Reliability of data sources on road conditions, traffic counts, and traffic growth used during Compact Development. One of the most sticking points throughout this evaluation, was the issue over data quality to inform the Cost Benefit Analysis and Economic Rates of Return, including divergences in the baseline traffic count for the RN6.
MCC has been addressing this lesson by registering it in the officially published Principles into Practice under Lesson #6: need to standardize quality and content of road data collection across the project.