1 What evidence exists in this case of potential supplier collusion?
The evidence that exists in the case of potential supplier collusion is that each chose to bit only on certain types of aggregates, which is very suspicious and raises further concern.
2 How does a purchaser know he or she is getting a fair price in a bid situation?
Awareness of the many cost components that lead to a target cost and market price is an essential requirement for the procurer who wishes to assess whether the person is getting good value
3 Why would suppliers voluntarily lower prices on a fixed price contract?
This again shows signs of collusion, but in this case we can also read that since there were a slump in the local construction industry, they lowered their prices to keep business and renew contract with their current buyer.
4 Is it reasonable to adjust price based on a general inflation index?
I think is reasonable to create a contract where the supplier adjusts their price based on a general inflation index. I think if helps the supplier to generate revenue, generate work and keep a fair price for the buyer where the inflation rate keeps rising.
5 How should the performance of a public buying office be measured?
Cost saving generated