The number of people using buses has fallen to its lowest level in a decade, according to the latest figures.
Official Government figures say there were 70 million fewer journeys in England in the year ending last March, a decrease of 1.5% over the previous year.
Council leaders say the decline is mainly because of local authorities being forced to reduce funding for services.
The Local Government Association (LGA) warns that the continued decline in bus passenger journeys could mean increased congestion and poorer air quality as well as leaving some people without transport.
It says bus services and routes will remain under threat unless councils are given the powers and funding to protect them.
Cllr Martin Tett, the LGA’s transport spokesman, said: 'It is hugely concerning to see such a steady decrease in bus journeys.
'Buses provide a vital service for our communities and a lifeline for our most vulnerable residents to go shopping, pick up medication, attend doctor appointments or socialise with friends.
'Councils know how important buses are for their residents and local economies and are desperate to protect them.'