while
double parking. Hence, in the double parking scenario a longer service time creates an
indirect cost increase related to parking fines and a direct cost increase related to longer
route durations. The reverse, a reduction of service time leads to a decrease in service
costs but because the decrease is much faster for companies that double park, a decrease
in service time moves the breakeven point between double-parking and waiting to the
left or a smaller demand/supply ratio (ρ). Driver hourly wage is the other variable that
has a high impact on costs, especially in the waiting time scenario.
Variables related to route length such as service area size and distance depot-
service area have a relatively small elasticity; the same can be said about the travel
speeds. Vehicle purchase cost elasticity is more important in the wait scenario but it is
five times smaller than the elasticity value for driver wages,
§#›0¨‡P
X
(
= 0.65 and
§#›0¨‡P
(
= 0.13. Other costs such as energy or the value of money (discount rate)
have low elasticity values.
Table 4 provides the elasticity values for the Courier-A scenario. Overall, the
same trends are maintained. However, a major jump is observed in the elasticity value
for ρ if the vehicle waits. At the breakeven point, for any given increase in ρ the
resulting increase in service costs per stop is 5.2 times higher if the driver decides to
wait instead of double parking.
The ratio between
§#›0¨‡T(
and
§#›0¨‡P
(
indicates that at the breakeven
point fines must increase more than 2.3 (1.17/0.5 ≈ 2.34) times faster than the
demand/supply ratio (ρ) to make double parking less appealing. The value of this ratio
is similar to the value found in the LTL scenario.
Discussion
Two key policy insights can be derived from the results: (a) double parking is unlikely
to disappear from urban areas unless more dedicated freight and service parking spaces
are available at peak times and (b) increasing parking fines and parking enforcement
can discourage double parking but it will not eradicate the problem for sufficiently high
values of demand/supply ratios (
T(
. In the long-term, urban policy may be more
productive when the focus is on requiring enough on-street and off-street parking spaces
for freight and service vehicles. These conclusions roughly agree with previous studies
(Wenneman, A., Habib, K. and Roorda, M. 2015; Chen, Q. and Conway, A. 2016).
For managers at delivery or service companies the options seem limited as well.
Large package delivery companies such as FedEx or UPS understand that parking fine
costs are just another element of the cost of doing business in congested urban areas.
Pricing policies can reflect this additional cost (as in the cited case for UPS in
Manhattan) which means that parking costs are eventually transferred to consumers in
the forms of extra costs such as service or delivery fees. Alternatively, companies can
try to lower service times or delivery costs. Some costs are not transferred to direct
consumers of freight or commercial services, for example double parking severely
restricts needed roadway capacity during peak hours which causes congestion and
emissions; congestion impacts are mainly a function of service times or double-parking
duration (Lopez et al., 2016).
For companies that double park when parking is not available the largest cost
reduction is obtained when service times are reduced. For example, delivering packages
to a package dropbox at the ground level entrance of a building can save valuable
minutes otherwise spent at the elevator or carrying a hand truck through long hallways.
For companies that usually wait or cruise until parking is available the largest cost
reduction is obtained when driver wages are reduced. Significant driver wage cuts aan
option in a competitive labour market and long-term cost reductions are usually
achieved by decreasing service times or increasing driver productivity.
Managers have an incentive to increase productivity by reducing service times,
but a reduction in service times makes (ceteris paribus) double-parking a rational
response for a wider range demand/supply ratios (ρ). On the other hand, a reduction of
driver wages makes (ceteris paribus) waiting a rational response for a wider range
demand/supply ratios (ρ). Finally, it is worth noting that increasing passenger parking
fees and assigning just a small percentage of parking to commercial vehicles produces a
significant social surplus (Amer & Chow, 2016). However, in practice it also important
to monitor that commercial vehicle zones are not taken by passenger vehicles; increased
monitoring may increase (government) costs if parking fines do not cover the cost of
enforcement.
