That's one finding in an appraisal of the Retire Your Ride program, which ended in March.
An evaluation completed in February suggests there were plenty of potholes in the program's early days.
The Conservatives announced the so-called scrappage program in 2008. It offered Canadians incentives, such as public transit passes and small amounts of cash, to junk older vehicles.
Environment Canada hired Ottawa consulting firm Goss Gilroy to evaluate the program shortly before it ended. The Canadian Press obtained the report under the Access to Information Act.
The document says the government's goal of getting 200,000 old cars and trucks off the road was "too ambitious." The feds ultimately fell short of their goal, bringing in around 130,000 vehicles.
That's partly because it took longer than expected to get the program up and running. It was finally launched in January 2009.
"Target did not consider 18 months preparation time to implement the program," the report says. "Unrealistic objectives were recognized upfront."
The not-for-profit organization Summerhill Impact, formerly known as the Clean Air Foundation, handled the national management of the program. Regional, non-governmental partners across the country delivered the program in cities and town.
The consultant's report found problems with that approach.
"Challenge for (Summerhill Impact) in ramping up and in developing a regional NGO network. Very time consuming," the document says.
"NGOs and (Summerhill Impact) lacked capacity for financial management of this scale."
There was also confusion over who reported to whom.
"Roles and responsibilities unclear upfront in areas of communications, reporting. Line of authorities unclear from the perspective of regional NGOs," the report says.
"Unclear understanding of program objectives among regional NGOs."
The document does note most of these issues were resolved after the first year.
Still, the evaluation found Summerhill Impact and the local groups didn't quite realize how much work they had in store.
"SI and some NGOs had underestimated the amount of work required to deliver the program," the report says. "(Environment Canada) intervened to ensure that SI had enough (human resources) resources."
A planned advertising blitz was also scrapped. Environment Canada says that's because they thought it was better for Summerhill Impact and the local groups to do their own advertising.
"The government of Canada did not run a mass media campaign as it was felt it was more appropriate for the national not-for-profit organization and local not-for-profit delivery organizations responsible for delivering Retire your Ride to manage all program promotion," spokesman Mark Johnson said in an email.
The government says the program reduced smog-forming emissions by 4,700 tonnes. There are no plans to re-start the program.