Campaigners in favour of congestion charging in Edinburgh have said it would be "astonishing" if the referendum produces a yes vote.
The media is said to have distorted the "yes" campaign
David Spaven, of TRANSform Scotland, said there had been a campaign of misrepresentation of the true facts.
About 300,000 residents were asked if they were in favour of cordons, similar to those in London and what is under consideration in Bristol.
Opponents are optimistic that the result, due at 1130 GMT, will be "no".
If approved, motorists would be charged £2 a day with fines of £60 for those who did not pay up.
The cordons would operate from Monday to Friday with an outer one for the morning rush hour and an inner one in operation until 1830 at night.
Polls officially closed in Edinburgh at 2100 GMT on Monday following a two-week postal ballot.
Before the polls closed officials suggested there had been a relatively high 60% turnout following a late surge in voters since the weekend.
The "yes" lobby claims congestion charging will mean less traffic, cleaner air and public transport improvements.
"No" campaigners argue it will damage the economy and push traffic into residential areas of the city.
Mr Spaven believes the pro-charge campaign has been hampered by a lack of resources and an unfavourable press.
He refused to predict the result but said: "I think it would be astonishing if we do get a yes vote, because there has been such a campaign of misrepresentation in Edinburgh because people haven't had the facts about congestion charging put before them.
"We have done the best we can, we haven't got the local newspapers on our side, we don't have the resources and that has made it difficult. But let's wait and see."
A scene of congestion in the centre of Edinburgh
He admitted that if people had voted no, the congestion charging issue would be off the political agenda for the next few years.
Lorna Hudson, from Edinburgh Communities Against Congestion Charging, said residents were specifically against the two cordon system being proposed.
"It's projected that there will be rat running around these cordons because people will want to dodge the £2 fare. That particular increase is near schools and residential areas," she said.
She understood that £1.1bn would be spent over the next five years and that would go "a long way to getting better buses and rail in place before we have to pay a £2 charge".
'Carrot and stick'
Edinburgh City Council said net revenue from the proposed charge was forecast to be £761m over 20 years and the money would be used to fund transport improvements.
Mr Spaven said the issue was not totally about revenue.
He explained: "It is not good enough to throw money at public transport, you also have to have traffic restraint, you have to have carrot and stick.
The charging plan has ended up before a judge in Edinburgh
"If we don't have congestion charging, where is the stick coming from? We will end up being also-rans in European transport policy instead of being at the cutting edge of European transport policy."
Transport Secretary and Edinburgh Central MP Alistair Darling said he supported the move and would accept the judgement of the people in Edinburgh.
Mr Darling, who is also Scottish Secretary, said the UK Government had declared its interest in road pricing schemes because of congestion problems "not just in Edinburgh but in every other British city".
Fife, Midlothian and West Lothian councils have mounted a legal challenge to the plans.
The three authorities have asked the Court of Session for an exemption for residents in outlying areas as they claim motorists living just as close to the city in neighbouring councils will be hit by the charge.
INNER CORDON ENTRY POINTS
1a. Glenogle Road
2. Brandon Terrace
4. Eyre Place
5. Cornwallis Place
6. Mansfield Place
7. East London Street
8. Leith Walk
10a. Regent Terrace
11. Regent Road
12. Calton Road
14. Holyrood Road
15. St Leonard's Street
16. Clerk Street
17. Hope Park Crescent
18. Melville Drive
21. Home Street
22. Dundee Street
23a. West Approach Road (Dundee Street access)
23b. West Approach Road (Westfield Road access)
24. Dalry Road
25. Roseburn Terrace
26. Belford Road
28a. Randolph Cliff
30. Deanhaugh Street
OUTER CORDON ENTRY POINTS
1. A199 Edinburgh Road
2. A1 Musselburgh By-pass
3. A6095 Newcraighall Road
4. Whitehill Road
5. A6106 The Wisp
6. A7 Old Dalkeith Road
7. A772 Drum Street
8. Lasswade Road
9a. A701 Burdiehouse Road
9b. Southhouse Broadway
10. A702 Biggar Road
11. Dreghorn Link
12. A70 Lanark Road
13. Baberton Junction
14. A71 Calder Road
14a. Edinburgh Park South Access
15. South Gyle Broadway
16. A8 Glasgow Road
17. A90n Queensferry Road