SERVER BiRKAN

AYTEKiN ÇiLLi, EGO Transportation Planning Division

A.FUAT ÇETİN, AHMET TÜMAY, ERTÜRK ÇELENK AKBİS Project Group

ANKARA City Traffic Impact Assesment Study

ABSTRACT:

Increasing demand on transportation network results with high noise and exhaustive emission pollution without any planning and regulations.Estimating and taking precautions for five years later network is important as much as for network at the time being. It is a great advantage to observe the actual case and forecasted case, comment between them over an original digital terrain model. Documentation of the network and taking reports by considering important criteria is another part of the job. So let's imagine such a kind of network managing, viewing, analyzing tool which relates graphical and tabular data for our and city own benefit. That's why we need to improve this model!

INTRODUCTION:

• preparing a city traffic arteries database ·
• what will be the Ankara-2005 network graphically and parametrically ·
• to observe the physical location of traffic network on 3D terrain model ·
• to obtain approximate exhausts and noise amount due to the traffic flow

DATABASE PREPARATION:

Firstly, 1/20000 scale maps were scanned and transformed the digital raster format and stored workstation. These raster data were used for digitizing urban transportation network of Ankara. It was transformed to real world coordinates, registered and rectified.

On the other side proper parameters and data were prepared for transportation simulation program TRANPLAN. Next, computed and simulated data (traffic flow in passenger car unit) stored in ASCII format . This part of the project was done in coordination with Transportation Planning & Rail Transit Systems Division of Great City Municipality. Arc-node data model was used. By using same node numbers in Tranplan model and ArcInfo coverage a relation was built. Then by developing a data filtering process, output data format of TRANPLAN was filtered into ArcInfo Info format and linked. Other kinds of data like physical data i.e. number of lanes, lane width, lane type and capacity were entered manually by operators. Inf. database contains totally 35 data columns.

ENVIRONMENTAL TRAFFIC IMPACT DATABASE:

Two major aspects of traffic impacts are exhaustive emission and noise pollution. These two aspect must be analyzed and controlled for public health.

exhaustive emission pollution:

When considering transportation modes of City it is evident that most exhausted emission is COx. So exhaustive emission term refers COx in this paper. Two different exhaustive emission factors for carbonmonoxides were calculated. One of them was calculated according to Federal Test Procedure FTP , and the other of them was based on a statistical research which was carried out for Ankara City traffic network.

Using FTP Method:

The calculation of composite exhaust emission factors using the FTP method is given by:

enpstw = S cipn min vips zipt riptw

enpstw = Composite emission factor in g/km for calendar year (n), pollutant (p), average speed (s), ambient temperature (t),and percentage cold operation (w)

cipn = The FTP mean emission factor for the ith model year light-duty vehicles during calendar year(n) and pollutant (p)

min = The fraction of annual travel by the ith model year light-duty vehicles during calendar year (n)

vips = The speed correction factor for the ith model year light-duty vehicles for pollutant (p) and average speed (s)

zipt = The temperature correction factor for the ith model year light-duty vehicles for pollutant (p) and ambient temperature (t)

riptw = The hot/cold vehicle operation correction factor for the ith model year light-duty vehicles for pollutant (p) and ambient temperature (t) and percentage cold operation (w)

As a result an approximate COX factor, 53.9 gr/(km*vehicle) was obtained.

to convert it into a density of 10-3 gr/m3 unit and evaluate, a road with 30m width between left part of it with 5 story building in a row and right part 5 story building in a row and a closed weather block was assumed (one story height is approximately 3m) volume of a segment, x meter : 50m*(5*3m height)* x = 750x m3

So the expression as below gives us exhaustive emission density as gr/(m3*hr)
(53.9*10-3gr/km*vehicle)*(x km)*(# of vehicles per hour)/ 750xm3

eg. for a road segment passed weather block with 6000 vehicles/hour: 53.9*10-3 * x * 6000 /750x = 431.2 mg/(m3*hr) COX

• 1995 actual case

• 2005-without rail transit system

• 2005-with rail transit system

Statistical Method:

NOISE POLLUTION:

Leq = 10 log(Q) +20 log(V) - 10 log (d+w/3) + Kc + 14

Q = traffic flow
V = speed
d = distance from road edge
w = road width
Kc = correction factor (depends on pavement type) = 4

acoustic pressure level decreases as going far away from road edge. SES item was computed at middle way of roads. There are some important acoustic pressure limits determined to prevent healthy hazards 2. The road segments where the amount of acoustic pressure level exceeds the limit where physical damages begin at the middle of the street segment were listed and marked . The buffer distances where the acoustic pressure level at the middle of the street segment drops to determined limits ( 70dB, 60dB, 55dB) were calculated as below.

Leq = 10 log (Q) +20 log (V) - 10 log (d+w/3) + Kc + 14...................(eq 1)

Kc +14 = 18 so,

L = 10 log (Q) + 20 log (V) - 10 log (d) + 18
(L-18) = log Q10 + log V20 - log d10
10(L-18) = Q10 *V20 / d10
d10 = 10(18-L) * Q10 *V20
d = Q * V2 * 10 (18-L)/10....................................................................................(eq 2)

According to these distances buffer zones were created. Central part of the city plan was overlaid on these buffer zones and most polluted part of the city was analyzed (these three critical buffer zones are BUFFER70, BUFFER 60 and BUFFER55 in database)

eg. for a road segment which has volume = 5000 vehicle/hour & average speed = 15 km/hr max. acoustic pressure level is 78.511 dB (from eq 1) the distance where pressure level drops at 70 dB is 7,1 m (from eq.2) the distance where pressure level drops at 60 dB is 71 m the distance where pressure level drops at 55 dB is 224,5 m

• · 3D model of Ankara was obtained from digital 50m lattice by the help of TIN

• road network segments were colored or were been bold according to their flow, emission and acoustic pressure level

whole ANKARA Network

central ANKARA

• these road coverages were overlaid on the 3D terrain model

• 3D terrain model are colored using GRID module

• ArcView is installed as querying and analyzing tabular database

• -show me " Atatürk Bulvarı"

• - show me "the street segments which has 3 lanes"

• - show me "the street segments where traffic flow is between 2000-4000 vph"

• - show me "the street segments where forecasted flow in 2005 exceeds capacity"

• - show me "the street segments where acoustic pressure level is 80 dB or between 65-73 dB etc."

• - show me "the first 10 street segments where emission level is maximum"

• - show me " the street segments where acoustic pressure level is between 70-80 dB and volume is between 5000-6000 vph and emission level is greater than 500mgr/m3"

CONCLUSION

REFERENCES:

- VDI 2058, Part 3, 1981

- " Noise pollution" Edited by A. Lara Saenz, RWB Stephens Part 3 chapter12

- Automobile Exhaust Emission Surveillance prepared for EPA March 1973