Campaigners are lobbying Downing Street after a change in the way cars can drive through the Blackwall Tunnel.
The rush-hour tidal flow was shut in April because of dangerous driving
Conservative London Assembly members Bob Neill and Roger Evans have signed a petition which has been posted on the Downing Street website.
Previously one of the southbound lanes was given to northbound traffic during morning rush hour to ease congestion.
But Transport for London has stopped that system through the tunnel in south east London because of bad driving.
Mr Evans, the Conservative's Transport Spokesman on the London Assembly said: "The next step is to see how many signatures the petition can gain and I would urge everyone in south-east London to take the time to log on and sign it."
He criticised the decision to close the tunnel on the grounds that it led to dangerous driving by insisting more should be done to prosecute those motorists who are a particular cause for concern.
The closure was supported by the Metropolitan Police amid concerns that some motorists were overtaking in the tunnel.
David Brown, from TfL said: "The increasing number of 'near misses' in this enclosed environment poses a significant safety risk and endangers lives.
"This decision has been taken jointly with the Metropolitan Police and is aimed at delivering the highest possible safety standards to London's motorists."
The online petition has so far attracted 100 signatures.
Opposition members of the London Assembly plan to raise the issue with the Mayor of London Ken Livingstone at the next Mayor's Question Time.