Question 1
As part of a major corridor expansion project, it is proposed to upgrade an existing single-carriage way to a
dual-carriage way and to improve some of the junctions. The time frame for the construction for
...
Question 1
As part of a major corridor expansion project, it is proposed to upgrade an existing single-carriage way to a
dual-carriage way and to improve some of the junctions. The time frame for the construction for the scheme is
set at 2 years, with the benefits of the scheme accruing to the road users at the start of the third year. Three
main benefits are taken as time savings, accident cost savings, and VOC reductions. Construction costs are
incurred mainly during the two years of construction, but the ongoing annual maintenance costs must be
allowed for throughout the economic life of the project, taken in this case to be 10 years after the road has
been commissioned.
The following basic data has been obtained and assessed for this analysis:
Parameter Detailed description
Accident rates 0.85 per million vehicle-kilometers (existing road)
0.25 per million vehicle-kilometers (upgraded road)
Average accident cost £10,000
Average vehicle time savings £2.00 per hour
Average vehicle speeds 40km/h (existing road)
85km/h (upgraded road)
Average VOC {
2+
35
v
+0.00005 v
2
100 }£ per km
; where v = average vehicle speed
Discount rate 6%
The traffic flows and the construction and maintenance costs/operating costs for the highway proposal are a
in the table below:
Question 2
A w% increase in downtown parking costs resulted in an f% reduction on downtown auto trips and a
g% increase in transit patronage for downtown routes. Derive the expressions for the arc elasticity of
auto and transit demand with respect to parking costs.
Solution
Let p1 and p2 represent the initial and new parking fee, respectively. A1 is the auto travel demand
before the parking fee increase, A2 the auto travel demand after the parking fee increase, T1 the
transit travel demand before the parking fee increase, and T2 the transit travel demand after the
parking fee increase. The percent change in auto use with respect to an increase in parking costs is a
direct elasticity, while the percent change in transit use with respect to an increase in parking
costs is a cross elasticity:
That is;
Initial parking price = p1
Final parking price = p2 = (1 + w
100
¿ p1
Initial transit demand = VT1,
Final transit demand = VT2 = (1 + g
100
¿ VT1
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