Conclusions
This study addressed the following research questions: how does parking availability
affect distribution companies’ parking behaviour? and (ii) what are the key variables
that affect parking costs? A model where long-term service costs and fleet size are
affected by changes in parking demand/supply ratios was formulated. The model also
accounts for different parking strategies such as double-park when necessary or
wait/cruise until parking is available.
Results show that as parking availability decreases, costs increase more rapidly
for LTL services than for Courier services. The difference in cost changes is related to
customer service times and route structures. It is also observed that LTL services are
more likely to cruise or wait until parking becomes available than Courier services. LTL
vehicles have longer service times and hence the probability of parking fines are higher
if the vehicles are not legally parked. The parking utilization must be high and waiting
times long to outweigh expected parking fine costs for LTL deliveries.
The results also indicate that double parking can be a company’s rational
response, especially for Courier type services, in urban environments with high parking
demand/supply ratios. Parking policy options to tackle commercial vehicle double
parking are limited and perhaps bound to fail in the long-term unless development codes
require enough on-street and off-street parking spaces for freight and service vehicles.
A novel result is that increases in logistics or service productivity achieved through a
reduction in service times makes (ceteris paribus) double-parking a rational response for
a wider range of demand/supply ratios (ρ). This demonstrates the intricacy of the
commercial vehicle parking problem, changes at the route or customer level (that are
hard to observe for a public transportation agency) may result in undesirable (but
rational from a private company perspective) changes in commercial vehicle parking
behaviour.
References
Amer, A., & Chow, J. Y. (2016). A downtown on-street parking model with urban truck
delivery behavior. Transportation Research Part A: Policy and Practice.
Aiura, N. and Taniguchi, E. (2006) Planning On-Street Loading-Unloading Spaces
Considering the Behaviour of Pickup-Delivery Vehicles and Parking Enforcement.
Recent Advances in City Logistics, the 4th International Conference on City
Logistics, pp. 107-119. Langkawi (Malaysia): Elsevier.
Berezin, L. (2014) Double Parking Ticket Blitz will cost you a $115 Parking Fine, in: the
New York Parking Ticket: http://newyorkparkingticket.com/double-parking-ticket-
blitz-will-cost-115-parking-fine/ (accessed 30.08.15)
Chen, Q., & Conway, A. (2016). Commercial Vehicle Parking Availability and Behavior
for Residential Delivery in New York City. In Transportation Research Board 95th
Annual Meeting (No. 16-4597).
City of New York. (2013) Trucks & Commercial Vehicles.
http://www.nyc.gov/html/dot/html/motorist/trucks.shtml (accessed 22.10.16)
Daganzo, C. F. (2005) Logistics Systems Analysis. Springer.
Durand, B., & Gonzalez-Feliu, J. (2012, January). Impacts of proximity deliveries on e-
grocery trips. In Supply Chain Forum: An International Journal (Vol. 13, No. 1, pp.
10-19). Taylor & Francis.
Figliozzi, M. A. (2007). Analysis of the efficiency of urban commercial vehicle tours:
Data collection, methodology, and policy implications. Transportation Research Part
B: Methodological, 41(9), 1014-1032.
Figliozzi, M. A. (2008) Planning Approximations to the Average Length of Vehicle
Routing Problems with Varying Customer Demands and Routing Constraints, in: the
Transportation Research Record: Journal of the Transportation Research Board, 2089,
pp. 1-8.
Figliozzi, M. A. (2010) The impacts of congestion on commercial vehicle tour
characteristics and costs, in: the Transportation Research Part E: Logistics and
Transportation Review, 46, pp. 496-506.
Figliozzi, M & Tipagornwong, C. (2016, June). The Impact of Last Mile Parking
Availability on Commercial Vehicle Costs in Congested Urban Areas, In Information
Systems Logistics and Supply Chain: ILS Conference 2016: Building a Resilient
Future.
Fischer, M. J., & Han, M. (2001) NCHRP Synthesis 298: Truck Trip Generation Data: A
Synthesis of Highway Practice. Washington D.C.: Transportation Research Board.
