The newts have suffered from a loss of pond habitats
Newts which caused a three-month delay and extra costs of £1m to a bypass in Leicestershire have failed to appear.
It had been thought a colony of the protected great crested newt was threatened by construction of the road around Earl Shilton.
Under European law, the county council had to install protection fences and traps, halting the project.
But after a month of searching not a single newt has been found, prompting officials to question the move.
It is against the law to injure, capture or disturb the amphibians in any way without a licence.
The creatures live on land but return to ponds to breed in the spring.
The county council's engineering manager Derek Needham said regular checks were made.
"Within the site, in case any newts are trapped, we have put down traps every 20m which have to be inspected twice a day once it gets above 5C.
"Over the past 30 days we have caught a number of normal newts but no great crested newts."
Council leader David Parsons said: "I don't think it is a waste of time but I think it is a question of balance.
"I think we have to talk to government about the balance between money and saving wildlife, because I don't think we have got it right."
Natural England, the body charged with monitoring the newts, said the creatures had the same level of protection across the EU.