Sir David hopes to find new ways to cut congestion
Small businesses are being asked to outline the impact that congestion on the A12 in Essex has on their firms.
The county council is holding the first inquiry of its kind by a local authority into a major trunk route.
It estimates traffic problems and delays on the A12 cost the county's economy about £250m a year.
Every local member of the Federation of Small Businesses is being asked to reply to six questions relating to their experiences of the road.
The questions include how often they use the road, whether a supplier has experienced delays due to A12 congestion, whether a customer has experienced delays in reaching the firm due congestion and what improvements they would like to see.
The A12 is owned and operated by the Highways Agency and runs for 121 miles (195km) between London and Great Yarmouth in Norfolk through Essex and Suffolk.
The inquiry is being led by Sir David Rowlands, a former Permanent Secretary at the Department for Transport.
Transport Spokesman for the local FSB, Ian Cass, said: "We are asking firms to complete the survey and return it to us before 7 May so that we have time to analyse the data and then submit the evidence to the inquiry.
"It is not just our own members we want to hear from as we know there are some 70,000 businesses based in Essex.
"We believe the A12 will have an impact on them too which is why we have an online version of the survey that any business in the county can complete."