The party is urging the Scottish Government to introduce a cap on fares to prevent people seeking alternative transport.
The Scottish Government said its concessionary bus travel schemes are the most generous in the UK, with under-22s, over-60s and people with disabilities eligible for free travel.
Passenger bus journeys in Scotland fell by 65 per cent in 2020/21 to 127 million, compared with 363m the previous year, according to Transport Scotland data. In 2007/08, 487m passenger journeys were recorded.
Covid-19 pandemic restrictions are likely to have contributed to the decline.
Statistics also showed fares in Scotland have increased by 6 per cent in real terms over the past five years, compared with a UK increase of 3 per cent.
Mr Bibby said: "The bus services people need every day to get to their work and move around their communities are on the brink of collapse. As a result, more and more people are being forced into cars by unreliable and overpriced services.
"In order to get people back on the buses, we should follow the lead Labour mayors have set in England to cap fares and make public transport affordable once again.
"In Edinburgh, council-owned Lothian Buses' single fares are just £1.80, but elsewhere in Scotland passengers are paying rip-off fares to private bus companies, such as £2.65 for a two-mile journey in Greater Glasgow.”
A Transport Scotland spokeswoman said: "We invest £300m annually to deliver free bus travel for all children and young people under 22, as well as for eligible disabled people and everyone aged 60 and over.
"This means Scotland has the most generous concessionary fare scheme in the UK, with more than 2.3 million people eligible for free bus travel, encouraging more people to choose to take the bus and helping us meet our net-zero targets by encouraging a shift away from cars.”