Project Benefits

When a countermeasure or a set of countermeasures are planned to be implemented the total benefits that include the present value or any obligation (also which includes in the future) would fall under the total benefits — that is, considers the crash reduction factors, current AADT, etc.

The Equivalent Uniform Annual Benefit (EUAB) is computed based on the following information

• Time period of analysis.
• Expected growth rate of annual average daily traffic (AADT).
• Expected reduction in crashes.

The following assumptions are considered

• Expected growth rate of annual average daily traffic (AADT) is constant for the various treatments and across the whole analysis period.
• Time period of analysis is constant for the various treatments.

 The following equations are used to calculate the EUAB:

Equivalent Uniform Annual Benefit (EUAB) = B/n

B = AADT_adj*CRF*∑(CC_a*CF_a)

where

AADT_adj = (1+AADT_g)ⁿ

AADT_g=AADT Yearly growth rate factor (%)

AADT_adj =AADT Adjustment Factor

n = Analysis period in years

CRF = Crash reduction factor (%) 

a = severity level (K, A, B, C, and O)

CF_a  = Crash frequency of a particular type of crash (K, A, B, C, and O)

CC_a = Crash costs for a particular type of crash severity (from Crash Costs table)

Project Costs

When a countermeasure or a set of countermeasures are planned to be implemented the total costs that include the present value or any obligation (also which includes in the future) would fall under the total costs — that is, the present value of implementation (construction, operating and maintenance costs) over the service life of the project are included in the assessment of expected project costs.

The following equations are used to achieve the EUAC

Equivalent Uniform Annual Costs (EUAC) = (∑Costs*CR) -SV*SF - AMC

SV = Salvage Value = Salvage Value or ∑Costs*(Salvage Percentage)

∑Costs = Project Cost + Countermeasure Cost

AMC = Annual Maintenance Cost

CR= Capital Recovery =i*(1+i)^l/(1+i)^l -1)

SF = Sinking fund = i/(1+i)^l -1)

i = interest rate (assumed interest rate /100)

l = Service life

Benefit/Cost (B/C) Ratio

A benefit cost-ratio is the ratio of the EUAB and EUAC for the project. When BCR are greater than 1 then the projects are economically justified.

B/C = EUAB/EUAC