Concerns have been expressed about proposals to use the hard shoulders on the M1 motorway to ease congestion.
A report has suggested the hard shoulders from Belfast to Blaris could be used when traffic is at its worst.
However, Lisburn Councillor Alexander Redpath said he had concerns about safety aspects of the proposals.
Consultants estimate the project could cost between £60 and £70 million if adopted.
Transport NI asked experts to examine creating additional capacity on motorways due to “recurrent traffic congestion at peak times”.
Their report suggested the M1 and M2 in and out of Belfast become so-called “smart motorways”, similar to those operated in England.
The hard shoulder on each side of the M1 between Stockman’s Lane and Blaris would be turned into traffic lanes.
The proposal is still in the early concept stages but is said to be “value for money”.
A summary of the report submitted to Transport NI highlighted that one drawback could be that it may encourage car use at the expense of public transport.
The Freight Transport Association, which represents haulage firms, said the idea should be “given serious consideration.”
Responding to the proposals, Councillor Alexander Redpath said: “I have read with interest reports by consultants that hard shoulders on the M1 should be turned into traffic lanes during peak times.
“I will keep an open mind about these proposals but there are obvious concerns about safety which will need to be answered. We have had a number of serious accidents in recent months on our motorways and dual carriageways.
“I would need assurances that using hard shoulders as traffic lanes wouldn’t impede the emergency services should they need to access a crash site to save and protect lives.
“We must also remember that there is no quick fix to the congestion affect the M1, especially at the junction with the A1 at Sprucefield. Excellent progress was made by my colleague Danny Kennedy to progress the Blaris by-pass.
“I will be pressing his successor to deliver the necessary funds to deliver this scheme which I believe will alleviate traffic problems in and around Sprucefield and Hillsborough.”