D. CHIMBA ET AL. 303

Traffic Assignment

From O-D Survey From SUE Deviation (%)

Route A 24,600 28,000 13.8%

PR-153 15,400 12,000 22%

6. Conclusions

Thaper integrated the findings from origin-destination

(O-Dey and ststic userium in

routeation ste news propo the

townamo, Pu. Thsed nete is

ex

e town were deter-

minedm the O-D surv assignments

on thnew atesed-

ings from O-D survey.

ic Userium was th

to ork uitial volumes assigned

from O-D survey findings. Included in the SUE was tra-

s which is controlled by the free flow

ty, length of the link and si

assignment on new route was i

cr

[1]

ure Travelers to the United States by Income Level,” Jour-

e p

) survochar equilibapproach

reloc

of Co

udy. Th

erto Rico

route i

e propo

sed in

w rou

pected to capture diverted traffic currently using exist-

ing routes. The O-D provided the existing traffic pattern

and characteristics with respect to trip purposes, and the

percentages for internal and external trips. Percentages of

trips from major cities surrounding th

fro

e

ey. The initial trip

nd existing rous were ba on the find

Stochastr Equilib(SUE) en applied

the netwsing the intraffic

vel time on the link

speed, maximum capacignal

spacing density. Apart from link travel time, the utility

function of SUE contained other link measures of effec-

tiveness such as time spent in the vehicle (in-vehicle time

coefficient), congestion index and cost due to gasoline

consumption (cost coefficient). The gasoline cost consi-

dered vehicle fuel efficient of 20 miles/gallon, gasoline

price of $4.15/gallon and length of the link. All these link

characteristics were used to optimize the traveler choice

of the route.

Traffic assignment from the SUE was slightly different

from those initially assigned using O-D, indicating there

was optimization. The n-

eased by 13.8% from the one assigned using O-D while

assignment on the existing link was reduced by 22%. The

final optimized volumes were within capacity limits for

each link indicating successful optimization. The final

traffic assignment from SUE was used in the new route

design. The findings from this study showed the possible

benefit of integrating O-D with other trip assignment opti-

mization approaches. By integrating O-D survey with opti-

mization algorithms like UE or SUE can result in a well

balanced links which take into account all possible con-

strains.

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