Plans to scrap 145 traffic lights in a bid to ease congestion have been criticised due to safety concerns.
Transport for London (TfL) is considering the move after it reviewed the timings at 1,003 signals and found them causing unnecessary delays.
It has also made changes to the timings of other traffic lights, which TfL said reduced delays by 6%.
But the London Labour group said changes may make crossing roads more dangerous for vulnerable pedestrians.
TfL said it would consult about whether the 145 traffic lights should be removed or replaced with alternatives.
Kulveer Ranger, the Mayor of London's transport adviser, said: "There are few things more annoying than sitting at a traffic light on red for no apparent reason and we've now identified 145 sites where we think the signals may no longer be doing a useful job.
"By getting rid of them, we hope we can smooth traffic flow across London and deliver real improvements for all road users."
Labour Assembly member Val Shawcross criticised the plans.
"Pelican crossings are there for the safety and convenience of people on foot but they make up half of the lights proposed for removal," she said.
"If anything we need more safe places to cross busy roads, not less.
"Pensioners, those with disabilities and parents of young children might not shout as loud as car drivers but they're ones who stand to lose out under these plans."