Gordon, R. (2007) Parking tickets by the truckload / 18 S.F. businesses rack up
thousands of citations, pay city on monthly plan, in: SF GATE:
http://www.sfgate.com/news/article/Parking-tickets-by-the-truckload-18-S-F-
2615428.php (accessed 30.08.2016)
Halsey, A. (2013) In D.C., parking tickets are a cost of doing business, in: the
Washington Post: https://www.washingtonpost.com/local/trafficandcommuting/in-
dc-parking-tickets-are-a-cost-of-doing-business/2013/06/01/6c693a56-b357-11e2-
9a98-4be1688d7d84_story.html (accessed 30.08.2016)
Hawkins, A. J. (2013) Parking tickets: All in the cost of doing business, in: Crain's New
York Business
http://www.crainsnewyork.com/article/20130526/ECONOMY/305269980/parking-
tickets-all-in-the-cost-of-doing-business (accessed 30.08.2016)
Jaller, M., Holguín-Veras, J., & Hodge, S. (2013). Parking in the city: Challenges for
freight traffic. Transportation Research Record: Journal of the Transportation
Research Board, (2379), 46-56.
NBC News. (2006) Delivery firms’ big ticket item: Parking fines, in: NBC News.com:
http://www.nbcnews.com/id/14602712/ns/business-us_business/t/delivery-firms-
big-ticket-item-parking-fines/#.Vg8M7_lVhBd (accessed 30.08.16)
Langevin, A., Mbaraga, P., and Cambell, J. F. (1996) Continuous approximation models
in freight distribution: An overview, in: the Transportation Research Part B:
Methodological, 30, pp.163-188.
Lopez, C., Gonzalez-Feliu, J., Chiabaut, N., & Leclercq, L. (2016, June). Assessing the
impacts of goods deliveries' double line parking on the overall traffic under realistic
conditions. In Information Systems Logistics and Supply Chain: ILS Conference
2016: Building a Resilient Future.
Marcucci, E., Gatta, V., & Scaccia, L. (2015). Urban freight, parking and pricing policies:
An evaluation from a transport providers’ perspective. Transportation Research Part
A: Policy and Practice, 74, 239-249.
Millard-Ball, A., Weinberger, R. R., and Hampshire, R. C. (2014) Is the curb 80% full or
20% empty? Assessing the impacts of San Francisco’s parking pricing experiment,
in: the Transportation Research Part A, 63, pp. 76-92.
Morris, A. G., and Kornhauser, A. L. (2000) Relationship of Freight Facilities in Central
Business District Office Buildings to Truck Traffic, in the Transportation Research
Record: Journal of the Transportation Research Board, 1707, pp. 56-63.
Morris, A. G., Kornhauser, A. L., & Kay, M. J. (1999) Getting the Goods Delivered in
Dense Urban Areas: A Snapshot of Last Link of the Supply Chain, in: the
Transportation Research Record: Journal of the Transportation Research Board, 1653,
pp. 34-41.
Muñuzuri, J., Cortés, P., Guadix, J., and Onieva, L. (2012) City logistics in Spain: Why
it might never work, in: Cities, 29, 133-141.
Pluvinet, P., Gonzalez-Feliu, J., Faivre d’Arcier, B., Gardrat, M., Basck, P., Ambrosini,
C., & Routhier, J.L. (2012). Methodology, evaluation, simulation and assessment for
the analysis of the deployment of DSB and EEIC systems of the FREILOT project.
Contribution of LET. Research report, Laboratoire d’Economie des Transports, Lyon.
Wenneman, A., Habib, K. & Roorda, M. (2015). Disaggregate analysis of relationships
between commercial vehicle parking citations, parking supply, and parking
demand. Transportation Research Record: Journal of the Transportation Research
Board, (2478), 28-34.
United Parcel Service of America. (2015) 2015 UPS Rate and Service Guide: Retail
Rates. http://www.ups.com/media/en/retail_rates.pdf (accessed 13.07.15)
ACKNOWLEDEGEMENTS
Financial support for this research was provided by the Freight Mobility Research
Institute (Transportation Center) and the Transportation Technology and People lab at
Portland State University. Any omissions or mistakes are the sole responsibility of the
authors.
