Measures backed by counter-terrorism police could see road access limited in a historic city centre to prevent vehicles being used as weapons.
Proposals for the centre of Bath also include removing parking and introducing moving bollards.
Some 200 people have responded to a public consultation, with one residents' association saying vulnerable people could be "trapped".
The council and police say the measures are proportionate to the threat.
Concrete barriers in Bath are already in place but could be replaced with static and moving bollards intended to fit with its Georgian character.
Insp Martin Rowland, from counter terrorism police south west, said: "We know there is a national threat to the United Kingdom from terrorism and we know from past attacks that crowded places have been targeted.
'Safe, secure, protected'
"We always balance the message around terrorism which is for people to be alert but not alarmed.
"This is Bath, not London, but the threat is still there and it is still real."
He said security advisors from his team have been working with Bath and North East Somerset Council on ways to keep the city centre "safe, secure and protected".
A public consultation has now been extended until 31 January to give residents longer to comment on the proposals, which would see all parking - including for blue badge holders - removed from a secure zone.
The Abbey Residents' Association (TARA) said disabled residents face being "trapped".
Chairman Ian Perkins added: "The main issue here is that no-body seems to have thought about people living in the city centre.
"There was extensive consultation with all the businesses and much of the concern is still about businesses.
"We want to highlight the fact that there are people living here, quite a few who are vulnerable, so that there is a proper dialogue about it...and the very real issues that will arise for residents out of this."
Pedestrians, cyclists and emergency vehicles will have access at all times but there will be no access for residents' vehicles, food or parcel deliveries to homes, car parking or taxis.
To maintain safety through the night the council said it will be necessary to introduce new restrictions from 18:00 to 10:00 GMT.
Access controls into Bath city centre are already in place from 10:00 to 18:00 GMT as part of social distancing measures.
Only authorised vehicles such as those from the emergency services, construction vehicles and bank cash lorries are allowed.
Councillor Joanna Wright, cabinet member for transport services, said: "We appreciate how important vehicle access within the city is for our businesses, residents and particularly for people with restricted mobility.
"We have recently appointed a specialist to work with local accessibility groups and other key local stakeholders to look at issues and recommend mitigation measures before the plans are finalised."