Geoscience Reference
In-Depth Information
increases on VKT, number of trips, and travel time in each and every one of the
super zones and in all of them together. A comparison was made with respect to the
base-case scenario.
21.3.4 Pollutant-Emission Model
The basic emission model includes the product of two variables: the emission factor
of the pollutant and the level of activity that a certain type of vehicle produces. The
pollutant emissions from motor vehicles depend on both variables, and the emission
factor depends on vehicle speed (Parra et al.
2006
).
The following emission model is based on the variables mentioned above;
however, the calculation is done on the basis of emission per road link, per hour,
in our case the morning peak hour. This allows us to calculate pollutant emissions at
the level of traffic analysis zones or super zones, thereby creating better conditions
for analyzing differences in the level of pollutant emissions among the various
zones within the TAMA.
Equation (
21.2
) is slightly modified from Parra et al. (
2006
) in order to enable
the calculation of average pollutant emissions per link per hour:
n
X
E
i
,
l
¼
V
j
,
l
L
l
F
i
,
j
SðÞ
ð
21
2
Þ
:
j¼
1
Where:
E
i,l
—Hot exhaust emissions (expressed in g h
1
) of pollutant
i
in link
l
per hour
(morning peak hour in our case)
V
j,l
—Hourly volume of vehicle flow of category j for link l (in our case, only
three categories were considered: private vehicles, buses, and trucks)
L
l
—Length of link
l
F
i,j
—Hot exhaust-emission factor for pollutant
i
of vehicle category j
S
l
—Average speed on link
l
N
—Number of categories
21.4
Results
21.4.1 Reducing Parking Supply
As presented in the methodology section, the first test dealt with the effect of
reducing the parking supply in the Tel Aviv CBD. This paper assumed a parking-
supply reduction of 20 %, which consequently led to a reduction of 20 % in private
vehicle trips entering the CBD during the morning peak hours. The assumption is
consistent with results from the 1996/1997 NTHS survey, which showed that most
employees arriving at the CBD during the morning peak hour found a parking space
