Effect of fuel price on projectunit cost 1

[BZG]

Hello
Am designing a trunk road 140km, the donor wants me to calculate/present effect of rise/fall (+/- 20%)of fuel price on project unit cost. Does any one have Idea on how to do it.
Thanks
GZE

 

[bimr]

Here is a method from the FHWA:

http://www.fhwa.dot.gov/programadmin/contracts/ta50803.cfm