Table 1. Route and Service Characteristics
Parameter
Scenario
LTL A
LTL B
Courier A
Courier B
Number of daily stops
400
400
400
400
Service area size (sq. mile.)
8.5
8.5
8.5
8.5
Distance between a depot and a service
area (miles)
4.5
4.5
4.5
4.5
Customer demand (lb./stop)
450
80
10
10
Service time (minutes)
20
6
3
3
Time window (hours)
8
6
4
2
Planning horizon (years)
5
5
5
5
Average speed (mph)
- Inside service area
- Outside service area
10
30
10
30
10
30
10
30
Delivery days per year
260
260
260
260
Discount factor
6.5%
6.5%
6.5%
6.5%
Fuel/energy inflation
2.5%
2.5%
2.5%
2.5%
Table 2. Characteristics of a Single Unit Truck
Parameter
Truck
Make
Isuzu N-series
Fuel tank / battery size
25 gallon
Fuel / electricity consumption rate
10 mpg
Gross vehicle weight
12,000 lbs.
Tare
5,672 lbs.
Payload
6,328 lbs.
Lifetime
12 years
Purchase cost
$ 50,000
Maintenance cost
$ 0.20 / mile
Vehicle insurance
$ 2,336 /year
Vehicle registration
$ 391 /year
Diesel / electricity cost
$ 2.689 / gal
Driver wage
$ 16.28 / hour
Driver health insurance
$ 7,000 / year
Driver Social Security/Medicare taxes
7.65% of driver compensation
Driver pension/retirement
25% of driver compensation
Table 3. Elasticity Values for the LTL-B Scenario
Variable
j = 1
(double-park)
j = 0
(wait)
Demand/supply ratio (ρ)
1.37
3.85
Service time, D
E
0.80
0.21
Parking fine, P
0.60
0.00
Driver wage
P
N
0.25
0.65
Purchase cost, P
0.06
0.13
Discount factor, e
m
0.02
0.04
Service Area (SA) Size, A
0.02
0.03
Distance depot to SA, r
0.02
0.05
Energy cost, P
F
0.01
0.02
Speed outside SA, «
i
-0.02
-0.03
Speed inside SA, «
p
-0.04
-0.04
Table 4. Elasticity Values for the Courier-A Scenario
Variable
j = 1
(double-park)
Demand/supply ratio (ρ)
1.17
Service time, D
E
0.68
Parking fine, P
0.50
Driver wageP
N
0.27
Purchase cost,
P
0.08
Discount factor, e
m
0.04
Service Area (SA) Size, A
0.03
Distance depot to SA, r
0.03
Energy cost, P
F
0.02
Speed outside SA, «
i
-0.02
Speed inside SA, «
p
-0.07
Figure 1. Occupancy and Average Waiting Time vs. parking utilization (ρ)
LTL A (service time = 20 min)
Courier B (service time = 3 min)
Figure 2. Long-term per-stop costs vs. parking utilization (ρ)
LTL A
Courier B
0
10
20
30
40
50
60
0.00
0.20
0.40
0.60
0.80
1.00
0.00 0.50 1.00
Av. Wait time (min)
Prob. of FLZs occupied
Parking Utilization Factor (ρ)
Probability of All FLZs occupied
Expected waiting time (minute)
0
10
20
30
40
50
60
0.00
0.20
0.40
0.60
0.80
1.00
0.00 0.50 1.00
Av. Wait time (minute)
Prob. of FLZs occupied
Parking Utilization Factor (ρ)
Probability of All FLZs occupied
Expected waiting time (minute)
0
10
20
30
40
50
0 0.2 0.4 0.6 0.8 1
Per-stop cost (dollar)
Parking utilization factor (ρ)
Double parking Waiting
0
10
20
30
40
50
0 0.2 0.4 0.6 0.8 1
Per-stop cost (dollar)
Parking utilization factor (ρ)
Double parking Waiting