Students in Exeter have raised safety concerns about plans to turn off street lights in the city at night.
Devon County Council looks set to approve plans to dim or switch off city lights between 00:30 and 05:30.
It said the scheme, which would cost £1.7m to implement, would then save the authority about £280,000 and 1,600 tonnes of carbon emissions annually.
But University of Exeter Students' Guild said: "The money being saved is at extreme detriment to safety."
Most of the affected lights would be in residential areas with main routes and the city centre remaining lit.
Emma Payne, from the guild, said: "The way students move across the city late at night fit directly between the proposed hours.
"It only takes one person to walk down one street and for it to be dark and for something to happen. I think that is enough to keep a light on."
The Conservative-led authority said it would hold consultations with the police, city council and communities.
David Whitton, from the council, said: "We'll certainly talk to students and we'll develop a network of walking-home routes to accommodate their needs.
"With this new system we can have a different mix so we can look at the particular needs of areas and adjust what we do to suit those particular circumstances.
"Safety is very important and that's why we'll develop a balanced package of measures - the city centre, areas of high night-time activity and the main routes through the city will remain lit."
Mr Whitton said a web-based system would also be used to monitor footfall in areas enabling the 12,000 lights to be changed accordingly.
If approved by the council, the scheme, which is already used in Exmouth, Newton Abbot and Bideford, will be installed in the autumn.
The county council currently has more than 72,000 street lights which cost the authority £3.4m in electricity last year and produced nearly 20,000 tonnes of carbon dioxide.